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Time Variation of Cosmic Ray Meson Intensity

FOR THE Ph. D. DEGREE IN PHYSICS OF THE

ALIGARH MUSLIM UNIVERSITY A L I O A R H

SUBMITTED BY R. S. YADAV, M. Sc. (Allahabad)

1965

T H 1 3 I S

Oa

»«TIM1 V.4RlAfI01 OF C03MIG RAY MESON INfESRSIlT"

f o r t h e Ph.D. Degree i n P h y s i c s

of t h e

A l iga rh Muslim U n i v e r s i t y

A l i g a r h .

i I i

S a b a i t t e d by j

E . S . lADAV, M.Sc. (Al lahabad)

1965.

@m

CERTIFIED TEkT THE WORK PRESSI^Si) IN

THIS THJSLlu IS THE ORIGINAL' WOBK CARRIED OUT

B1 ME,

(RAJilNDEA blNQH YADAT) LECTtJESR

DEPARTMENT OP PICTSiC 5 A.M.U. ALIGARH.

Ill

AGKHOLEPgEMEHT

%lille s a l ^ i t t i j a g t h i s t h e s i s the au thor

wishes t o e x p r e s s h i s i n d e h t e d n e a s and g r a t i t u d e

to P r o f e s s o r fiais Ahmed, f o r h i s keen i n t e r e s t

and guidance i n t h e work, f h e au thor i s t h a n k f u l

to Br, P . S . G i l l , D i r e c t o r Gulmarg fie search Obse r -

v a t o r y , f o r p r o v i d i n g t h e f a c i l i t y t o work i n -ttie

O b s e r v a t o r y .

f h e au thor i s a l so t h a n k f u l to h i s c o l l e a g u e s

Dr. R.H.Mathur, Messrs Lekhv i r Sad, Gh. S a s t r y

f o r t h e i r h e l p i n c o l l e c t i n g d a t a a t Gulmarg and

a l s o t o Mr. A j i t S i n ^ , t h e g l a s s - b l o w e r , and Mr.

m^iaa ta l l&h t h e Dept. of p h y s i c s , A.M.U. A l i g a r h ,

f o r h i s h e l p i n c o n s t r u c t i n g t h e G-M c o u n t e r s .

f h e a u t h o r wishes t o thank p r o f . B.C, l o s e , N a t i o n a l

f lesearch Sbunc i l of Canada, f o r s u p p l y i n g d a t a f o r

Ot tawa, C h u r c h i l l , Sulphur Mountain and B e s o l u t e . The

a u t h o r i s g r a t e f u l to P r o f . B a r t e l s f o r supp ly ing

t h e magne t ic d a t a .

Hhe au thor a c k ^ w l e d g e s with thanks the f i n a n c i a l

s i p p o r t i n t h e form of a s c h o l a r a h i p g iven by the M i n i s t r y of S c i e n t i f i c Research and C u l t u r a l A f f a i r s ,

Govt, of I n d i a , i ^ i c h made i t p o s s i b l e f o r him t o

c a r r y o u t t h i s work. Rhwdh^ (B.S.^IADAV.)

JV

COHTiafTS

GHftl^SR I

1 . IRTRODTKTION 1

1 . 1 Dai ly V a r i a t i o n 2

1 . 2 So la r f l a r e e f f e c t on cosmic r ay i n t e n s i t y . . 6

1 . 3 Magnetic storms a s s o c i a t e d viith s o l a r f l a r e s . 8

1 . 4 Schene of t h e t h e s i s . . , . 9

1 . 5 Important r e s u l t s 11

CHAPTER I I

2 . SXPBRIMiSNTAL ARRAKGEME13T 16

2 . 1 G.M. Counters 16

2 .2 C o n s t m s t i o n of t h e t e l e s c o p e . . . . . . . . . . . . . 17

2 . 3 Arrangement f o r narrow ang le t e l e s c o p e s . . . 19

2 . 4 E l e c t r o n i c c i r c u i t s 19

2 . 5 Photographic arrangement 21

CHAPTER I I I

3 . DIURNAL VA-RIAIIGK OF COa^IC-RAY MESOH INTENSITy.23

3 . 0 1 C o r r e c t i o n f o r me teo ro log i ca l f a c t o r s . . . . . 25

3 .02 Harmonic a n a l y s i s 26

3 . 0 3 Study ^rlth c u b i c a l t e l e s c o p e a t Gulmarg . • 2 6

3 . 0 4 Study w i th t e l e s c o p e s of d i f f e r e n t a p e r t u r e s a t <lulimrg 28

3 .05 Day t o day changes i n the d i u r n a l v a r i a t i o n of cosmic- ray meson i n t e n s i t y . . 31

3 . 0 6 Dependence, of t h e d i u r n a l ampl i tude and phase on magnetic c h a r a c t e r f i g u r e C p . . . . . 35

V

3 . 0 7 1&© i<ro3?M«4?ide c o n g e s I n cosmic-^my mason i t t t e i i s i t y aiid t h s l v c o i r e l a t i o n -a l th s o l a r and g e o m g n e t i e a e t i v i t y « « , 3 9

3 . 0 8 a a p l i t u d o tto© plmss of a i u m a l

3*09 S3Q©r^ cteoeMQnee of th© d i t t i m l m ^ i a t l o n • 46

3 . 1 0 Sf>sil-41iimal i r s a l a t l o a 47

3 . 1 1 fhB i ^ l a t i o o s h i p t m ^ m s e s i - a i u f i m l • T a r ^ t i o a geomsgfiatie d i s t u r b a n c e s 51

3»12 Month t o mmtii cteaages I n ttes ampl i tude ai:ia i ^ s e of til© s ^ s i - d i i i r n a l aci^mxBat and t h e i r r e l a t i e j i ^ t h Cp v a l m s and

3«13 OrigSji of s emi^d iu raa l v a r i a t i o n 56

3*14 Biscmssimi 58

3 , 1 5 ^ p l a m t i o a of d i a n s a l ^ a n a t i o a s 61

CMmm 17

4» MTifuBB km mmmm:E O F m DIHRSAI* A® 0P COafSJ-aAT IHfBNSIfJT m

4*1 l a t i t a d o depoisdence o f t h e ampl i tado of t h e di t i iaml and s o s t - d l u i r a a l i r a r i a t iGa 7 3

La t i t t i d s dep^tidenea o f t h e p h a ^ of t h e d i i m j a l and s e s d - d i u r i m l -mr ia t icaa 7 6

4 * 3 A l t i t u d e depeMence of t h e phase 79

4*4 Bisc t i s s ion 82

C H i p m t

B* m m t OP fHS cMniit ? A B i m o H OF COSMIC-KAI i m m s i T t OH MAsimcAiKr ©XOTRBSD AHD q m m DAYS. ^ OIFFUaffl M f l f O I B S IH BOfH fHE H M I ^ E S ^ S 87

S«1 B i a i m l i r a r i a t i m m m g i a e t i c a l l y d i s t u r h e d aisd g t t i e t days 88

S . 2 f h e i^ isss of t h e d i rnmal "Variat ion on d i s t e i r l ) ^ sad < j i ie t d a ^ 95

Vi

6 , 3 Se f f l i - d iu iml coiÊKHaît on and i fo t e t days «•»«»••

S»4 Al t i t ua© aspeM^ne© of plias© on d i s t u r l ^ a and q u i e t days 97

s t u d y of tbs jsatm-e of d a i l y i m r i a t i o i i of cosmic r ay i n t e n s i t y a t d l f f e i ^ n t l a t i t t s d e a I n fcotti t h e h e a i s p h e r e s * . • • » • « . « * » 9 8

S . 6 B l se t i s s ion and i a t e a ^ r e t a t l o n of

ett^PfBB ¥ I

6 . t m t m m m c E m mMM. FL&sss <® f m isarEHsOT OF mm eoMPOHSRi of c o m i c muxmion,^ l o e

• -i CosBSic-say I m t m m a t Ouljaarg = 110

I n f l n s n c c of s m l l s o l a r f l a r e s on t h e laeson I n t e s i s i t y recorded a t h i ^ ^ r geotaagmtic l a t i t t i d e s 113

GHAPfSE

B W m OP f l ® CHAMCfSR OF COailC RA£ INTEHSITY VARIA130H BURIHG SaMB AB0 MAGNETIC Dl^RMf?CES» 120

7 . 1 Method of a n a l y s i s 122

7 . 2 A s s o c i a t i o n between th© d a i l y mean meson I n t e n s i t y and solas* f l a r e s fo l lowed and n o t folloyred l>y laagoet lc-s tojans 122

7«3 V a r i a t i o n of c o a a l e r a y mason i n t e n s i t y w i t h s o l a r f l a r & s . ( fo l lowed a a g n e t i c - s t o r m s ) a t d i f f e r e n t M t l t a d e s .124

7*4 4 s s o c l a t i c m m r i a t i o n s o f meson iGrtânsity ana t h e i m p o r t a n i s of t3ie s o l a r f l a r e s

7*S H e l a t i o n s h i p betwesn tha v a r i a t i o n s of meson I n t e n s i t y and t h e snn-apo t a e t i " ^ t y 130

7 . 6 R e l a t i o n s h i p between s s a l l s o l a r f l a r e s and gecHoagnetie d l s t t i rbanees 132

Vll

Tim d o l a y Irstwaen t h e oecuweiiQe of a s o l a r f l a r e and tii© s t a r t of tha a s s o c i a t e d

7mB D i s c u s s i o n ^ d in te?s ) i?a ta t ioa of e x p e r t a e n t a l r e s i i l t s 134

APPSmX I

APPiaiDlX I I 150

APPENDIX I I I . 1 5 2

1

c h a p t e r — I .

A good dea l of work 021 t ime v a r i a t i o n

of c o a a i c - r a j i a t e n a i t y , u s i n g i o n i s a t i o n diambers

and coun te r t e l e s c o p e s , h a s oeen r e p o r t e d i n the

l i t e r a t u r e ^ . I n r e c e n t y e a r s , n e u t r o n s jojai tors and

s c i n t i l l a t i o n c o u n t e r s have a lao been employed i n

the stu<^y of t i m e - i r a r i a t i o n of cosmio - r aya . I t

h a s cose t o ^ r e a l i s e d t h a t fromjfche study of t i m e -

v a r i a t i o n of cosjaaic-rgys mudi c ^ be l e a r n t d i r e c t l y

about t h e mechaniam o f ^ t h e i r p r o d u c t i o n , "to-eir

o r i g i n and p r o p a g a t i o n to t h e ea i ' t h , and a lso a\J0ut

the v a r i o u a i n f l u e n c e s on them a r i s i n g from the

e l e c t r o m a g n e t i c c o n d i t i o n s of i n t e r p l a n e t a r y space

and of the Sun. I n view of t h i a impor t ance , the

I n t e r n a t i o n a l Greophysical Year i n c l u d e d

i n i t s programme t h e study of t i m e - v a r i a t i o n of the

h a r d component of cossa ic- rays oy means of s t a n d a r d i z e d

cubical-me son t e l e s c o p e s . Neutron m o n i t o r s and a l so

i o n i z a t i o n chaffi-bers were o p e r a t e d a t v a r i o u s s t a t i o n s

sp read th roughou t the •Korld dur ing t h e I . Q . Y . progrsBaaa©,

1 . H . E l l i o t , p r o g r e s s i n Cosmic-ray P h y s i c s , ? o l . I , 4 5 5 , ( 1 9 5 2 ) .

I n t h i s t h e s i s d a t a c o l l e c t e d a t Gulsa rg

have been u t i l i z e d , ba t -Hae r e s u l t s o b t a i n e d a t o t h e r

s t a t i o n s have a l so beezi a n a l y s e d ^^iaere nf ioessary ,

&xilmarg d a t a was c o l l e c t e d b j a c o a b i n a t i o a of f o u r

t e l e s c o p e s » a c u b i c a l t e l e s c o p e , and w i t h i n i t

1 4 , 5 ^ , 7® and 4® t e l e s c o p e s .

33AILY YARlAflOH

Most of the c o s m i c - r ^ i n t e n s i t y Y a r i a t i o n s

obse rved a t s e a - l e v e l a re due t o a tn jospher ic e f f e c t s .

Ihen t h e s e e f f e c t s have been el iminatfed a omall d a i l y

v a r i a t i o n r ema ins . Tq e l i m i n a t e the e f f e c t of

a tmospher ic px^easure caad t e m p e r a t u r e on cosiaic-r^y 2

i n t e n s i t y , IXiperier i n v e s t i g a t e d a r e l a t i o n of t h e

t y p e .

AI « p> Ap + V A t

^ e r e - a j , ^ p , and ^ t r e p r e s e n t v a r i a t i o n s

i n cosifiic-ray i n t e n s i t y , ba rome te r ! c p r e s s u r e and

a tmospher ic t e m p e r a t u r e . Suda a t t e m p t s d id n o t , however,

always r e s u l t i n e o n a s t e n t v a l u e s f o r t h e p r e s s u r e

and t empera tu re c o e f f i c i e n t |2>snd V mainly because

the cho ice of the v a r i a b l e A t «as r a t h e r ambiguous

2 . A. B u p e r i e r , Hature 158, 196 ( 1 9 4 6 ) .

as i t was d i f f i c u l t to as^r wtiich p a r t of t h e atmosphere

should fee cons ide red f o r i t s t e m p e r a t u r e v a r i a t i o n s .

R e c e n t l y , IhrmsxiP and o t h e r s have sugges ted

t h a t i ( i ) f o r t he p r e s s u r e c o e f f i c i e n t p , one i ^ou ld

u s e a s t a n d a r d v a l u e which can he t h e o r e t i c a l l y

e s t i m a t e d ; ( i i ) f o r c a l c u l a t i n g t h e t e m p e r a t u r e

e l l e c t s , one slaould e-valuat^ i l^s e o n t r i b ' a t l o n t r o a

d i f f e r e n t l a y e r s of t he atmosphere s e p a r a t e l y .

A p r e c i s e knoT/ledge of t h e a tmospher ic c o n d i -

t i o n s to.ring the pe r iod of o b s e r v a t i o n i s r e q u i r e d

t o c a l c u l a t e t h e e f f e c t mentioned i n ( i i ) . 31his i s

d i f f i c u l t to o b t a i n . I n t h e case o f smal l a p e r t u r e

t e l e s c o p e s the c o a n i c - r a y v a r i a t i o n s a r e of t h e o r d e r

of l i b - c^t hence d a t a i s a lmost u n a f f e c t e d by

t e m p e r a t u r e . I n the c a s e of n e u t r o n moni to r d a t a ,

t he t empera tu re e f f e c t i s i n B i g n i f i c a n t said b a r o m e t e r i c

p r e s a i r e e f f e c t i s ve ry we l l known. Shus both t h e s e

t y p e s of ins t r t i i aen t s , namely na r row-ang le t e l e s c o p e s

and n e u t r o n m o n i t o r s can be e f f e c t i v e l y employed i n

the s tudy of t ime v a r i a t i o n .

Pur the rmore , r e a l i z a - t i o n h a s sroT.7n i n r e c e n t

3 . L . I . Dorman, Gosmic-ray v a r i a t i o n s (1957) ; „

y e a r s t h a t tho s o l a r a n i s o t r o p y of cos tn io-rays i s

of a h i ^ l y Yariatele c toarac ie r^*^ . S i i s char a s t e r

of t a e s o l a r a n i s o t r o p y has been s t u d i e d Xn t he

p a s t by oae or two workers by measur ing tiia s o l a r

d a i l y v a r i a t i o n du r ing the p e r i o d of sd-EiaHMi a o l a r

a c t i v i t y on ly a t low l a t i t u d e s , f h e s o l a r and

t e r r e s t r i a l r e l a t i o n s a i g s of ti ie d i anges of a n i s o t r o p y

have a l s o Deen s t u d i e d p r e v i o u s l y and t i i e o r i e s have

been advaaoed to e z p l a i n the c r e a t i o n of Hie a n i s o t r o p y

by a modu la t i on mechanism* A c o n f i r m a t i o n of t h e s e

expe r imen ta l o b s e r v a t i o n s and proposed models i s of

c r u c i a l s i g n i f i c a n c e to t h e t h e o r i e s of t he o r l ^ n

of c o a a i c - r a y s and of the e l e c t r o m a g n e t i c c o n d i t i o n s

of i n t e r p l a n e t a i ^ space . Hence i t was dec ided to c a r i y

out an exper imenta l s tudy a t a middle l a t i t u d e and

h i ^ a l t i t u d e s t a t i o n dur ing t h e y e a r of mazismm s o l a r

a c t i v i t y , f h e meaairements were c a r r i e d o u t a t

Gulmarg ( X « 24.7®Br» 9000 f t . ) by means of t h r e e

na r row-ang le t e l e s c o p e s hav ing s e m i - a n ^ e s of

and 14^5°. I n our view t h i s s tudy would compliment

the e a r l i e r low l a t i t u d e s t u d i e s dur ing y e a r s of

ainiffium s o l a r a c t i v i t y » ^hus oar study may h e l p i n

e s t a b l i s h i n g a more c o n s i s t e n t t heo ry of t h e

4 . Y-Sarabhai and H.W. Keru rka r , Annuiil S e v . S u c l e a r , S c i . , 6 , 1 , (1958) .

5

e l e c t r o m a g n e t i c c o n d i t i o n s i n ttie i n t e r p l a n e t a r y

space and t h e o r i g i n of cosmic-raya»

Simpson and o t h e r s have shown tha t - . t he diurned

v a r i a t i o n of the n e u t r o n component i s n e a r l y t h r e e

t i m e s t h a t of t h e h a r d component. O b s e r v a t i o n s on the

h a r d (^mponent of t he 0 3 s m i c - r a d i a t i o n a t s e a - l e v e l

p rov ide i n f o r m a t i o n on the energy p a r t of the

primary cosmio-ray beam. I n f o r m a t i o n on t h e low

energy p a r t of t h e &eam may be o b t a i n e d a t s e a - l e v e l

by s tudy ing t h e i n t e n s i t y of the n e u t r o n component,

2hus , f o r \ i n d e r s t a n d i ^ t h e energy spectrum of t h e

pr imary a n i s o t r o p y , a very i m p o r t a n t t o o l i s the s tudy

of t h e SEpl i tude and phase of t h e d a i l y v a r i a t i o n of

cosmic-ray meson and n e u t r o n i n t e n s i t y a t d i f f e r e n t

l a t i t u d e s .

5 E a r l i e r r e s u l t s of Thompson (1958) * Lange

and Forbush (194a )^ , ThambyahpillaL and E l l i o t (1953)"^ 8

and F i r r o r e t* a l . (1954) have shown t h a t t h e

ampl i tude of the dixirnal v a r i a t i o n of t h e mason and

3. J.L.Thompaoii, Phya. Rev . , 93 (133S) . 6 . I ,Lange and S .B.Porbush, Carnegie I n s t i t u t e of

Washington, P u b l i c a t i o n 175 (194-8). 7 . f h a m b y a p i l l a i and E . E l l i o t , ITature, 171^918(1953)* 8 . J . A . P i r r o r , l . H . fonge r and J .A.Simpcon, p h y s . R e v , ,

£ 4 , 1051 ( 1 9 5 4 ) .

6

u e u t r o n eompO£.€nt <aoQs not dopand on gcorsagnetic

l a t i t i x a e s . But liie l a t i t u d e dependence of t h e

phase of t h e s e oomponents was not s t u d i e d l a Itoe

p a s t by t h e s e or o t h e r i n v e s t i g a t o r s *

'fhe e a r l i e r r e s u l t s were a l s o , not v e r j

s y s t e m a t i c between the r e g i o n from the e q u a t o r to

t h e po le i t i both t h e hemisphe re s . Cont inuous measure -

ments of meson and n e u t r o n i n t e n s i t y of coera ic- rays

d u r i n g t h e i n t e r n a t i o n a l Geophysical Year {1957-58)

sore i m p o r t a n t i n mgfeing a s y s t e m a t i c s tudy of t h i s

prohlem* Hence u s i n g Uie d a t a of meson smd n e u t r o n

i n t e n s i t y c o l l e c t e d dur ing the I . G . Y . a t l a t i t u d e s

from 75'^S to 83®R, se s t u d i e d ^ f s t e m a t i c a l l y the

l a t i t u d e dependence of ampl i tuds and phase of the

d i u r n a l comporiant i n both the h e m i s p h e r e s , Using

the same d a t a we a l so examined the a l t i t u d e dependence

of tiie ampl i tude and phase* By t h i s s tudy an i m p o r t a n t

r e s u l t fSaich we oboerved f o r the f i r s t time i s t h a t

t h e phase of the d i u r n a l v a r i a t i o n d e c r e a s e s a s t h e

l a t i t u d e i n c r e a s e s i n the n o r t h e r n hemisphere . But

a ich a n a t u r e of phase was no t observed i n the sou-

t h e r n hemisphere .

1 . 2 SOLAK FLAKE BPfECf OM COSMIC-BAY IMTEMSITI

I n t h e l a s t few y e a r s a t t e n t i o n of s e v e r a l

7

i n v e s t i g a t o r s h a s been a t t r a c t e d by t h e cosmic - r ay

i n c r e a s e s a s s o c i a t e d vvlth. s o l a r f l & r e s i raostj^y w i th

l a r g e s o l a r f l a r e s . Cosmic- ray v a r i a t i o n s of t h i s

c l a s s a r e e x t r e m e l y i n t e r e s t i n g s i n c e t h e y y i e l d

v j ^ u a b l e i n f o r m a t i o n abou t how low energy c o s m i c - r a y s a t

a r e g e n e r a t e d t h e s u a , and abou t p r o c e s s e s i n the

s o l a r a tmosphere , t h e i scopaga t ion of a c c e l e r a t e d

p a r t i c l e s t h r o u ^ the c o r o n a and t h e supe r co rona

of t h e aan, and about p r o p a g a t i o n i n i n t e r p l a n e t a r y

s p a c e .

Uar ing t h e p a s t s e v e n t e e n y e a r s t h e r e have

been f i v e l a r g e cosmic - ray i n c r e a s e s a s s o c i a t e d

wi th t h e o c c u r r e n c e of l a r g e s o l a r f l a r e s ^ * ^ \saaich

have been o b s e r v e d d i r e c t l y . Ihe laoat i n t e n s e of

t h e s e , on 23rd f e b . 1956, r e s u l t e d i n 50 f o l d

i j a c r ea se of t h e i n t e n s i t y of t h e p r i a a r y r a d i a t i o n

i n iiie energy r e g i o n 1 - 1 0 Bevj and a 5 f o l d i n c r e a s e

i n t h e re^^ion of 10-1000 Bev. I t was e l s o p o s s i b l e

to ^ o w t h a t the p a x ' t i c l s s csne f rom the s a n , t h a t

t h e i r mean energy was about 4 Bevj and t h a t they were

p r edominan t ly p r o t o n s .

I t h a s been obse rved t h a t s m a l l e r i n c r e a s e s

a r e o f t e n a s s o c i a t e d -with the s m a l l e r s o l a r f l a r e s ,

8

anSd the ave rage i m e r e a s e i s of o r d e r of a

few p e r c e n t . S ince on ly a few s t u d i e s Have been

made i n t h i s d i r e c t i o n , i n o r d e r to e x t e n d such

i n f o r m a t i o n we a n a l y s e d d a t a f rom t h r e e h i ^ l a t i t u d e

s t a t i o n s . We o b s e r v e d an i n c r e a s e i n meson i i i t e n ^ t y

on 19 th J u n e , 195S, a t Sulmarg a s s o c i a t e d Ydth a

smal l s o l a r f l a r e o f i m p o r t a n c e 2 , r e p o r t e d by

KodgdkG»al S o l a r O b s e r v a t o r y ( I n d i a ) . We a l s o exao ined

t h e average e f f e c t of s m a l l s o l a r f l a r e s of impor t ance

1 and 2 on cos ia ic - ray i n t e n s i t y by p e r f o r m i n g a

s t a t i s t i c a l s t u d y -

1 . 5 MAgMiaiC SfOBMS ASSOCIATED VITH SOLAR gLARllS

f h e s t u c ^ of c o a n i c - r e y d e c r e a s e s a s s o c i a t e d

v d t h m a g n e t i c s torms i s i m p o r t a n t fro/a t h e p o i n t ot

view of u n d e r s t a n d i n g tho g e n e r a l p i c t u r e o f c o a a i c -

r a y m o t o l a t i o n i n t h e s o l a r sy s t em. S h i s study i s

a l eo u s e f u l , because i t p r o v i d e s Viiluable i n f o r m a t i o n

to u n d e r s t a n d t h e e l e c t r o m a g n e t i c c o n d i t i o n s of

t h e corpUGCttlar streams e j e c t e d from tne sun and

t h e i r i n t e r a c t i o n Yiith t h e i n t e r p i aMetai-y mediiin and

the e a r c h .

f l a i l i e r s t u d i e s de^^oted to t h e e f f e c t s 9 . L . I . Dorm an, p r o g r e s s i n e l e m e n t a r y p a r t i c l e ana

cosmic - r ay p h y s i c s , Vol. ? i l , ( 1 9 6 3 ) . 1 0 . p r o c e e d i n g s of the Moscow Cosraic-rOT Conference

V o l . 4 , ( 1 9 6 ^ ) .

9

of magne t i c s to rms on cosmic - ray i n t e n s i t y were

main ly based on l a r g e s to rms , hence we thougbit i t

wor thwhi le t o s t u d y t h e c h a r a c t e r of t h e p r o f i l e

of t h e cosmic - r ay d e c r e a s e s wi th magne t ic s to rms

which f o l l o w s o l a r f l a r e s * Por t h i s purpose

we s e l e c t e d t h r e e i i i ^ l a t i t u d e s t a t a t i o n s and a n a l y s e d

t h e d a t a c o l l e c t e d t h e r e di i r ing t h e I . G . Y . p e r i o d .

T h i s b e i n g a l s o t h e p e r i o d when t h e f r e q u e n c y of

o c c u r r e n c e of such magne t ic s to rms was s u f f i c i e i s t l y

l a r g e . We b e l i e v e , our s tudy w i l l be h e l p f u l i n

p r o v i d i n g i n f o r m a t i o n about t h e way t h e e a r t h e n t e r s t h e

s t r eam, t h e v e l o c i t y of t h e s t ream and the d i s t r i b u t i o n

of t h e f i e l d i n i t . I t w i l l a l s o p rov ide a check t o

examine t h e e x i s t i n g models and t h e o r i e s ;(?Siich were

main ly proposed t o e x p l a i n t h e f e a t u r e s of l a r g e cosmic-

r a y d e c r e a s e s d u r i n g t h e l a r g e magnet ic s torms) con-

ce rn i i j g cosmic- ray d e c r e a s e s d u r i n g magne t ic s to rms

a s s o c i a t e d wi th smal l s o l a r f l a r e s .

1 . 4 SCHEME Of THESIS

She work which we d i d on d i f f e r e n t a s p e c t s

of t i m e - v a r i a t i o n of cosmic- ray i n t e n s i t y , i s p r e s e n t e d

i n t h i s t h e s i s i n t h e f o l l o w i n g o r d e r

10

I n t h e second c h a p t e r t he c o n s t r u c t i o n and

w j r k i n g of t h e meson c u b i c a l t e l e s c o p e a long witii

t h e t h r e e nar row-angle t e l e s c o p e s i s g iven i n d e t a i l ,

f h e e l e c t r o n i c c i r c u i t s which ^e des igned f o r our

purpose a re a l l b a t t e r y o p e r a t e d and baaed on

m i n i a t u r e tubes« f h e s e a re a l s o d i s c u s s e d i n t h i s

c h a p t e r .

I n t h e t h i r d c h a p t e r t h e d i u r n a l v a r i a t i o n of

c o a a i e - r a y meson i n t e n s i t y and i t s r e l a t i o n to t h e

magnet ic c h a r a c t e r f i g u r e Cp and sunspo t numbers i s

s t u d i e d . £he v a r i a b l e c h a r a c t e r of t h e s o l a r a n i s o t r o p y

i s a l s o examined by s tudy ing t h e day to day changes i n

t h e d i u r n a l v a r i a t i o n of cosmic - ray i n t e n s i t y r e c o r d e d

by na r row-ang le t e l e s c o p e s .

I n the f o u r t h c h a p t e r t h e l a t i t u d e and a l t i t u d e

dependence of the ampl i tude and phase of t h e d i u r n a l

and the s e m i - d i u r n a l v a r i a t i o n of cosmic- ray meson and

n e u t r o n i n t e n s i t y i s s t u d i e d .

The f i f t h chap t e r d e a l s wi th a s y s t e m a t i c s tudy

of t h e n a t u r e of t h e d i u r n a l and" s e m i - d i u r n a l v a r i a t i o n

of meson a s we l l a s n e u t r o n i n t e n s i t y on m a g n e t i c a l l y

q t i ie t and d i s t u r b e d days a t d i f f e r e n t l a t i t u d e s i n both

t h e hemisphe res .

11

She s i x t h c h a p t e r d i s c u s s e s t h e e f f e c t of

small s o l a r f l a r e s on cosmio-ray meson i n t e n s i t y .

"the seven th c h a p t e r t h e c h a r a c t e r of t h e

cosmic r a y i n t e n s i t y v a r i a t i o n s d u r i n g the magnet ic

d i s t u r b a n c e s a s s o c i a t e d with smal l s o l a r f l a r e s i s

s t u d i e d .

1 . 5 IMPORgAHT RESPLSS :

Some of t h e i m p o r t a n t and i n t e r e s t i n g r e a i l t s

which we found i n our s tudy d u r i n g the y e a r of

maximtua s o l a r a c t i v i t y a re l i s t e d below i

( i ) f h e ampl i tude of the d i u r n a l and s e m i - d i u r n a l

components of meson as we l l a s n e u t r o n i n t e n s i t y does

not show any s y s t e m a t i c l i n e a r r e l a t i o n s h i p with

l a t i t u d e . But a t p o l a r , s t a t i o n s t h e ampl i tude of t i e

d i t i rna l v a r i a t i o n i s a p p r e c i a b l y sma l l e r t han a t o t h e r

s t a t i o n s .

Another very ^ g n i f i c a n t p o i n t obse rved i s t h a t

f o r t h e meson i n t e n s i t y i n t h e n o r t h e r n hemisphere ,

t h e d i u r n a l and s e m i - d i u r n a l smpl i tude a t f i r s t

increase^sd- th l a t i t u d e , bu t the t r e n d i s r e v e r s e d a t

about a l a t i t u d e of the r e a s o n f o r t h i s s t r a n g e

behaviour h a s y e t t o be found .

12

( i i ) f h e pbase of t h e d i u r n a l v a r i a t i o n of cosmic-

r a y meson and n e u t r o n i n t e n s i t y d e c r e a s e s a s t h e

geomagnetic l a t i t u d e i n c r e a s e s i n the n o r t h e r n

hemisphe re . But such a hehavioi ir of phase with

l a t i t u d e i s not found i n the s o u t h e r n hemisphere .

( i i i ) Th i s l a t i t u d e dependence of phase of t h e

d iuxna l v a r i a t i o n remains u n a f f e c t e d on d i s t u r b e d

and q u i e t days .

( i v ) The phase of the s e m i - d i u r n a l v a r i a t i o n of

coamic- ray meson as we l l a s n e u t r o n i n t e n s i t y does not

bear any s y s t e m a t i c l i n e a r r e l a t i o n wi th geomagnet ic

l a t i t u d e s i n bo th the hemisphe re s . But on m a g n e t i c a l l y

q u i e t days t h e phase of both the meson snd n e u t r o n

i n t e n s i t i e s d e c r e a s e s with l a t i t u d e i n the n o r t h e r n

hemisphere o n l y .

(v) The phases of t h e d i u r n a l and s e m i - d i u r n a l

components of t he d a i l y v a r i a t i o n s occur e a r l i e r a t

h ig j i e r a l t i t u d e s . IThis i s found f o r both t h e meson

and n e u t r o n i n t e n s i t y phase s .

( v i ) The average d a i l y v a r i a t i o n of t h e n e u t r o n

i n t e n s i t y on m a g n e t i c a l l y d i s t u r b e d days a t d i f f e r e n t

l a t i t u d e s i n both the hemispheres , h a s tv?o maxima

13

and two miQima. file i m p o r t a n t po in t wiaicla<4s o b s -

e rved by u s i s t h a t tiie geSieral n a t u r e of t h e d a i l y

v a r i a t i o n of n e u t r o n i n t e n s i t y i n the n o r t h e r n hemis -

phere i s o p p o s i t e to t h a t of t h e d a i l y v a r i a t i o n

i n t h e s o u t h e r n hemisphere .

< v i i ) On q u i e t days t h e average d a i l y v a r i a t i o n s

of meson and n e u t r o n i n t e n s i t y g e n e r a l l y have on ly

one mazima and one minima.

I t i s a l so foiind t h a t t he gene ra l n a t u r e of

the d a i l y v a r i a t i o n of meson and n e u t r o n i n t e n s i t y

i s s i m i l a r a t d i f f e r e n t geomagnetic l a t i t u d e s i n

t h e n o r t h e r n hemisphere , but i t i s not so i n t h e

sou the rn hemispheres .

( v i i i ) On 19th of June 1958 we obse rved an

i n c r e a s e of meson i n t e n s i t y a s s o c i a t e d wi th a s o l a r

f l a r e of impor tance 2. This i n c r e a s e was d e t e c t e d

with t h r e e t e l e s c o p e s l i av ing s emi -ang le s 4®, 14.5®

and 45° ( c u b i c a l ) , and i t was 41.29+5.27^,17.23+3

19.36+0.50?^ r e s p e c t i v e l y .

( i x ) I n t h e case of f l a r e s f o l l o w e d by magnet ic

s to rms , vre found t h a t the average meson i n t e n s i t y

i n c r e a s e s even b e f o r e t h e f l a r e day. The maximum

14

i n c r e a s e i s about 0 .17+0-056^ a t about two days b e f o r e

t h e f l a r e day. A f t e r t he f l a r e , t h e i n t e n s i t y f a l l s

below i t s average v a l u e , and r e a c h e s the minimum

vsO-ue -0 .24+0 .056^ t h r e e days a f t e r t he f l a r e .

But i n t h e case of f l a r e s not fo l l owed by mag-

n e t i c s torms , t h e meson i n t e n s i t y shows a t r e n d which

i s i n phase o p p o s i t i o n to t h e case j u s t d i s c u s s e d .

Average i n t e n s i t y shows a minimum of about - 0 . 8 1 + 0 « 0 4 ^

n e a r l y two days p r i o r t o the f l a r e . I t r e t u r n s to

normal v a l u e , and t hen i n c r e a s e s t o about 4'0.31+0«04-25&

two to t h r e e days a f t e r t h e f l a r e .

(x) Another po in t r e g a r d i n g t h i s dec rease i s t h a t

the ampl i tude of t h e dec rease ( c a l l e d dip) of t h e

meson i n t e n s i t y observed a f t e r t he f l a r e cay ( o n l y

i n case of f l a r e s f o l l o w e d by magne t i c s torms) does

not show any l a t i t u d e dependence. However, t h i s d ip

o c c u r s l a t e r a s t h e geomagnetic l a t i t u d e i n c r e a s e s -

I t i s a l s o obse rved t h a t t h i s d ip becomes more and

more sha l low as t h e po le i s approached. This i n d i c a t e s

t h a t t h e p r o f i l e of the d ip and i t s time of o c c u r r e n c e

a re r i g i d i t y dependent .

( x i ) This c o a a i c - r a y decrease ( d i p ) i s a l so of

world-wide n a t u r e .

( s i i i ) Ihe magnitude of t i i i a dec rease i s

l a r g e r f o r magne t ic s torms a s s o c i a t e d wi-Hi f l a r e s

of impor tance 2 , tliiin f o r t h o s e a s s o c i a t e d witii

f l a r e s of impor tance 1 .

15

CHAggBi . - I I .

EliMilMESgAL ASaASaMEHS

2 . 0 We s h a l l mw d e s c r i b e t h e equipment which

was u sed f o r c o l l e c t i n g t h e c o s a a i c - r ^ meson i n t e n s i t y

d a t a a t Golmarg, p a r t l y d u r i n g t h e IQX programme.

Gulmarg i s a h i l l s t a t i o n a t a h e i g h t of 9000 f t . , and

a geomagnet ic l a t i t u d e of 2 4 . 7 ° S . The Gulmarg Resea rch

O b s e r y a t o r y i s s i t u a t e d on a h i l l c l e a r of a l l s u r r o u n -

d i n g s , and communicat ion w i t h t h e O b s e r v a t o r y i s ve ry

d i f f i c u l t , e s p e c i a l l y d u r i n g t h e w i n t e r months . The

d i e s e l e l e c t r i c supply i s no t f u l l y dependab le when

d a t a h a s t o be c o l l e c t e d w i t h o u t a b r e a k .

I n view of t h i s d i f f i c u l t y , a l l t h e e l e c t r o n i c

c i r c u i t s had t o be d e s i g n e d f o r b a t t e r y o p e r a t i o n and

c o n s e q u e n t l y m i n i a t u r e t u b e s were u s e d . We d e s i g n e d t h e

quisnching, c o i n c i d e n c e , d i s c r i m i n a t o r and t h e s c a l e r

C i r c u i t s .

The c o u n t e r s u sed were a l s o c o n s t r u c t e d

i n t h e l a b o r a t o r y of t h e Depar tment of P h y s i c s , A l i g a r h

Muslim U n i v e r s i t y , i a i g a r h .

Details of a l l t h i s equipment a r e g i v e n below

2 . 1 &-M. GOOBTaES

. S ^ f - q u e n c h i n g S-M c o u n t e r s were u s e d w i t h

17

dimensions shown i n f i g . 1 . Pyrex ^ a s s envelope

had an o u t s i d e d iameter of 1*63 i n c h and a t h i c k n e s s

of 0 . 0 6 i n c h , f h e e f f e c t i v e l e n g t h of t h e copper

ca thode was 23.0 i n c h e s and i t s d iamete r was 1 . 5 i n c h ,

fmngs tun anode of 3 m i l d iameter was u s e d . An

a p p r o p r i a t e a p p a r a t u s f o r e v a c u a t i o n and gas f i l l i n g

was s e t up .

2 . 2 QOgSfEUCflQH Qg THE gSLESGOPE

The meson c u b i c a l t e l e s c o p e # i i c h was cons -

t r u c t e d a t Gulmarg Research O b s e r v a t o r y was s i m i l a r

t o t h e s t a n d a r d meson c u b i c a l t e l e s c o p e recommended if

by t h e ooamic-ray sub-commit tee of t h e i n t e r n a t i o n a l

Union of Pure and Appl ied p h y s i c s to s tudy the t i m e -

v a r i a t i o n of meson i n t e n s i t y i n t h e lower atmosphere

d u r i n g t h e I n t e r n a t i o n a l Geophysica l y e a r 1957-58.

The arrangement of c o u n t e r s w i t h t h e i r

a s s o c i a t e d e l e c t r o n i c u n i t s i s shown i n schemat ic form

i n f i g . 2 . The t e l e s c o p e c o n s i s t e d of f o u r t y f i v e

GrH5$ c o u n t e r s and t h e s e were a r r anged i n t h r e e t r a y s

^diich were e l e c t r o n i c a l l y coupled i n t r i p l e co inc idence

a r rangement . The t r a y s were aarranged one above t h e

o t h e r and t h e top and bottom t r a y s were s e p a r a t e d by

a d i s t a n c e of 25 i n c h e s . The c o u n t e r s were p l a c e d

Copper Cylino<R 5v«tl ToM&'STrvj Seoil off, cxfif' I'ltK'K wilh M -VXUT'

Glass Envelope 23

Glass slmm

Fx l GLA;,S ENVELOPE G-M. COUNTER

^ 3

V t/N/T e ^COWC/Ot/VCi i/MT D iD/SC/l/M/N^TO/^ S --.SCf/l£ft

O/" G./yr. CO(/Afrs/?S M^/r^ t^S/^ /^SJOCtfiTED £L£CT/?0N/C OAf/TS.

18

With t h e i r axes p a r a l l e l t o t h e E-?? p l a n e , t h e

t e l e s c o p e hav ing a semi -ang le 45® i n the E-W p l a n e

a s v?ell a s i n t h e S-S p l a n e .

fwo s l a b s of l e a d , each 5 cm. t h i c k , were

p l a c e d bettf/een t h e co imte r t r a y s i n o r d e r t o c u t o f f

t he / so f t component, and a l low e s s e n t i a l l y t h e jkLmesons

t o be r e c o r d e d .

S h ^ h o l e of the t e l e s c o p e t o g e t h e r ?.'lth t h e

h igh t e n s i o n b a t t e r i e s was enc losed i n a t empe ra tu r e

c o n t r o l l e d c a b i n e t m a i n t a i n e d a t 2 7 ^ 1 ^ 0 . 2he temper -

a t u r e of t h e c a b i n e t was ma in t a ined wi th t h e h e l p of a

mercury the rmo- reguXator .

f h e average coun t ing r a t e of t h e t e l e s c o p e was

about 45fOOO t h r e e f o l d c o i n c i d e n c e s per h o u r , f h e

count was r e c o r d e d a t h o u r l y i n t e r v a l s by pho tog raph ing

t h e t e l e p h o n e c a l l r e c o r d e r . Between t h e r e c o r d e r azui

t h e t r i p l e co inc idence c i r c u i t t h e r e was a s c a l i n g f a c t o r

of 128.

Leav ing a s i d e t h e end c o u n t e r a s an independen t

quenched u n i t t h e r e s t of t h e f o u r t e e n c o u n t e r s were

d iv ided i n t o seven s e t s of two c o u n t e r s each, and each

s e t of two c o u n t e r s was connected to one quenching u n i t .

I n t h i s w ^ e i ^ t quenching u n i t s (Q) were put i n each

t r a y a s shown i n f i g . 2 . f h e p u l s e s from t h e s e quenching

19

u n i t s were connec ted l a p a r a l l e l and f e d t o t i ie

c o i n c i d e n c e u n i t (C) , which i n c o n j u n c t i o n wi th t h e

d i s c r i m i n a t o r (B) s u p p l i e d t r i p l e c o i n c i d e n c e p u l s e s

t o t h e s c a l e r ( 3 ) .

2 . 3 ABEASGMEHg FOfi HASROy«AH&L£ g£L£SOQP£S

f h e c u b i c a l t e l e s c o p e d e s c r i b e d above was

d i v i d e d i n t o t h r e e na r row-ang le t e l e s c o p e s , P i g . 5 ( a ) ,

hav ing s emi - ang l e s 4®, 7° and 14.5^ i n t h e H-S p l a n e

and 45® each i n the E-W p l a n e . I t may be noted t h a t

t h e s e t e l e s c o p e s c o n s i s t e d of one» two and f o u r

c o u n t e r s e a c h .

Three s e p e r a t e co inc idence u n i t s were employed

f o r t h e s e n a r r o w - a n ^ e t e l e s c o p e s and t h e o u t - p u t of

t h e c o i n c i d e n c e d i s c r i m i n a t o r combina t ion of each c i r c u i t

was r e c o r d e d s e p e r a t e l y a f t e r i n t r o d u c i n g a s c a l e of f o u r ,

P ig , 5 ( b ) . !I?he t e l e p h o n e c a l l r e c o r d e r s connected w i th

t h e narrow ang le t e l e s c o p e s were a l s o pu t nea r t h e main

r e c o r d e r f o r be ing piwDtographed every h o u r .

2 . 4 ' ELECfRQHIC ClBCmiES

I h e quenching u n i t s and the c o i n c i d e n c e u n i t s ,

which were wired on t h e s ^ e c h a s s i s were p l a c e d oh

t h e coun t e r t r a y s , whi le t h e s c a l e r s and the power

s u p p l i e s were p u t i n a s e p e r a t e c a b i n e t shown i n

photograph 1 .

cocoDooocooqocp

3r«>.

<y oc/sTAX/VAvtr î^/r C OOMCi OfAY t/ /T D ZWCWf nw*/* J TCtt^fjt €3X- ^ A* •rtrWWA'V -

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1 -

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f h e c o u n t e r s were checked from t h e back

door of t h e t e l e s c o p e c a b i n e t toy t a k i n g t h e c o u n t i n g

r a t e of t h e i n d i v i d u a l c o u n t e r s wi th the h e l p of a

coamerc i a l s c a l e r , and the p u l s e s were checked on an

o s c i l l o s c o p e . I h e t e s t i n g of the c o u n t e r s was done

every morning and n i ^ h t .

I n t ime v a r i a t i o n expe r imen t s where r e l i a b l e

o p e r a t i o n of t h e c o u n t e r s o v e r a l ong p e r i o d of t ime i s

e s s e n t i a l , t h e u s e of quenching u n i t s improves t h e f l a t -

n e s s of t he p l a t e a u and p r o l o n g s t h e l i f e of t h e quenched

c o i m t e r s by s u p p r e s s i o n of m u l t i p l e d i s c h a r g e s , t h e r e -

f o r e , a quenching c i r c u i t , f i g . 4, was u s e d .

I n o r d e r to s i m p l i f y t h e w i r i n g , conse rve

power from t h e b a t t e r i e s and minimize p u l s e a t t e n u a t i o n , n

t h e quenching and c o i c i d e n c e u n i t s were wired on t h e A

same c h a s s i s . SPhe c o i n c i d e n c e c i r c u i t f o r t h e c u b i c a l

t e l e s c o p e and t h e n ^ r o w - a n g l e t e l e s c o p e s a r e almost

thejsame except f o r the g r i d r e s i s t a n c e which i s d i f f e r e n t

i n t h e %m c a s e s , f h e c i r c u i t diagram i s shown i n F i g . 5 .

The s c a l i n g u n i t c o n s i s t s of f i v e c i r c u i t s t ( i ) d i s c r i m i n a t o r , shown i n F i g . 6 , and ( i i ) p u l s e - s h a p e r

( i i i ) s c a l e r ( i v ) a m p l i f i e r and (v) Eecorder d r i v e shown

i n F i g . 7 . f h e c i r c u i t of t he s c a l e r used wi th t h e narrow

t e l e s c o p e s i s shown i n F i g . 8 .

t I J,/ i\ UvxKtHtwt. CiMcmf

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21

f h e p o s i t i v e p u l a e s from t h e c ^ c i d e n c e

c i r c u i t were f e d t o a d i s c r i m i n a t o r Dsiiose ou t p u t was

a square p o s i t i v e p u l s e c o r r e s p o n d i n g t o the conc iden t t\. e v e n t , f h i s p u l s e was g iven a c o r r e c t shape to s u i t

t h e s c a l i n g c i r c u i t vfeich r e q u i r e d 4 - v o l t n e g a t i v e

p u l s e s t o o p e r a t e s a t i s f a c t o r i l y . The s c a l e r could 5

f u n c t i o n p r o p e r l y when i t r e c e i v e d upto 2x10 p u l s e s

p e r second. 2hQ o u t p u t of the s c a l e r was a m p l i f i e d and

i t o p e r a t e d t h e mechanica l r e c o r d e r ,

ajhe n e g a t i v e v o l t a g e of ahout - 900 v o l t s

which was a p p l i e d a t t h e ca thode of t h e G-M c o u n t e r s was

t a k e n from Miniaax type Eveready dry b a t t e r i e s . I h e u n -

r e ^ i l a t e d D-C v o l t a g e of about 200 v o l t s was p rov ided

by a l k a l i c e l l s and t h e r e g u l a t e d •¥& v o l t a g e s , t o a l l

the e l e c t r o n i c c i r c u i t s ment ioned above were s u p p l i e d

th rough a v o l t a g e r e g u l a t o r t u b e .

2 . 5 mOTOQUABElC AafiAHGMDHf

f h e pho tog raph ic ar rangement i s shown i n jPig.9«

HhQ f o u r t e l e p h o n e c a l l r e c o r d e r s as wel l as t h e watch

and d a t e arrangement were f i x e d i n a wooden box. At one

end of t h i s box, t h e 55 mm. cgaiera was a t t a c h e d . Four 6

v o l t s b u l b s were f i x e d i n s i d e t h e wooden box t o p rov ide

the f l a s h fo3^ the p h o t o ^ a p h . Every hour t h e b u l b s were

l i g h t e d and a photograph of the r e c o r d e r s , watch and the

R E L A Y - I

TO MOTOR

CLOCK

RELAV-2

TO FLASH BULB 6V.

6V. BATTERY

TO M O T O R

o o o o o o e o CAMERA

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FIG.9 P H O T O G R A P H I C ARRANGEMENT

22

d a t e was t a k e n . A f t e r f i v e minu te s t h e f i l m was wound

by a motor b r i n g i n g a f r e s h frame i n p o s i t i o n r eady f o r

t h e nex t exposu re .

f h e c lock waa c o r r e c t e d each day wi th the

Greenwich t ime s i g n a l r e l a y e d by jy.1 I n d i a Radio .

2 3

DIUHHAt VARIATION OP COSMia«RAY MBSOH

I n r e c e n t y e a r s r e a l i s a t i o n l ias grovm t h a t

accumiilat ioi i o f d a t a on t ime v a r i a t i o n of cosmio-ra^

i n t e n s i t y and i t s i n t e r p r e t a t i o n o a tiie b a s i s of

e l e c t r o d y n a m i c s and p l a s a a p h y s i c s i s an ex t remely

u s e f u l branch of stmdy, The s tudy of t ime v a r i a t i o n

of coamic- rays i a an e l e g a n t and ex t remely s e n s i t i v e

t o o l f o r p r o b i n g t h e e l e c t r o m a g n e t i c c o n d i t i o n s i n

t h e v i c i n i t y of t h e e a r t h and the sun, i n i n t e r p l a n e t a r y

space , and i n the ga l axy .

I t i s r e p o r t e d i n l i t e r a t u r e t h a t t h e d a i l y

v a r i a t i o n of cosmic- ray i n t e n s i t y i s compl ica ted by a

s u p e r p o s i t i o n of m e t e o r o l o g i e s and s o l a r e f f e c t s .

5?hecosmic-ray d a t a from i o n i s a t i o n chambers and c o u n t e r

t e l e s c o p e s a re d i f f i c u l t t o c o r r e c t f o r m e t e o r o l o g i c a l

e f f e c t s * However, t he d i r e c t i o n a l measurements of s o l a r

d i u r n a l v a r i a t i o n of coamic - rays , made by Malmfors (1949)^

and E l l i o t and Dolbear (1951) demonst ra ted c o n c l u s i v e l y

t h a t a s u b s t a n t i a l p a r t of t he obse rved v a r i a t i o n i s o f

non-meteoro logLcal o r i g i n . Ihey sugges ted t h a t an

a n i s o t r o p i c d i s t r i b u t i o n of pr imary c o s m i c - r a y s , o u t s i d e

t h e i n f l u e n c e of t h e geomagnetic f i e l d s , might be

1 . K.G. Malmfors , T e l l u s , i , 55 (194-9).

2 . H . E l l i o t , and D.W.H. Dolbear , J .Atmos. l e r r . P h y s . I , 205, ( 1951 ) .

24

r e s p o n s i b l e f o r t h i s s o l a r di iarnal v a r i a t i o n . Burnberg 3

and Da t tne r (1954) s u b s t a n t i a t e d t h i s s u g g e s t i o n .

$he r e s u l t s o f E l l i o t and Eothwel l (1956)^

and P a r s o n s (1959)^ c a s t c o n s i d e r a b l e doubt on t h i s

p r o p o s i t i o n , However, t h e r e c e n t work of E l l i o t (1960)^

and Que^by and f h a m b y a h p i l l a i (1960)'^ h a s shown t h a t

t h e l e a r l i e r r e s u l t s of E l l i o t and Rothwel l and Pa r sons

can s a t i s x a c t o r i l y be accounted f o r i n terms of an .

e x t e r n a l a n i s o t r o p y of t h e p r i m a r i e s i f an a p p r o p r i a t e

c o r r e c t i o n i s a p p l i e d to t h e c o a a i c - r a y d a t a f o r t h e

d a i l y v a r i a t i o n o f a tmospher ic t e m p e r a t u r e . Hence, t h e

e x i s t e n c e of t h e d a i l y v ^ i a t i o n of cosmic- ray i n t e n s i t y

i s now u n i v e r s a l l y acknowledged, a l though t h e obse rved

v a r i a t i o n a t a ea l e v e l and a t mounta in a l t i t u d e s measured

by i o n i z a t i o n chambers and coun t e r t e l e s c o p e s i s l e s s

t h a n 15 of t he i n t e n s i t y .

Eecent advances i n the knowledge of t h e

r e l a t i o n between changes i n t h e pr imary and secondary

components { c a l l e d c o u p l i n g c o n s t a n t s o r s p e c i f i c y i e l d

f u n c t i o n s ) h a s g iven t h e s tudy of d i u r n a l v a r a i t i o n an

3 . E.A. Burnberg, iind A .Da t tne r , Mel ius , 6 , 73, and 6 , 254,. ( 1954 ) . ^^ ^

4 . H.El l iot , - - -and P .Ho thwe l l , P h i l Ma^. 669 (1956 ) . 5 . N.B. P a r s o n s , Aus t . - J . P h y s . , I S , 462 ( 1 9 5 7 ) . 6 . H. E l l i o t , P h i l . Mag., i , 601, ( i 9 6 0 ) . 7 . J . J . Quenby, and T. I h a m b y a h p i l l a i , P h i l . Mag. 585(1960

2 o

added impor tance i n t h e sense t h a t i f \r.e knoif t h e

d i u r n a l v a r i a t i o n of d i f f e r e n t components a t one p l a c e

or t h a t of t h e same component a t d i f f e r e n t l a t i t u d e s ,

we can f i n d ou t t h e changes i n t h e pr imary spectrum

r e s p o n s i b l e f o r t h i s v a r i a t i o n (Doriaan 1957)*®

3 . 0 1 CORRBO-IION gpH MEIEQ&QLOGIGAI. gACSORS

She d a t a of meaon i n t e n s i t y c o l l e c t e d f o r

e l e v e n months a t Gulmfetrg have been ana lysed .

I t i s neces sa ry to c o r r e c t t h e d a t a l o r

m e t e o r o l o g i c a l changes s i n c e meson i n t e n s i t y v a r i a t i o n s

a r e caused fey such f a c t o r s . 2!he e f f e c t of m e t e o r o l i g i c a l

changes h a s heen s t u d i e d by many workers hu t t h e most

i m p o r t a n t c o r r e c t i o n i s r e l a t e d to change i n p r e s s u r e .

I h e i n t e n s i t y a f t e r c o r r e c t i o n may be vvr i t t en ,

I^ssI-^Ap, , fthere I i a u n c o r r e c t e d i n t e n s i t y ,

i s t h e p r e s s u r e c o e f f i c i e n t and p i s t he change i n

p r e s s u r e , f h e v a l u e of ^ could no t be de termined f o r

Gulmarg b e c a u s ^ f t h e absence of r ad iosonde d a t a , but

a va lue of —»• 0 . l 6 ^ per mb. f o r t h i s l a t i t u d e h a s been

g e n e r a l l y accep ted by o t h e r workers and t h e same h a s been

used h e r e , f h e f a c t o r a p may be w r i t t e n as ( p - p ) , where

p i d t h e observed p r e s s u r e and p i s t h e average p r e s s u r e

f o r the month.

S . L I . D o r m a n , Cosn lc - r ay v a r i a t i o n (1957) ,

2 6

5 .02 HA&MOMC AIJALYSIS

She harmonic a n a l y s i s of t h e d a t a h a s been

c a r r i e d ou t t o examine t h e phase and ampl i tude of t h e

f i r s t and second harmonics with t h e h e l p of t h e twelve

b i h o u r l y v a l u e s . These two harmonics a r e a l so termed

" d i u r n a l " and " s e m i - d i u r n a l " waves, and t h e i r "phases"

mean t h e hotxr of t h e maxima of t h e two waves.

3 .03 SggDY WISH THE CUBICAL mESCQPE AT flULMARg

Diurna l v a r i a t i o n of meson c u b i c a l t e l e s c o p e

d a t a c o l l e c t e d a t GulmaTg h a s been s t u d i e d ove r t h e p e r i o d

Pebi*uary, 1958 t o January 1959. The f i r s t and t h e second

harmonic components of meson i n t e n s i t y a f t e r app ly ing

p r e s s u r e c o r r e c t i o n s , a t Gulmsrg^X =24.7°H, 9000 f t . )

f o r d i f f e r e n t months , a r e g iven i n Table 1 . I n appendix

1 , t h e complete d a t a f o r t h e month of November 1958 i s

g i v e n t o g e t h e r wi th t h e d e t a i l s of c o r r e c t i o n f o r p r e s s u r e ,

and of harmonic a n a l y s i s . The changes i n the f i r s t and

the second harmonic components a t taulmarg a re a l s o shown

wi th t h e h e l p of t h e harmoiaic d i a l r e p r e s e n t a t i o n i n

P i g . 10 & 11 . The equipment f u n c t i o n e d e r r a t i c a l l y d u r i n g

A p r i l 1958 due to t r o u b l e with b a t t e r i e s and hence d a t a

f o r t h i s month h a s been exc luded .

Table 1 and F igure 10 show xhat t h e d i u r n a l

ampl i tude and phase of t h e meson i n t e n s i t y do no t e x i b i t

any r e g u l a r v a r i a t i o n over a p e r i o d of 11 months from

27

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A- FOff THe /yror/THi CO/^Cf/rfteD.

28

Feb* 1958 to J a n . 1959. However, ixi t he ffionths of

March and November, 1958, and J a u u a r j 1959 t h e r e appea r s

t o be a s i g n i f i c a n t change i n the amiplttude. QJhe

ampl i tudes of the d iu i 'na l component i n t h e months of

March, November and Janujary a re 0.545" and 0.52Jb

r e s p e c t i v e l y . Al l t h e s e v a l u e s f a l l i n w i n t e r . For

the^rest of t he months t h e aiapliludeti of t h e d i u r n a l

component a re aimoot c o n s t a n t ( ave rage va lue ^ 0 . 2 4 ^ ) .

The phase of the d i u r n a l component, i n the l a s t two

months (Nov. and Dec. 1958) i s markedly d i f f e r e n t from

t h a t i n t h e r e s t of t h e y e a r ,

The ampl i tudes and p h a s e s , of t h e a e m i - d i u r n a l

component a l s o do no t show any r e g u l a r v a r i a t i o n over

t h e p e r i o d of 11 months s t u d i e d . Here a g a i n the ampl i tude

and phase show a f a i r cons tancy th roughou t t h e s e months,

except f o r the phase d u r i n g March and December 19^-8,

The a p p r e c i a b l e change i n the ampl i tude and

phase of the d i u r n a l component of meson i n t e n s i t y observed

i n w in t e r months may be due to the seasona l change i n

a i r t empe ra tu r e a t v a r i o u s i s o b a r i c l e v e l s .

3 .04 SItJPY VilTH gELBSGOPgS OF DIFFERENT APBRTURE3 AT GULMARG i-

The l a r g e ampl i tudes of t h e s o l a r d i u r n a l

•f These f a c t s have been r e p o r t e d i n t h e a u t h o r ' s paper " J o u r n a l v a r i a t i o n of cosmic- ray i n t e n s i t y a t Gulmarg", P r o c . N a t i o n a l , Aced. S c i . , I n d i a , J i , , Sec, A, P a r t I , 53 (1964) .

29

v a r i a t i o n of mesoa i a t a n s i t y observed i n na r row-ang le

t e l e s c o p e s by t h e Japanese group and o t h e r workers^

encouraged u s t o per form t h i s t ype of s tudy a t t h e

middle l a t i t u d e s t a t i o n , Gulmarg, wi th d i f f e r e n t

narrow angle t e l e s c o p e s . I h u s , a t Gulmarg d u r i n g

t h e y e a r 1958 d i u r n a l v a r i a t i o n of meson i n t e n s i t y

was s t u d i e d u s i n g i n a d d i t i o n to t h e c i b u c a l meson

t e l e s c o p e t h r e e narrow angle t e l e s c o p e s h a v i n g

s emi -ang le s of 4 ° , 7° and 14.5® i n t h e H-S p l a n e and

a semi-angle of 45® f o r each i n t h e £-W p l a n e . The

d a t a a r e c o r r e c t e d f o r ba rome t r i c p r e s s u r e f o r each

month acco rd ing t o t h e method d i s c u s s e d i n s e c t i o n 3 . 1 .

For each day t h e d a t a were smoothed by takcing t h e

moving ave rages over t h r e e c o n s e c u t i v e b i h o u r l y v a l u e s ,

t heave rage v a l u e be ing t h u s c e n t e r e d a t t h e midd le h o u r .

By t h i s method e r r o r s were minimised , f h u s , t h e j f i n a l

v a l u e s a r e o b t a i n e d by adding t h e s e smoothed v a l u e s

f o r the same b i h o u r l y i n t e r v a l s f o r a l l t h e days from

Feb. t o Pec . 1958. P e r c e n t a g e d e v i a t i o n s from t h e mean

a r e p l o t t e d i n F i g . 12 , and t h e cu rves o b t a i n e d a r e

f a i r l y smooth.

She v a r i a t i o n of t h e ampl i tude £uid t h e phase

measured wi th d i f f e r e n t na r row-ang le t e l e s c o p e s i s

g i v e n i n Table 2 . The ampl i tude and t h e phase oT t h e s e

Ti V.Sarabhai and Nerurlcar, Ann. Rev. Nuclear Sc i , 6 , 1 , ( 1 9 5 6 ) .

CM I

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30

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31

components a re a l s o r e p r e s e n t e d on t h e harmonic d i a l

i n F i g . 13 .

A comparison of t h e r e s u l t s g iven i n Table 2

a s observed with d i f f e r e n t t e l e s c o p e s , b r i n g s t h e

f o l l o w i n g f a c t s to l i ^ t t

She ampl i tude o:l^th8 d i u r n a l v a r i a t i o n becomes

l a r g e r a s t h e a p e r t u r e of t h e t e l e s c o p e s becomes s m a l l e r .

However, t h e d i f f e r e n c e between t h e divirnal ampl i tude

f o r t e l e s c o p e s of and 7® i s not very s i g n i f i c a n t .

j|2i She ampl i tude of t h e s e m i - d i u r n a l v a r i a t i o n

f o r t h e 4® t e l e s c o p e i s much l a r g e r t h a n t h a t of t h e

o t h e r t e l e s c o p e s . Apart from t h i s , no g r a d u a l i n c r e a s e

wi th t h e dec r ea se i n a p e r t u r e i s n o t i c e d .

She phase of t h e diurneO. v a r i a t i o n s h i f t s

r e g u l a r l y tov?ards l a t e r h o u r s d u r i n g t h e day a s t h e

a p e r t u r e of t h e t e l e s c o p e i n c r e a s e s .

| 4 j Ifii® phase of t h e s e m i - d i u r n a l v a r i a t i o n a l s o

i n c r e a s e s wi th t h e a p e r t u r e of the t e l e s c o p e .

5 .05 DAY 20 DAI CHAHGES IM m s DIURHAL VASIATIOH OP CQSMIQ JiAY MESQM IM'X'JjiMsffir

I t i s impor t an t to examine t h e d i s t i n c t i v e

forms of t h e d a i l y v a r i a t i o n t h a t occur on i n d i v i d u a l

days i n o r d e r t o g ive a p h y s i c a l i n t e r p r e t a t i o n of t h e

M£SO/v /NTifi/S/r/

"X

Mtio/^ *

r/c Of^t. s sMOh/fAfc rf,-e f/^s r ^ secc/vc f- ^^AfoA^/e s

c<.itftecr£0 /i^rsoff t/^rfA/j/rv o^

32

s o l a r a n i s o t r o p y of c o s m i c - r a y s . O f t e n , however, t h e

s t a n d a r d e r r o r of expe r imen ta l d e t e r m i n a t i o n i s too

l a r g e t o pe rmi t v a l i d c o n c l u s i o n s aboat i n d i v i d u a l

days , and d a t a a r e t h e n averaged over a number of

d ^ s grouped t o g e t h e r on some c r i t e r i a , f h u s , t he day

t o day changes of t h e a n i s o t r o p y a t Gulmarg were s t u d i e d

u s i n g t h e method sugges ted by S i t t k u s ( 1 9 5 5 ) , ^ ° and

by Eemy and S i t t k u s ( 1 9 5 5 ) . ^ ^ With t h i s method, we have

made a phenomenological c l a s s i f i c a t i o n of t h r e e t y p e s

of d a i l y v a r i a t i o n observed i n meson i n t e n s i t y .

( i ) The *D* t y p e , h a v i n g mexima i n day t ime

between 0800 and 2000 h r s j ( i i ) t h e t y p e , h a v i n g

maxima a t n i g h t between 2000 and 0800 h r s . , and ( i i i )

t h e *HJ)* t y p e , h a v i n g two maxima i n a day.

•HD* type days f o r t h e 1 4 . 5 ° t e l e s c o p e have

n o t been cons ide red because the number of days of t h i s

type were very smal l and hence t h e s t a n d a r d e r r o r i s

l a r g e . She ampl i tude and phase of t h e d i u r n a l v a r i a t i o n

of meson i n t e n s i t y f o r d i f f e r e n t type of days f o r t h e

v a r i o u s t e l e s c o p e s a re g iven i n Table 3 . The c u r v e s drawn

i n P i g . 14 , show s o p e r a t e l y t h e d a i l y v a r i a t i o n f o r

d i f f e r e n t t e l e s c o p e s f o r a l l t y p e s of days .

10^ A . S i t t k u s , J .Atmos. T e r r . Phys . 1 , 8 0 , U 9 5 5 ) . 11 . B.fiemy, and A . S i t t k u s , Z . H a t u r f o r s c h , ^Qa, 172, (1955)

F/G D/9/1 OF MtSO/V frfr£A/S/TY fi-Off D W '/V^' TYPe" D^VS rO/7 . 7'. ft! -^^o *s' T£/.£SCO/>£S

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34

f h e r e s u l t s g iven i n f a b l e 3 sliow tiiat tiie

magni tude o f t h e s o l a r a n i s o t r o p y of pr imary cosmic

r e y s i s l a r g e r f o r t h e •!)« t ype d a i l y v a r i a t i o n thavi

i t i s f o r t h e and «N2>« t y p e s f o r a l l t h e t h r e e

na r row-ang l e t e l e s c o p e s f whi le t h i s i s no t so marked

i n t h e ca se of t h e c i tb ica l t e l e s c o p e . I t i s a l s o

e v i d e n t f rom f a h l e 3 l ^ a t t h e magni tude of a l l t h e

t h r e e t y p e s of v a r i a t i o n s becomes l a r g e r a s t h e a p e r t u r e

of t h e t e l e s c o p e becomes s m a l l e r . (Thus, t e l e s c o p e s of

a a a l l e r a p e r t t i r e a r e more s u i t a b l e t o s t u d ^ t h e v a r i a b l e

c h a r a c t e r of t h e s o l a r a n i s o t r o p y and i t s day tod£^

change, I h e d i f f e r e n c e of phase i n c r e a s e s a s the

a p e r t u r e i n c r e a s e s . I n t he case of t h e t e l e s c o p e ,

t he p e r c e n t a g e of occurence of *DS and »IID*

type of days i s 4 8 . 2 , 27*3» and 24 .3 r e s p e c t i v e l y .

I h i s shows t h a t the S type d a i l y v a r i a t i o n i s more

f r e q u e n t a t Gulmarg t h a n t h e o t h e r t y p e s . •

F i g . 15 shows t h e B a r t e l s diagram f o r 'H*

and 'HD* type of d a y s . Days f o r vihich t he d a t a i s

e i t h e r z ^ t a v a i l a b l e o r i s i ncomple t e a r e a l so

i n d i c a t e d on t h e diagram. I t m ^ be seen f rom t h e

• I n t h e case of n e u t r o n i n t e n s i t y a t Grulmarg Ch.\r .SaBtry ( I960) P h . D . f h e s i s A.M.U.Aligarh found t h a t t h e •!)• type d a i l y v a r i a t i o n i s more f requent j l f .

g Q D Q X

F I C .5

^ 'D' type Dtt'fS 0 '-v' TfPC D/v S

Wd TyPE OA /s „ ///COMPLETe D/i rs

/ i f l f f T E L S D t t ^ C A l / t / ^ r o K ' M D ' T Y P C D / f V S F0/fi'r£Lesc0P£

60

diagrKn t h a t t h e r e i s a tendency f o r D, H aad. ND,

t y p e s of days t o occur i n groups o f and t h i a i s more

prominent i n t h e case of *D* and 'S* type of days . I t

i s a l s o p o s s i b l e to c a l c u l a t e from P i g . 15, t h a t t h e r e

i s a tendency of 27-day r e c u r r e n c e of 'D* and 'H* type of

days .

3 .06 SEPEHDEHC^ pp j h e DIURHAL •AMJ'LITUDB ASP fflASB OH MAGHESPIC CHA&AglEE FIGURE C^.

Maiyr a u t h o r s have examined t h e changes i n

t h e d i u r n a l component a s s o c i a t e d wi th geomagnetic

d i s t u r b a n c e s . From e a r l i e r s t u d i e s , i t i s c l e a r t h a t

t h i s r e l a t i o n s h i p i s r a t h e r c o m p l i c a t e d . Th i s r e l a t i o n -

sh ip h a s been i n v e s t i g a t e d f o r t h e o b s e r v a t i o n s made

a t Gxilmarg, and t h e v a r i a t i o n i n t h i s r e l a t i o n s h i p wi th

l a t i t u d e h a s been examined by a n a l y s i n g the d a t a f o r

Ottawa ( X -57°H)» and C h u r c h i l l ( X * 70®®) • *

The r e s u l t s of t h i s a n a l y s i s have been shown

i n Table 4 , where t h e range of C^ v a l u e s h a s been d i v i d e d

i n t o t h r e e groups a s f o l l o w s t

ho% Q^ 4 0*5, average 0 , 2 0 .

medium 0 . 3 and ^ 0 . 7 , average 0 . 5 6 .

h igh C^ '^ 0 . 7 average 1 . 1 4 .

•These d a t a p e r t a C i n to t h e same p e r i o d a s t h e Gulmarg o b s e r v a t i o n s and they were o b t a i n e d wi th t h e ^ ind p e r m i s s i o n of S r . D.C.Sose.

38

According to Table 4 t h e ^ p l l t u d e of the

d i u r n a l v a r i a t i o n does not show acy s y s t e m a t i c

r e l a t i o n s h i p wi th C^ v a l u e s . However, t h e ampl i tude

of t h e d i u r n a l components f o r a l l s t a t i o n s are

g r e a t e r dur ing t h e days of low C^ t h a n dur ing t h e

days of h i ^ C^. and t h e phase of a l l s t a t i o n s i s

^ m o s t t h e same on days of low and h i ^ C^,

The above ment ioned o b s e r v a t i o n s are i n 12

disagreement wi th the r e s u l t s of Sandstrom (1955)

f o r t h e p e r i o d 1947-50, based on a s t u ^ of t h e meson

component a t Uppsale ( )v » which i s a h i ^

l a t i t u d e s t a t i o n and compares wi th Ottawa ( »57°N).

The r e s u l t s a r e , however, i n agreement with t h o s e f o r

Kodai^Canal ( X - 0 .6°S) a s r e p o r t e d by ( i ) Sarabha i and

Sas t ry (1956)^^ vd.th meson t e l e s c o p e , ( i i ) Sarabhai and

Sa tya p rakash (1960)^^ wi th n e u t r o n moni tor f o r t h e

p e r i o d 1956-57.

Table 4 and t h e g r s ^ h i c a l r e p r e s e n t a t i o n of

t h e d a t a g iven i n F i g . 16, i n d i c a t e t h a t t h e r e are two

12 . A.B. Sandstrom, T e l l u s , J, 204, ( 1 9 4 4 ) . 15 . Y. Sa rabha i , and T.S.G. S a s t r y , Under p r e p a r a t i o n . 14 . T . S a r a b h a i , and Satya Prak:ash, proft-Ind,- , -la/LM

Acad. S c i .

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38

d i s t i n c t t y p e s o f v a r i a t i o n of the d i u r n a l component

wi th magne t i c c h a r a c t e r f i g u r e * I n t h e case of

C h u r c h i l l and Ot tawa ( X «57®N), t h e v a r i a t i o n wi th C P

i s convex upwards, i ^ e r e a s i n t h e case of Gulmarg

i t i s concave upwards. !Ehe ampl i tude i s no t found t o

i n c r e a s e s y s t e m a t i o a l l y o r m o n o t o n i c a l l y wi th i n c r e a s e

i n Gp, a s found by Sekido and Kodama (1952)^^ f o r

Tokyo ( X = 25 N) whose d a t a can be d i r e c t l y compared

v/ith GtOaarg ( X * 24 .7°N) . I n t h e case of a l l t h r e e

s t a t i o n s t h e ampl i tude i s h e a t e r d u r i n g t h e days of low

Cp t h a n , i t i s d u r i n g the days of higj i C^. The phase

i s found t o remain c o n s t a n t f o r each s t a t i o n from

days of Low C^ t o t hose of h igh C^. on ly i n t h e case

of Gulmarg t h e r e i s an appa ren t anamoly s i n c e t h e

phase i n c r e a s e s very c o n s i d e r a b l y from days of low C^

t o t h o s e of medium C^, and i t resumes i t s low va lue on

days of h igh I t may be no ted t h a t t h e phase

depends on l a t i t u d e ; ^^ i t changes from 224° f o r Gulmarg

t h r o u ^ 192® f o r Ottawa to 155® f o r C h u r c h i l l , Th i s

b e h a v i o a r i s observed f o r a l l t y p e s of days .

15 . I . S i k i d o , and M.Kodama, Hept . I o n o s p h e r e , Res . Japan , 6 , 111, ( 1 ^ 5 2 ) .

I6 . i t .S .Yadav , Ra t . Acad. S c i . I n d i a , Sec. A, 33, 213 P a r t I I I , ( 1 9 6 3 ) .

39

5 .07 m s VOaLD-WIDyS CHANGES IK COStHIQ- AX MESQB MP TUMIR C0&&E1ATI0H WlTli SOLAR

Alijj fe^DMAfeHEi^I^ ACglVli'^T

S ^ s t e a a t i c s t u d i e ^ of tixe l o n g - t e r m changes

i n tile d a l l y v a r i a t i o n of cosmic- ray i n t e n s i t y whicli

a r e world-wide i n c h a r a c t e r kave been r e p o r t e d mos t ly

based on t h e d a t a r e c o r d e d d u r i n g t h e p e r i o d of minimiui

s o l a r a c t i v i t y , Shese a t u d i e e sugges t an a o i s o t r o p y

of the pr imary cosmic r a d i a t i o n xinder s o l a r c o n t r o l .

Here , the|aiBi of the p r e s e n t s tudy i s to use the d a t a

from s e v e r a l s t a t i o n s s i t u a t e d i n d i f f e r e n t l a t i t u d e s ,

and c o l l e c t e d d u r i n g a p e r i o d of maximum s o l a r a c t i v i t y ,

i n o r d e r t o throw f a r t h e r l i g h v on t h e world-wide

c h a r a c t e r of cosmic-ray i n t e n s i t y v a r i a t i o n s , and t o

e x p l a i n t h e r e l a t i o n s h i p between t h e ampl i tude and t h e

phase of t h e d i u r n a l v a r i a t i o n of meson i n t e n s i t y wi th

s imspot numbers and magnet ic c h a r a c t e r f i g u r e C^. I n

t h i s c o n n e c t i o n the monthly changes of the d i u r n a l and

s e m i - d i u r n a l components a t d i f f e r e n t s t a t i o n s d u r i n g

1958, t h e y e a r of maximum s o l a r a c t i v i t y , have been

s t u d i e d , and f a b l e 5 and 6 have been c o n s t r u c t e d .

The s t a t i o n s f o r which d a t a have been c o l l e c t e d

a r e t h e f o l l o w i n g : -

( i ) Makerere ( X » 2 ° S . , R i g i d i t y - 1 4 Bev.)

( i i ) Gulmarg (A «24.7®H., R i g i d i t y =9 .2 Bev.)

to I I w

i-o

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42

( i i i ) Ot tawa Rig ic i i ty « 1 . 7 Bev.)

( i v ) Sulphxir Mountain ( X«58®H, R i g i d i t y = 1 . 1 Bev.)

( • ) C h u r c h i l l ( X =70®H, R i g i d i t y « 0 . 5 Bev.)

( v i ) R e s o l u t e { X «83°H, R i g i d i t y » 0 Bev.)

f h e cu rves i n P i g . 17 r e p r e s e n t t he monthly ampl-

i t u d e of the d i u r n a l component of p r e s s u r e c o r r e c t e d

meson i n t e n s i t y a t s i x s t a t i o n s , t h e monthly mean v a l u e s

of C and t h e sun - spo t numbers f o r the p e r i o d 1958. .It

•The month t o month changes i n the d i u r n a l

ampl i tude f o l l o w a s i m i l a r t r e n d f o r a l l s t a t i o n s

which c o n f i r m s t h e world-wide n a t u r e of the d i u r n a l

component. Bat s t a t i s t i c a l l y s i g n i f i c a n t d i f f e r e n c e s

a re obse rved .

The g e n e r a l n a t u r e of t h e s e cu rves a t Makerere ,

Gulmarg, Sulphur Mountain, C h u r c h i l l and Be s o l u t e

shows a t h e s t a n e g a t i v e c o r r e l a t i o n with s o l a r a c t i v i t y ,

f h e v a r i a t i o n a l s o does not show any d e f i n i t e r e l a t i o n ^ i p

wi th Gp v a l u e s ( P ^ .

Y a r i a t i o n a i n t h e monthly v a l u e s of t h e phase

of the d i u r n a l component of meson i n t e n s i t y a t a l l t h e

s t a t i o n s a r e p r e s e n t e d i n F ig . 18. Comparison of t h e

cu rves f o r Makerere , Gulmarg, Ot tawa, Sulphur Mounta in ,

C h u r d a i l l and R e s o l u t e shows tht i t t h e behaviour i s

rrc / / A/z/VA/ v^/i/u/^ of 7/// f/MPi/rooi 0/ r/ff o//JffA>//7i compo-/V//V7- o r DtfffefA^T ST/7T/OA/S r/PO/*^ y/?/y/or/4fY TO D f C f / ^ B t ^ /9S8

iOV 5 fit, J M/HKKs

riffla - MmrHiy Mfm t^mues or tw tmniroof " or TM o/uMm contPONfNT rtr otrfcueNT sranOA/s fitOM Jnn n Pfc nst

43

q u i t e s i m i l a r excep t a t one o r two p o i n t s .

She behav iour of t h e phase a t Gulmarg i s

remarkahly d i f f e r e n t from t h a t a t o t h e r s t a t i o n s . I n

t h i s case» d u r i n g most of t h e months phase remains

c o n s t a n t .

f h e c o r r e l a t i o n of t h e behavioiir of t he phase

wi th s o l a r a c t i v i t y , and geomagnetic a c t i v i t y shows

the f o l l o w i n g s -

hJi-(1) At Makere^the behaviour i s n e a r l y p o s i t i v e l y

c o r r e l a t e d with geomagnetic a c t i v i t y as we l l

a s wi th o o l a r a c t i v i t y ,

(2) At Gulmarg, i t does no t seem to he c o r r e l a t e d

with geomagnetic a c t i v i t y , but i t shows a

p o s i t i v e l y c o r r e l a t e d behaviour with s o l a r

a c t i v i t y .

(3) At Ottawa t h e behaviour i s n e a r l y p o s i t i v e l y

c o r r e l a t e d wi th geomagnetic a c t i v i t y and a l so

wi th s o l a r a c t i v i t y .

(4) At C h u r c h i l l i t i s n e g a t i v e l y c o r r e l a t e d with

geomagnetic a c t i v i t y whi le i t i s p o s i t i v e l y

c o r r e l a t e d wi th s o l a r a c t i v i t y .

(5) At R e s o l u t e i t r e v e a l s a p o s i t i v e c o r r e l a t i o n

wi th geomagnetic a c t i v i t y , a s we l l a s wi th s o l a r

44

a c t i v i t y - but f o r a s h o r t p e r i o d i n t h e

beg inn ing .

From t h i s comparaJ t ive s tudy i t appeal 's

t h a t t h s phase of t h e d i u r n a l component i a p o s i t i v e l y

c o r r e l a t e d wi th s o l a r a c t i v i t y a t a i l l a t i t u d e s ,

( f a b l e 7 , column 2 ) , ishich shovss t h e world-wide

c h a r a c t e r of t h e phase of the d i u r n a l component of

meson i n t e n s i t y .

I t would appear from Sable 7 column 1 ,

t h a t t h e r e i s no c o n s i s t e n t c o r r e l a t i o n between

phase and geomagnetic a c t i v i t y a s i n d i c a t e d by t h e

world-wide i n d e x C^. I t would p e r h a p s be f r u i t f u l

t o see i f t h e c o r r e l a t i o n wi th l o c a l C^ v a l u e s would

be p o s i t i v e .

5 . 0 8 a?E£ AMPLITUDE AHD THE PHASE OF fHE DIURNAL VARIAI'IOH.

The hour of maximum (phse) of t h ^ d i u r n a l

component depends upon t h e d e f l e c t i o n s u f f e r e d Dy t h e

charged p r i m a r i e s from the sun i n t h e geomagnetic

f i e l d , T h e r e f o r e , t h e world-wide n a t u r e of t h e l o n g -

term changes i n phase may be a t t r i b u t e d t o change i n

the energy spec tmai o r i n t h e r a t i o of t he p o s i t i v e

to n e g a t i v e p a r t i c l e s of t h e r a d i a t i o n which p roduces

a n i s o t r o p y .

I I

1 % Bi

O * •H » 4» 0 S> Xt

o cQ

+ » ©

'H

O >» o > •rl-H cS o

r-i <3 ® S ^ O H O O m m xitt

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a • +» >» •H at

p j •H c

•H O + + as

g) H ^ o a ^ H u o a o

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• H •

<D • r-( o « eio m •H HP o « H (d s i

•H & o r4 •P o OJ o OJ +» - a g +» •P 3 •ct OQ

0 5 o o

45

P a r a o a s and f e n t o n a l s o observed, a c o u s i -VJ

s t e n t phase l a g i n l o c a l t ime of 3 to 4 h o u r s a t Hanson

( X =73®S) r e l a t i v e t o Hobar t ( X « 52°S) . They

e x p l a i n e d t h a t t h i s phase l a g i s not due to a t iaospher ic

i n f l u e n c e , b u t t h a t i t i s due to the primary p a r t i c l e

a n i s o t r o p y o u t s i d e t h e e a r t h * s magnet ic f i e l d , and

a l s o due to t h e d i f f e r e n t d e f l e c t i o n s s u f f e r e d by t h e

charged p a r t i c l e s i n a r r i v i n g a t two d i f f e r e n t s t a t i o n s .

Daring the p e r i o d of low sun-apo t a c t i v i t y , 13

Sarabhai and &ane (1953) ooserved a world-wide

r e l a t i o n s h i p between changes i n t h e ampl i tude and

phase of t h e d i u r n a l component of meson i n t e n s i t y

and they found a p o s i t i v e c o r r e l a t i o n between t h e two.

S h i s shows t h a t the i n c r e a s e of ampl i tude i s a s s o c i a t e d

with t h e s h i f t i n g of phase towards l a t e r h o u r s .

We have a l s o examined t h i s type of world-wide

n a t u r e i n t h e changes between phase and ampl i tude of

the d i u r n a l component of meson i n t e n s i t y a t t h e s t a t i o n s

under s tudy d u r i n g t h e p e r i o d of maximoai sun-apot

a c t i v i t y , by c o n s i d e r i n g the monthly mean v a l u e s of

1 7 . K.H. P a r s o n s , and A.G.Fenton, Huovo. Cimento, (Supplemento) , 8 , Se r . 10 , 311, ( 1958 ) .

18 . V .Sa rabha i , and R.P . Kane, Phys . Rev, 204, (1953)? Phys . Eev, 688 (1953) ; and Ha ture , 171 .122(1953) .

t h e phase and t h e ampl i tude .

From I I g . 19» i t i s c l e a r t h a t t h i s

c o r r e l a t i o n i s n e g a t i v e , which a£,ain c o n f i r m s t h e

world-wide c h a r a c t e r of t he d i u r n a l v a r i a t i o n .

3 .09 iiiHiiiE&Y OF gMii DIURHAL YAiilAlEIQH

I n o rde r t o i n v e s t i g a t e t h e dependence of

t h e d i u r n a l v a r i a t i o n 016 mean pr imary p a r t i c l e energy ,

we s e l e c t e d t h e meson i n t e n s i t y d a t a r e c o r d e d a t

Makerere , Ot tawa, Ghi i rch i l l and R e s o l u t e where t h e

c u t - o f f r i g i d i t i e s a re 14 Bev . , 1 . 7 Bev . , 0 . 5 Bev. ,

and 0 Bev. r e s p e c t i v e l y .

The geomagnetic f i e l d p r e v e n t s pr imary cosmic

r a d i a t i o n s of r i g i d i t y 4 14 Bev, f rom r e a c h i n g t h e t o p

of t h e atmosphere near t h e equa to r ( X » 2 ° S ) . Thus

a l o w - l a t i t u a e meson moni tor i s s e n s i t i v e t o p r i m a r i e s

of r i g i d i t y 14 Bev. The geomagnetic cut o f f

d e c r e a s e s with i n c r e a s i n g l a t i t u d e s , u n t i l a t h i ^

l a t i t u d e s (57|[) p a r t i c l e s o f r i g i d i t y 1 . 7 Bev can be

d e t e c t e d by a meson moni tor p laced t h e r e . Thus by

comparing t h e ampl i tude of the d i u r n a l v a r i a t i o n a t

d i f f e r e n t l a t i t u d e s , energy dependence can be examined.

The monthly mean v a l u e s of t h e d i u r n a l

a a p l i t u d e a t d i f f e r e n t l a t i t u d e s were g i v e n i n Table 5

k

t tf r//i riMf'tiniDi '•f\\y / • / " ' » / //•// O/UMM^L coAf/'OA/if^r o^

PfffiSUHf C O A ' t i , ; / > A// i f A' /-V/^-A/i/.' K fft O t f f / i t i M l ST/9T/OA/S

47

The r a t i o 'R ' t a b i i l a t e d i n Table 8 , i e t he

monthly mean va lue f o r a s t a t i o n monthly mean va lue f o r Mekerere

Ow Average v a l u e s of R shown Table 8 , a r e p l o t t e d

A a g a i n s t t h e r i g i d i t y a t d i f f e r e n t l a t i t u d e s i n P i g . 2 0 .

Th i s shows t h a t t h e ampl i tude of t h e d i u r n a l v a r i a t i o n

of meson i n t e n s i t y a s wel l a s the monthly changes i n

t h e d i u r n a l ampl i tude a re energy dependent .

3 .10 SMI-raLURHAL m i A g l O g 03? ISTBSSITY

For t h e s tudy of t h e s e m i - d i u r n a l v a r i a t i o n

of meson i n t e n s i t y a g a i n d a t a o f Makerere* &ulmarg»

Ot tawa, Sulphur Mountain, C h u r c h i l l and R e s o l u t e a r e

u s e d . Monthly mean s e m i - d i u r n a l ampl i tude and phase

a re c a l c u l a t e d . Only t h o s e days i n a month a re used

f o r which a l l t h e 12 b i h o u r l y v a l u e s a re a v a i l a b l e .

The ampl i tude and phase of the s e m i - d i u r n a l component

a t d i f f e r e n t l a t i t u d e s i s g iven i n Tab le s 9 & 10 .

From Table 9 , i t i s c l e a r t h a t t h e a m p l i t u d e s

of t h e s e m i - d i u r n a l component a t a l l s t a t i o n s a r e q u i t e

s i g n i f i c a n t ( > 3 <r ) , i n a l l t h e d i f f e r e n t months ,

only a t R e s o l u t e the average va lue ^

i 8

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CM o CM m GO I-I Ift CO m r-l <0 H<M t<%<OvO 0%<X)<N S KNH Or-lf-tCVJCMHOr4HOr4r4

<=1- c^cj la cr>c\i irv 00 vo irvcvi tA\ot<-»'si-iA I I I f • • • • • • • • C Jr HK «tf'<M CM H

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49

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tr\ NO \o tfN K\ oi e^ e - j T i o CM o o o o o o o o o o o o o o o o o o o o o o o o o o

H H •H

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00 00 CO oo f (0«^^ -ooo^^t^^cM<Mo • • • • • • • • I o o o o o o o o I I I iH o

cne-- CM o H <0 c y v C M v i j OHHrHHOHCM r4 •

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50

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00 VO KWO <M t-r-l 00 4AO snuN t t i

OKNO HrHf-fr-IO t i l l iH HHH t-i

I CVitT* O O O CVI ITi r-»

CM H CM ^ <0 o o ca t*-<rico • •<• • • • • • • • • • m •«(»• CM to lA ^

® • • ® • • 6) <0 S S ® O O S H > o d 0 ® O o ^

$u to • • 3 psi H 3 ft o -H G

51

0 . 0 4 i 0.02?i i s l e sB t h a n 5 ^ and hence I s no t

s i g n i f i c a n t , a l though i n some a o n t h s i t i s s i g n i f i c a n t .

At Gialmargf t h e seai-ci iuri i ial coiaponent i s

a l s o s t u d i u a by a n a l y s i n g the d a t a ot t h r e e narro\v-

a a ^ e t e l e s c o p e s hav ing semi -ang le of 4°, 7° and 1 4 . 5 °

i n t h e K-S p l a n e and the r e s u l t s a r e g iven i n I 'able 2 .

Th is f a b l e shov/s t h a t f o r the 4° t e l e s c o p e t h e a e a i -

d i u r n a l componeni; i s %uite s i g n i f i c a n t and i t i s l a r g e

aa compared t o t h e 7° and 14.!?'^ t e l e s c o p e s . Ihe phase

isa of t h e s e m i - d i u r n a l component i n c r e a s e s with t h e

a p e r t u r e of t h e t e l e s c o p e .

3 . 1 1 THE RELATIOUSBIS 3ETWEEH SEfeai-DIPfiUM. YARIATIOS AND SEOMAGH^nC lESTURBAIiCES.

Table 11 g i v e s t h e ampl i tude and phase of

the semi -d i i i rna l component of meson i n t e n s i t y f o r t h r e e

v a l u e s of C - i . e . low medium ( 0 . 5 < 0 < 0 . 7 ) P P P and h i ^ ( C ^ ^ O . ? ) .

S h i s t a b l e shows t h a t on aays of low, medium

and h i g h C^, t h e ampl i tude of t h e s e m i - d i u r n a l v a r i a -

t i o n i s cdmost t h e same ( a c c o r d i n g t o 3 < r l e v e l ) a t a l l

t h e l a t i t u d e s from 24.7°H to 83°H. But , t he phase of

t h i s component i s e a r l i e r on days of h i ^ Qp a t a l l

l a t i t u d e s abo/e 24.7®N. At 2 4 . 7 ° 5 (Gulmarg) t h e phase

of the s e m i - d i u r n a l v a r i a t i o n i s t he same on days of

52

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p) • •«•» O "Ct « to to ® 4» o a -H •B<N cd a.o H

K5-M O d jS^ ® CO ® •H M >4 <N

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) a

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a

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t ssi

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r4 O

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09

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53

medium and low U^, whi le i t i s e a r l i e r on days of Mgn. C by about one noi i r . IheBe r e s u l t s i j ad i ca t e

P t h a t r a p i d v a r i t t t i o n s i n t h e d i u r n a l component produce

v a r i a t i o n a of seiai- .diurnal componejit wi th r e s p e c t to

C . 2 h i s was sugges ted by Sarabna i and Sa tva Prtikaah P (1960)^^ , Table 11 a l so shows t h a t the ampl i tude and

phase of t h e sen i -d ix jxna l v a r i a t i o n does not show any

s y s t e m a t i c r e l u t i o n s i i i p with G^ v a l u e s a t any l a t i t u d e s .

3 .12 MOHm TO MOSm CHASGBS IK THE AMPLITUDE Abfl3 PHA3£ Of TEE S£MI~DIU&MAL OOMPOWENT AHS gHBlR &£LATI0N ^ITM 0 , VALUES AWFSIJH-SPOT mJMB£RS. F

The monthly mean ampl i tudes , geomagnetic

c h a r a c t e r f i g u r e G^, and r e l a t i v e sunspo t number ?

are p l o t t e d i n P ig . 21. The monthly mean t i n s of

maximoM ( p h a s e ) , C and r e l a t i v e san - spo t nuabero ^ i

a r e shown i n ? i g . 21 . The f i g u r e s f a c i l i a t e a s tudy A

of t h e i n t e r r e l a t i o n of t h e s e f a c t o r s .

I t can be seen from J i g . 21 and Table 9»

t h a t t he ampl i tude i s almost c o n s t a n t d u r i n g a l l t h e

months a t a l l t he l a t i t u d e s examined h e r e . Tn i s

i n d i c a t e s t h a t the s e m i - d i u r n a l ampl i tude i s not of a

v a r i a b l e c h a r a c t e r . From t h e n&ture of t h e cu rves i n

P i g . 21 i t i s c l e a r t h a t t he t r e n d of the d a t a i s

d i f f e r e n t a t d i f f e r e n t s t a t i o n s as r e p o r t e d by Sarabliai

19 . V .Sa rabha i , and Sa tya P r a k a s h . P r o c . I n d i a n Acad. 3 c i , 84 ( I 9 6 0 ) .

o i 02 0/

0

05

01 O!

a

02

0! o

0 2 01

A

Cp

Mlh/fit Rf

OOL f>f/iKG

RlSOl Off

O N ) r M i\ M J ) M O A f T f i - ^

2r- I^TOf^fTMY O/^ rw /y/H^^/TOOf Of THf Sf*^/- D/uarJ^L Con^A'OA'/rA/T of THi D»aY ^/f?f^J/9T/o/\/ or m£so/y i/i/TfNSiry AT OI/^fi'f^f^T STfTIOf^S.

e t . a l ( 1 9 5 5 ) ^ and Venkatesan and Da t tne r (1959)^^ .

iprom t h e cu rves shown i n F i g . 21» i t I s a l so

c l e a r t h a t the changes i n the ampl i tude of t h e semi-

d i u r n a l component a t a l l the l a t i t u d e s from 2®S t o

83°fi revesil no d e f i n i t e type (t- ve , o r - v e . ) of

c o r r e l a t i o n with s o l a r a c t i v i t y and geomagnetic

a c t i v i t y .

F i g . 22 ^ o w s t h a t t h e r e i s no s i m i l a r i t y

between the s t a t i o n s i n t h e changes i n phase of t h e

s e m i - d i u r n a l compoiaent of meson i n t e n s i t y .

Again t h e r e s u l t s a r e i n agreement witl i t h o s e 21

of V e n k a t e s ^ and Da t tne r (1959) and S a r a b h a i , Desai

and Venkatesan (1955)^^ .

f h e changes i n the phase of the s o m i - d i u r n a l

component do not show any r e l a t i o n %vith geomagnetic

a n d ^ l a r a c t i v i t y , t h e r e f o r e , they could no t be

d i r e c t l y caused by g e o m a ^ e t i c ^ d s o l a r a c t i v i t y .

One nay ssy ' t h a t t h e r e i s no ^^rid-wLde

agreaaenfc i n t h e case of t h e ampl i tude and phase of t h e

s e m i - d i u r n a l component, a s i t was i n t h e case of t h e

d i u r n a l component.

20, V.3arabhai» U.J). Desai* and D.Venkatesan, P h y s . , Eev. 1490(1955) .

21 . B.Venkatesan and A . D a t t n e r , f e l l u s , 21* 1 1 6 , ( 1 9 5 9 ) .

s ^

IT«V Sfv' NvMmies

J J 5 O O

/f U! > ,i,iu or 7M£ Sfftfl OtOfl/^m COMPOAfiMT •/•^TfA/snr /iT otrriMff^ snrto^

5 5

5 , 1 5 ORI&IH OP SOai^DlURSAL VARIATION

The s e m i - d i u r n a l v a r i a t i o n f o r t h e meson

component Ixas boan s t u d i e d p r e v i o t i s l j by E l l i o t ( 1952 ) ,

Be foand s n a i l ampl i tudes ( l e s s t h a n 0.05?^) for EuanCfcgro ( A S) , Godhavn ( A "80 H)t C h r l s t c h u r c h

( X =49®S) fcnd Cheltenham ( X«50®H), Bat o t h e r workers

have foimd q u i t e l a r g e ampl i tudes a t d i f f e r e n t l a t i t u d e s .

Rau (1959)^^ tised two d i f f e r e n ^ i z e d i o n i z a t i o n V

(Members and suspended them i n a v e r t i c a l narrow f i s s u r e

i n a rocky under 40 m e t e r s of water i n l a k e c o n s t a n c e .

Wi'Si t h i s arrangement he obse rved the s e m i - d i u r n e l compo-

nen t with an ampl i tude of 0 . 1 8 + 0.149^*. ' « o l t j e r and 23

Gropoloen (1950) u s i n g s t e l n k e - i o n i s a t i o n a p p a r a t u s

(12 cm. l e a d top s h i e l d , and 10 cm. l e a d s i d e s h i e l d ) ,

found a very s i g n i f i c a n t s e m i - d i u r n a l component with an

ampl i tude of 0.19^» maximum a t 4 h r s . (Local t i m e ) .

£au a s we l l a s W a l t j e r and Gopokoen found

t h a t the s e m i - d i u r n a l component i s n e a r l y I n phase

vCtii t h e s e m i - d i u r n a l component of t h e ba romete r io

p r e s s u r e .

22. W.Saa, Z^fhys . i M , 265 (1959)» 25. fl.a. ifSfoltjer, and Gopokoen, P h y s i c a , 112(1950) .

56

I n I n d i a , a t low l a t i t u d e s Sarabhai e t a l .

(1955) ^ s o otoserved a s i g n i f i c a n t s e m i - d i u r n a l

<^mposent and they found t h a t i t ^ o w s l ong - t e rm (Ganges.

I h e r e s u l t s p r e s e n t e d i n t h i s c h a p t e r a l s o

i^ow t h a t the se f f i i -d iu raa l v a r i a t i o n i s q a i t e s i g n i f i -

can t between the l a t i t u d e s of 2®S and 70°5, but t h a t

a t h i ^ e r l a t i t u d e s i t s v s l u e i s not l a r g e .

Rau (1940)^^ and Ehmert (1940)^^ e x p l a i n e d

laiat t he s i g n i f i c a n t semi-dixirnal component of coamic-

re^ i n t e a a i t y ^ I c h was i n phase with t h e s e m i - d i u r n a l

component of t h e b a r o m e t e r i c p r e s s u r e was due to t h e

a tmospher ic o s c i l l a t i o n s . However, t h e t h e o r e t i c a l

s tudy of S l l i o t and Dolbear (1950, 1951)^^ r e v e a l e d

t h a t s e m i - d i u r n a l v a r i a t i o n i s not due t o a tmospher i c

o s c i l l a t i o n s . Sa r abha i , Desai and Venfeatesan (1955)^®

e x p l a i n e d t h a t the s i g n i f i c a n t s e m i - d i u r n a l component

may not be of a tmospher ic o r i g i n , but t h a t i t h a s a

r e a l e x i s t e n c e .

Venkateean and Da t tne r (1959)^^ s t u d i e d i n

d e t a i l t h e l o n g - t e m changes i n t h e s e m i - d i u r n a l

v a r i a t i o n f o r Huancayo, C h r i s t c h u r c h , and Cheltenham

24. W.Eau, Z.Phys. i i 6 , 105 (1940) . 25. A.Ehmert, S a t u r w i s s , 28, 28 ( 1 9 4 0 ) . 26 . H . E l l i o t , and D.W.H. ^ I b e a r , P r o c . Phya. Soc.

157 (1950) j J .Atmos .Ter t r .Phys . i , 205(1951) .

57

f o r t h e p e r i o d (1959-52) and they found t h a t t h e

changes l a the s emi -d iu rna l ampl i tude were d i f f e r e n t

f o r t h e t h r e e s t a t i o n s . Ihey a l s o found t h a t t h e

t i m e s of maxisia of t h e s e m i - d i u r n a l v a r i a t i o n were

s i g n i f i c a n t l y d i f f e r e n t a t d i f f e r e n t l a t i t u d e s , and

t h e l o n g - t e r m changes i n t imes of maxima were not

c o r r e l a t e d wi th t h e l a t i t u d e s of t h e s t a t i o n s , f h e i r

r e a i l t s a l so show t h a t t h e r e i s no r e l a t i o n between

laie geomagnetic d i s t i a rbances { r e p r e s e n t e d lay G^) and

t h e s e m i - d i u r n a l ampl i tude .

Our r e s u l t s conf i rm t h e f i n d i n g s of yenka te san

and B a t t n e r . One may summarize t h a t s e m i - d i u r n a l

v a r i a t i o n s have been found t o have no c o r r e l a t i o n wi th

geomagnetic and s o l a r ac t iv i fcy and with a tmospher i c

changes . £hey a r e no t even found to have a world-wide

c h a r a c t e r . Under t h e s e c i r c u m s t a n c e s one m ^ e i t h e r

look f o r o t h e r phenomena of a 12 hour p e r i o d with which

s e m i - d i u r n a l v a r i a t i o n may be p h y s i c a l l y r e l a t e d , o r

one may conclude t h a t t h e e x i s t e n c e of t h e Second

harmonic component of "the d a i l y v a r i a t i o n does not

have a p h y s i c a l s i g n i f i c a n c e - i t i s on ly a ma themat ica l

f e a t u r e . Any p e r i o d i c phenomena may be ana lyzed i n t o

i t s ha rmonics , but i t i s n o t nece s sa ry t h a t each harmonic

ms^ have a p h y s i c a l r e a l i t y o r s i g n i f i c a n c e .

5 8

3 . 1 4 D I S C U S S I O N

The d a i l y v a c a t i o n of cosmic- ray i n t e n s i t y

i s g e n e r a l l y d i s c a s s e d i n terma of d i i i r n a l and semi-

d i u r n a l components, or some t i m e s , by t h e d i f f e r e n c e

between the mean i n t e n s i t i e s du r ing the day and n i g h t

h o u r s , i i t h e i t h e r method, the a n a l y s i s i s capab le

of r e v e l i n g on ly t hose changes i n i n t e n s i t y w i t h i n

24 h o u r s \'shich a re g r a d u ^ and r e p r e s e n t d e v i a t i o n s

of i n t e n s i t y ( • ve o r - v e ) , wiiich p e r s i s t f o r

s e v e r a l h o u r s .

I t i s now g e n e r a l l y b e l i e v e d t h a t t h e d a i l y

v a r i a t i o n of xhe cosmic-ray i n t e n s i t y i s due to

a n i s o t r o p y of t h e primary r ^ a d i a t i o n i n c i a e n t on t h e

e a r t h ' s a tmosphere , but i t i s no t c l e a r how t h i s

a n i s o t r o p y i s c r e a t e d . We ana lysed t h e d a t a f o r meson

i n t e n s i t y a t Makerere , Gulmarg, Ot tawa, Sulphur Mountain ,

C h u r c h i l l and Keso lu te and found a s i g n i f i c a n t ^ p l i t u d e

of t h e d i u r n a l component a t a l l t h e l a t i t u d e s from 2°S

t o I f t h e v a r i a t i o n were due to t h e s o l a r magne t i c

f i e l d , we would have got i n s i g n i f i c a n t ampl i t udes a t t h e

e q u a t o r ; on t h e o t h e r hand, i f i t were due to t h e

magnet ic f i e l d of the e a r t h , we would have got i n s i g n i -

f i c a n t a a p l i t u d e s beyond- the • 'knee". T h e r e f o r e t h e s e

r e s u l t s conf i rm t h a t t he d i u r n a l v a r i a t i o n i s due to

59

tlie a i i i so t ropy of t h e primary f l u x . Maliafora (1949)^

and E l l i o t and Boibear (1951)^ r e a c h e d the same c o n c l u s i o n

v^en they s t u d i e d the d i u r n a l v a r i a t i o n witix d i r e c t i o n a l

t e l e s c o p e s p o i n t i n g i n two d i f f e r e n t d i r e c t i o n s i n c l i n e d

e q u a l l y wilii r e s p e c t to v e r t i c ^ i

Ehmert and S i t t k u s (1951) have r e v e a l e d

the d i f f e r e n c e i n ampl i tude bet^veen t h e d a i l y v a r i a t i o n

s imu l t aneous ly measured by an i o n chamoer of o m n i d i r e c -

t i o n a l s e n s i t i v i t y and by a v e r t i c a l coun te r t e l e s c o p e

h a v i n g a more l i m i t e d d i r e c t i o n a l s e n s i t i v i t y , Sekido

e t , a l . (1950)^®*^^ iiad p o i n t e d ou t t h a t the amp l i t udes

of the f i r s t harmonic component of the d a i l y v a r i a t i o n

of CO smic-ray i n t e n s i t y becomes l a r g e r as t h e a p e r t u r e

of the t e l e s c o p e becomes s m e l l e r . These a u t h o r s based

t h e i r r e s u l t s on a s tudy by two t e l e s c o p e s 12° and 40®.

Our stucly a t Gulmarg dur ing t h e y e a r 1958, u s i n g a

c u b i c a l t e l e s c o p e and t h r e e narrow angle t e l e s c o p e s

hav ing semi-angle of 4®, and 1 4 . 5 ° i n t h e N-S p l a n e

and s ^ i - a n g l e of 45° each i n the E-1 p l ane a l s o showed

t h a t the ampl i tude of t h e f i r s t harmonic component of

t h e d a i l y v a r i a t i o n i n c r e a s e s a s t h e a p e r t u r e of t h e

t e l e s c o p e s i s r educed .

27. A. Ehmert, and S i t t k u s , A, a . H a t u r f o r s c h , ^ , 613(1951) . 28. T. Sekido, M. Kodana and T. Yagi , Hep. Ionosphe re

E e s . J a p a n , 207(1950) . 29. I . S e k i d o and S.Yoshida, Rep . Iono . R e s . J a p a n , 4 , 3 7 , ( 1 9 5 0 )

60

flae change oX ampl i tude with t h e angle of

the t o l e s c o p a s i s shovm i n K g . 25, and i t may-be

n o t i c e d t h a t t h e r a t e of change i n the ampl i tude i s

f a r f rom c o n s t a n t , f o r l a r g e a a ^ e a the r a t e of

change iTi ampl i tude i a very l i t t l e , tout f o r narrow

a n g l e s t h e change i s r s ^ i d . The g e n e r a l t r e n d of

i n c r e a s i n g v a r i a t i o n wi th nar rower a n g l e s of t e l e a c o p e a

i s e x p l a i n a b l e on the b a s i s of an ave rag ing e f f e c t .

However, i t i s s t r a n g e a t t he ave rag ing e f f e c t i s so

n e g l i g i b l e between t e l e s c o p e a n g l e s of about 16^ and

45* o r l a r g e r , a p l a u s i b l e e x p l a l n a t i o n may be t h a t

t h e incoming r a o i a t i o n h a s energy a n i s o t r o p y as we l l

a s d i r e c t i o n a l a n i s o t r o p y and d i r e c t i o n a l a n i s o t r o p y

I s mucbi l a s s s i ^ f i c a n t t h a n energy a n i s o t r o p y .

f h e r e l a t i o n of ampl i tude and phase of t h e

d i u r n a l component with t h e magnet ic c h a r a c t e r f i g u r e Cp

h a s been s t u d i e d by meanB of i o n i z a t i o n c h a a b e r s

and coun te r t e l e s c o p e s by Bhmert and S i t t k u s (1950)^®

Sefcido and Yoshida ( 1 9 5 0 ) ^ and by i a i i o t and Dolbear 2

(1951) • fiowever, ^ e r e i s no g e n e r a l agreement between

t h e r e s u l t s of t h e v a r i o u s a u t h o r s . E i r o r e t a l . ( 1 9 5 4 ) ' ^

h a v ^ ^ o ^ n t h a t the m p l i t u d e of the diarn&L v a r i a t i o n

i n c r e a s e s on ciaye of h i ^ geomagnet ic p l a n e t a r y i n d e x 50 . Sas t r j? , Ch. V. , p h . B . T h e s i s , Al igarh Muslim U n i v e r s i t y ,

A l i g a r h ( I n d i a ) , I 9 6 0 . 31 . J . A . f i r o r , W.H. l o n g e r , and J .A .3 impson ,phys .Kev ,

M . 1051 ( 1 9 5 4 ) .

6

K^ and t h a t t he I n c r e a s e i n ampl i tude i s not caused

by a change i n t h e geomagnetic f i e l d , S i t t k u s (1955)^^

0 n t h e o t h e r hand found t h a t days of i a r g e amp l i t udes

were not always a s s o c i a t e d wi th l a r g e v a l u e s .

Sogg (1949)^^ found t h a t t h e phase of t h e d i u r n a l

V a r i a t i o n was e a r l i e r on m a g n e t i c a l l y d i s t i i r b e d days

t h a n t h a t on q u i e t days , but t h e ampl i tude remains

c o n s t a n t . Ramanathan (1956)^^ a t low l a t i t u d e s

( X «13®5) obse rved t h a t t h e d i u r n a l ampl i tude was

more on days of h i ^ G^ v a l u e s t h a n t h a t on days of

low C v a l u e s . Host of t h e s e r e s u l t a re based on P

t h e d a t a c o l l e c t e d b e f o r e 1954. Owing t o t h e low

c o u n t i n g r a t e of most of t he i n s t r u m e n t s i n u s e a t t h a t

t ime the l i m i t s of e r r o r were c o n s i d e r a b l e . I h u s i t

was wor thwhi le t o perform t h i s s tudy a g a i n i n a more

s y s t e m a t i c w ^ a t d i f f e r e n t l a t i t u d e s wi th i n s t r u m e n t s

o f h i ^ coun t ing r a t e . I h i s o p p o r t u n i t y was p r o v i d e d

by t h e I . G . Y . programme, and t h e d a t a i s , t h e r e f o r e ,

c o n s i d e r e d s t a t i s t i c a l l y more r e l i a b l e .

5 . 15 BXPLAamOS OF mgafiAL YAElAiglQH

She t h e o r y of t h e d i u r n a l v a r i a t i o n of c o a » i c

r ^ s i n te rms of t h e magne t i c f i e l d of t h e sun a s

32. A.E.Hogg, J .Atmos l e r r . Phys . i , , 114 (1950) j J .Atmos T e r r . P h / s . 1, 56(1950) .

33. K.Hamanathan, P r o c . I n d i a n , Acad.Sci .Vol .XLIV,Ho.5 Sec. A, 307 (1956 ) .

62

sugges ted by Janossy (1957)^^ p r e d i c t s t h a t t h e

ampl i tude of t he d i i i rna l component should change

v^th l a t i t u d e , Ees ia l t s of t h e s t a t i o n s we have

ana lysed i n Ch. lY do not show t h e s imple l a t i t u d e

dependence p r e d i c t e d by J a n o s s y . V a l l a r t a and

Godart (1959)^^ and more r e c e n t l y S inger

have shown t h a t t h e r e wo\ild be no s o l a r d i u r n a l e f f e c t

dae to t he magne t ic f i e l d a t the s u r f a c e of t h e sun

f o r p a r t i c l e s of energy g r e a t e r t h a n 9 Bev. Again

we have observed d i u r n a l v a r i a t i o n atA»20s i-®-

f o r p a r t i c l e s of energy g r e a t e r t h a n 14 Bev. P i r r o r 37

et^ a l . (1954) observed the dixirnal v a r i a t i o n f o r

nesatron i n t e n s i t y even a t t h e equa to r i . e . f o r

p a r t i c l e s of energy g r e a t e r t han 15 Bev. Our r e s u l t s

t o g e t h e r 'svith t h e ev idences produced by o t h e r a u t h o r s

show t h a t Janossy* s t heo ry i s u n t e n a b l e , 38

Jfagashima (1955) h a s ejcamined t h e p o s s i o i l i t y

of e x p l a i n i n g a d i u r n a l v a r i a t i o n of the o r d e r of

0 , 2 to 0.53^ on the b a s i s of ah e l e c t r i c f i e l d t h e o r y . i 2 h i s t heo ry a l s o p r e d i c t s ^ ^ g e l a t i t u d e dependence

34 . L . J a n o s s y , Z.Phys. 10^, 430 (1937) , 35. V a l l a r t a , M.S. and G o d ^ , 0 . , Rev. ffiod.Phys.iJ,,

180(1939) . 36. S . F . g i n g e r , P r o g r e s s i n Elementary p a r t i c l e

and Cosmic-ray phys . V 0 I . 4 , 503(1958) . 37 . F i r o r , e t / . a l . , Phys . Eev. 1031(1954) . 38. K.Kagashims, J.Geomag. Geoe lec t . J , 51 (1955)

63

of t h e d i u r n a l v a r i a t i o n which i s not obse rved by u s 39

or by e a r l i e r workers . Ponger (1953) h a s shown

t h a t the d iurnea v a r i a t i o n s i n cosmic- ray i n t e n s i t y

a r e not caused by t h e g e o e l e c t r i c f i e l d .

Burnberg and Da t tne r (1354)^® have shown

t h a t , seen from a f i x e d c o o r d i n a t e system, t h e r o t a t i n g

sun W3uld be s t r o n ^ y p o l a r i s e d , so t h a t t h e r e would

be a p o t e n t i a l d i f f e r e n c e between t h e p o l e s and t h e

s o l a r e q u a t o r of t he o r d e r of 10^ v© I'fcs. The combined

a c t i o n of the e l e c t r i c f i e l d t h u s produced and t h e s o l a r

magne t i c f i e l d v?ill cause t h e charged p a r t i c l e s coa ing

from t h e ga laxy to r o t a t e with t h e sun, so t h a t t h e

e a r t h fldll r e c e i v e more p a r t i c l e s on t h e even ing s i d e

t han on the morning s i d e . I n t h i s way t a n g e n t i a l

a n i s o t r o p y i s supposed t o e x i s t . But our r e s u l t s a s

wel l a s t h o s e of e a r l i e r workers^^ show t h a t t h e t ime

of maximum of l ^ e d i u r n a l v a r i a t i o n occvirs a t noon, JO

or even b e f o r e noon. Al fven (1954) on t h e o t h e r hand ,

h a s shown the p o s s i o i l i t y of an ou t ward r a d i a l f l o w d

of energy depending on t h e a c ^ e r a t i n g p r o c e s s w i t h i n

59. W.H. Ponger , Phys . £ e v . 351 ( 1 9 5 3 ) . 40 . E.A. Burnberg and A .Da t tne r , S e l l u a , J , 7 3 ; 254,(1954) 41 . Nuovo Qlmento, 6 U^S7) " 42. H. A l fven , Phys . Eev. 1082 ( 1 9 5 4 ) .

64

t h e s o l a r system, f h l s «r l l l Impar t a r a d i a l a n i a o t r o p y

to c o a m i c - r a y s , which w i l l be changed wi th 11 -yea r

cyc l e of s o l a r a c t i v i t y . These e x p l a n a t i o n s reqvi i re

a genera l magne t ic f i e l d of t h e sun of t h e o r d e r of

10"^ ganss i n t h e r e g i o n of t h e e a r t h t o account f o r

a diurnaQ. v a r i a t i o n of the o r d e r of 0,2$>,

E e c e n t l y , on t h e b a s i s of t h e i r r e s i i l t s and

o t h e r p u b l i s h e d d a t a , E l l i o t and fiothwell (1956)^^

sugges ted t h a t t h e d i u r n a l v a r i a t i o n may be produced

by the modu la t ion mechanism o p e r a t i n g on pr imary

coanic-rfiQrs w i t h i n t h e r e g i o n of t h e e a r t h s magne t i c

f i e l d . The world-Wide c h a r a c t e r of t h e changes i n t h e

ampl i tude and phase of the divirnal v a r i a t i o n and t h e i r

c l o s e r e l a t i o n with s o l a r a c t i v i t y which we obse rved

suppor t t h i s s u g g e s t i o n ,

The f o l l o w i n g i n t e r e s t i n g f a c t s have emerged

from more r e c e n t d a t a , i n c l u d i n g our own, and a t h e o r y

of d i u r n a l v a r i a t i o n h a s t o e x p l a i n t h e s e f a c t s . The

o l d e r U i e o r i e s were propounded when i n s u f f i c i e n t f a c t s

were known and t h e r e f o r e t h e r e i s need xor c o n s i d e r a t i o n ,

m o d i f i c a t i o n o r r e t h i n k i n g .

45 . H. E l l i o t , and d . E o t h w e l l , PhiL U a g . l , 669(1956) .

65

( i ) f h e jyapl i tude and phase of t h e d i u r n a l

V a r i a t i o n changes from day t o day, and y e a r t o y e a r .

At v a r i o u s o c c a s i o n s and p l a c e s , t h e maximum may

occur a t e i ^ t ime d u r i n g t h e day.

( i i ) There a r e two t y p e s of d i u r n a l v a r i a t i o n s

one wi th maximum d u r i n g t h e day type) and t h e

o t h e r 'sCQi maximum a t n i ^ t , (B t y p e ) .

( i i i ) The *!>* and type of days occur g e n e r a l l y

i n groups of t w or t h r e e days and t l i e r e i s a 27-day

r e c u r r a n c e i n th«a .

( i v ) H e i t h e r *33* nor •H' type d i u r n a l v a r i a t i o n

h a s got any r e l a t i o n wi th geomagnetic a c t i v i t y .

(v) The phase of t h e d i u r n a l and s e m i - d i u r n a l

compomnts i n c r e a s e s wi th t he a p e r t u r e of t e l e s c o p e s .

The phase of t h e y e a r l y mean d i u r n a l component

shows l a t i t u d e dependence.

( v l i ) The phase of t h e d i u r n a l v a r i a t i o n shows a

p o s i t i v e c o r r e l a t i o n with s o l a r a c t i v i t y , wh i l e t h e

ampl i tude shows a n e g a t i v e c o r r e l a t i o n .

( v i i i ) Changes i n phase a r e n e g a t i v e l y c o r r e l a t e d

wi th 'Uie ampl i tude of the d i u r n a l component a t v a r i o u s

l a t i t u d e s .

66

( i x ) I t i s shown by Sekido and Y o ^ i d a (1953)^^

tHat the d i u r n a l ampl i tude i s markedly de te rmined

by t h e d i r e c t i o n e a s e n s i t i v i t y of t h e r e c o r d i n g

i n s t r u m e n t . The change i n ampl i tude wi th t h e semi'-

angle of t h e meson t e l e s c o p e s i s very much more

t h a n normal ly expec ted . Large amp l i t udes o f the o r d e r

of 1 - 2 p e r c e n t have been obse rved by a s as v;ell as by

e a r l i e r mxkera.

The changes i n the ampl i tude with geomagnetic

and s o l a r a c t i v i t y and the f r e q u e n t day to day changes

i n t h e d i u r n a l v a r i a t i o n , obse rved by u s , showing t h e

v a r i a b l e c h a r a c t e r of t h e a n i s o t r o p y make i t n e c e s s a r y

to e v a l u a t e t h e p h y s i c a l meaning to be a t t a c h e d t o

average a n i s o t r o p y .

The d i u r n a l v a r i a t i o n of the 'D*, 'N* and 'ID*

type iKiiich occur i n groups of days and t h e f r e q u e n t

cSianges i n t h e ampl i tude of t h e d i u r n a l component

make i t appear t h a t t h e r e may be a v a r i a b l e a n i s o t r o p y

superimposed on an average or permanent a n i s o t r o p y .

At p r e s e n t i t i s d i f f i c u l t to accep t t h e i d e a of a

permanent a n i s o t r o p y because i t s f e a t u r e s and c h a r a -

c t e r i s t i c s have not been d i s c o v e r e d . I t would appear

Ali^aUl^^ 114 ti'.

67

t h a t i t s f e a t u r e s have been masked by a more prominent

a n i s o t r o p y of a h i g h l y v a r i a b l e c h a r a c t e r .

From p r e s e n t I n d i c a t i o n t h e most f e a s i b l e

t h e o i ^ appea r s t o be one due to E l l i o t and a > l b e a r ( l 9 5 l ) «

Hagashima (1955) aa m o d i f i e d by Herurkar (1957)^^ .

Th i s theory g i v e s a p l a u s i b l e e x p l a n a t i o n of s e v e r a l

s i g n i f i c a n t f e a t u r e s of t h e d a i l y v a r i a t i o n of a e s o n

i n t e n s i t y on the b a s i s of t h e c r e a t i o n of an a n i s o t r o p y

by the p re sence of s o l a r beams of i o n i z e d m a t t e r i n

t h e nei |^)x>urhood of t h e e a r t h . These beams a re

supposed to have t r a p p e d magne t ic f i e l d d e r i v e d from

a c t i v e r e g i o n s on the s u r f a c e of t h e sun . Adopting

t h e d e n s i t y and v e l o c i t y of i o n i z e d m a t t e r i n t h e

beams c o n s i s t e n t with s o l a r geomagnetic d i s t u r b a n c e s i

and assuming a st i-ength of the t r a p p e d magne t i c f i e l d s

compat ib le with e l e c t r o ^ n ^ i c a l c o n s i d e r a t i o n s , i t

i s p o s s i b l e to d e r i v e a d a i l y v a r i a t i o n of meson

i n t e n s i t y which cou ld have a maxLmiam d u r i n g e i t h e r dqy

o r n i j ^ t h o u r s . Th is 'N' and t y p e s o f d a i l y v a r i -

a t i o n would occur i n groups of days which would have

a tendency of 27-day r e c u r r e n c e ( t h e s e f e a t u r e s were

obse rved i n our a n a l y s i s f o r 'D* and type of

d i u r n e i v a r i a t i o n a t Gulmarg). The d a i l y v a r i a t i o n

would have an ampl i tude upto Xi» on i n d i v i d u a l days .

102

The ampl i tude us we l l a s phase of each t y p e of

d a i l y v a r i a t i o n be expec ted to a l t e r dur ing

each group. There would be a p o s s i b i l i t y of d a i l y

v a r i a t i o n wilii two maxima on some o c c a s i o n s ( i . e .

'ND* type d a i l y v a r i a t i o n which was ooserved by

us a t Gulmarg), However, K u r u r k a r ' s t h e o r y does

not ssy a n y t h i n g about permanent a n i s o t r o p y of cosmio-

r ^ a .

CHAPTER IY«

LAi;i!gg]}E Am ALSlirUm OF THE DIURifAL AND SMI^mgiillAX. YAaiATIOM 01* COSMIC

RAJ III!D£HSIgY.

k s tudy of t h e l a t i t u d e dependence of the ampl i tude and piiase of the d i u r n a l v a r i a t i o n of

cosmic- ray i n t e n s i t y i s a very i m p o r t a n t t o o l f o r

u n d e r s t a n d i n g t h e energy spectrum of t h e pr imary

a n i s o t r o p y r e s p o n s i b l e f o r t h e d a i l y v a r i a t i o n .

Donaan (1957)^ h a s c a l c u l a t e d t h e energy spectrum

f o r t h e p e r i o d 1957-51 u s i n g t h e d a t a of meson

i n t e n s i t y r e c o r d e d by i o n i s a t i o n chambers.

There a re a few r a t h e r u n s y s t e m a t i c r e p o r t s

on t h e s tudy of l a t i t u d e dependence of d i u r n a l

v a r i a t i o n . Thompson (1958)^ , u s i n g t h e d a t a of

Gompton and Turner (1937)^ c o l l e c t e d on the P a c i f i c

Ocean between Vancouver and Sydney^ showed t n a t bo th

t h e ampl i tude and phase a r e approximate ly independen t

of l a t i t u a e . Thambyahpi l la i and U l i o t (1953)^ s t u d i e d

1 . L . I . , Dorman, Coamic-r^jr v a r i a t i o n ^ P u b l i s h e d by S t a t e P u b l i s h i n g House f o r Techn ica l and T h e o r e t i c a l l i t e r a t i i r e , Moscow, ( 1 9 5 7 ) .

2 . J . L . Thompson, Phys .Hev . , 95 ( 1 9 5 8 ) . 3 . A.ti. Compton, and Turne r . Pl ys. R v. <51 Whi) 4 . Thambyahpi l la i and H . E l l i o t , H a t u r e r H i , 918(1953) .

? 0

t h e d i u r n a l v a r i a t i o n , bu t they found no s i g n i f i c a n t

dependence on l a t i t u d e . F i r o r e t a l . (1954)^ ,

however, have found an i n c r e a s e i n ampl i tude v?ith

l a t i t u d e . Th i s c o n c l u s i o n i s based on t h e a n a l y s i s

of two s t a t i o n s v i z . Climax ( X » 48°H) and

Huancayo ( X » 0® ) and they found a r a t i o of.

the o r d e r of 1 . 4 + 0 . 0 2 i n t h e peak to peait v a r i a t i o n

between t h e two s t a t i o n s .

f h e a n a l y s i s of t h e d a t a of fluancs^yo (X«0® )

Cheltenham ( X t.SO^S), G h r i s t c h u r c h ( 48®S) and

Godhavn ( X » SO^N) where t h e h a r d component d a t a h a s

been averaged over e i ^ t - y e a r s , b r i n g s t o l i g h t t h e

f o l l o w i n g f a c t s » -

(1) IThat t h e v a r i a t i o n a t Cheltenham and

Chr ia t ch i i r cn , wnich a re symmet r ica l ly s i t u a t e d

with r e s p e c t to t h e ecjuator , a r e s i m i l a r and t h e

hour of maximum i s a l s o approximate ly t h e same.

(2) I h a t t h e ampl i tude of v a r i a t i o n a t Godhavn

( X »80 N) which i s s i t u a t e d near t h e p o l e i s s m a l l e r

t h a n a t t h e o t h e r t h r e e s t a t i o n s and

5 . J . A . F i r o r , W.H.Fonger, J . A . and Simpson, Phys, Jiev. 1051 (1954) ,

71

(5) t h a t t h e d i i i rna l v a r i a t i o n s a r e a p p a r e n t l y

of i r r e g u l a r c h a r a c t e r .

These da t a were of a h igh degree of accu racy ,

l e t i t i s d i f f i c u l t to draw dependable c o n c l u s i o n s

from them, because t h e s tudy i s not very s y s t e m a t i c

between t h e r e g i o n from equa to r t o p o l e i n bo th t h e

hemi - sphe re s of t h e e a r t h . Thus, i t was thought wor th -

whi le to e x t e n s i v e l y s tudy the l a t i t u d e dependence of

t h e diiurnal and s e m i - d i u r n a l v a r i a t i o n of bo th a e s o n i c

and n u c l e o n i c components of t h e cosmic- ray i n t e n s i t y .

Data c o l l e c t e d du r ing t h e I . G . I . ( J a n . t o Aug.

1958) h a s been used by u s f o r a n a l y s i n g t h e l a t i t u d e

and a l t i t u d e e f f e c t s of c o s m i c - r a y s . *e have a n ^ y z e d

t h e r e s u l t s of o b s e r v a t i o n s t a k e n a t the s t a t i o n s

shown i n Table 12 .

The s tudy has been d iv ided i n t o two p a r t s •

( i ) t he d a t a of t h e s t a t i o n s have been averaged

f o r a l l t h e a v a i l a b l e days over t h e e n t i r e

1 . 5 . x . p e r i o d . T h i s averaged d a t a have been

h a r m o n i c a l l y ana lyzed . The r e s u l t s , i . e . ,

the ampl i tude and phase of t h e f i r s t and second

harmonic components a re g iven i n Tab le s and

14.

72

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( i i ) The d a t a f o r m a g n e t i c a l l y d i s t i i rbed and qi i ie t

da^s o n l y , f o r t h e p e r i o d , have been

averaged and a n a l y s e d - s e p a r a t e l y . Th i s

s e l e c t i o n has been done to compare the

l a t i t u d e dependence on u n d i s t u r b e d days wi th

t h a t on d i s t u r b e d days .

4 . 1 LATITUDE DBfEHDJEBCE OF !CJA£ AMfLItTUl E Qg THJB JIURHAL AUD S£MI~3)IU&HAL VABIMION.

I t i s apparen t from Tab les 15 and 14 t h a t t h e

ampl i tude of t h e d i u r n a l component of meson as we l l

as n e u t r o n i n t e n s i t y does not show i n c r e a s e o r

dec rease mono ton ica l ly with l a t i t u d e . However, f o r

s t a t i o n s s i t u a t e d nea r t h e p o l e , t h e ampl i tude i s

a p p r e c i a b l y s m a l l e r t h a n a t o t h e r p l a c e s . These

r e s u l t s a r e I n agreement with t h o s e of Iielchvir (1961)^

viio found i t i n t h e case of n e u t r o n i n t e n s i t y o n l y .

The ampl i tude of t h e s e m i - d i u r n a l component

a l s o does not show any l i n e a r v a r i a t i o n wi th l a t i t u d e .

A very s i g n i f i c a n t o b s e r v a t i o n , however , i s

t h a t i n t h e case of meson i n t e n s i t y i n t h e n o r t h e r n

hemisphere , the ampl i tude of bo th t h e d i u r n a l and

6 . Lekhvi r Sud, Ph.D. T h e s i s , Pu^ao U n i v e r s i t y , Chandigarh (pb) I n d i a .

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seml-<ituriial v a r i a t i o n a t f i r a t i a c r e a s e s wi th

l a t i t u d e ! ^ |}ut t h e t r e n d i s r e v e r s e d a t about a

l a t i t u d e of 57°S. 2iie r e a s o n f o r t h i s s t r a n g e

behav iour of meson i n t e n s i t y h a s y e t to be found ,

4 . 2 LAgLÔOB BSPBSDBHCE Q? £SASB Of gHJS PlPaSAL AlfP SMI-mgHHAL YARlAflOS^

But f o r (Julmarg (2700 m e t e r s ) and Makerere

(1196 M e t e r s ) , a l l s t a t i o n s o f Sab le 12 a r e s i t u a t e d 7

n e a r l y a t sea l e v e l - Sarahha i e t a l . (1955) have

shown t h a t t h e phase of t h e d i i i r n a l component of meaon

i n t e n s i t y dec reased w l ^ a l t i t u d e , keep ing l a t i t u d e

c o n s t a n t . Our r e s u l t s bea r t h i s o u t f o r meaon a s

w e l l a s n e u t r o n i n t e n s i t y , f h i s means t h a t t h e phase

f o r t h e s t a t i o n s tidiich would be s i t u a t e d a t t h e same

l a t i t u d e a s Oizlmarg and Malcerere but a t s e a l e v e l

would be someidxat l a t e r t h a n «ha t h a s been sôwn i n

S a b l e s 15 and 16. Hence ou r conc lu s ions r e g a r d i n g

t h e l a t i t u d e dependence of phase , w i l l no t be a f f e c t e d

by t h e a l t i t u d e s of Gulmarg and ilakêrere.

f rom f a b l e s 15 and 16 and f i g u r e s 25 and 26, i t

a p p e a r s t h a t t h e phase of t h e d i u r n a l component of

meson i n t e n s i t y a s we l l as t h a t of n e u t r o n i n t e n s i t y

d e c r e a s e s a s l a t i t u d e i n c r e a s e s i n the n o r t h e r n

7 . Y. S a r a b h a i , U.D. Desai and D.Vehkatesan, P h y s . , E e v . , 1940 ( 1 9 5 5 ) .

?7

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?9

l iemisphere . One does no t f i n d t M a r e s i a t i n t h e

s o u t h e r n hemisphere .

I t i s 3eea from Table 1? and 18 aud Fit^. 2?

and 28 t h a t t h e t r e n d of l a t i t u d a dependence of t h e

phase of t h e d i u r n a l component of meaonaa wel l n e u t r o n

i n t e n s i t y i s no t e f f e c t e d by magnet ic a c t i v i t y i n t h e

n o r t h e r n hemisphere .

I n the ease of s e m i - d i u r n a l v a r i a t i o n tne phase

of meson as we l l a s n e u t r o n i n t e n s i t y does not show any

s y s t e m a t i c v a r i a t i o n ( d e c r e a s e o r i n c r e a s e ) wi th

l a t i t u d e i n ho th the h e m i - s p h e r e s . But on m a g n e t i c a l l y

q u i e t days the phase f o r both meson and n e u t r o n

i n t e n s i t i e s d e c r e a s e s wi th l a t i t u d e i n t h e n o r t h e r n

hemisphere only(P^^^'^)

4 . 3 ^ T I T U M DEFBtlDgSOB OF THE PHASE

To exaiaiE^ t h e a l t i t u d e dependence of t h e

phase of t h e d i u r n a l and s e m i - d i u r n a l components of

cosmic-ray i n t e n s i t y , we ana lysed t h e d a t a of t hose

s t a t i o n s livhich a re s i t u a t e d n e a r l y a t t h e same, l a t i t u d e

b u t a t d i f f e r e n t i a l t i t u d e s . Among t h e I . G . Y . s t a t i o n s ,

we s e l e c t e d s i x which s a t i s f y t h e above c o n d i t i o n s .

I n t h i s l i s t , 5 groups of two s t a t i o n s f o r a p a r t i c u l a r

. Diififrbec/ Da^s 0vtet Dt^s

2o/t K

U 0 57N T^/v (fsV

fij-.Zl L ^ T/raos —^

L^T/TL'DF DFPff^OBr\/C£ OF THF PN/9SF fij-.Zl O^T^F D/URr\//Jl COAfPO/^F^T CJF MFSOA/ INTFNSI7Y /V T^F A^OfiTHEfiN HFM/SP/^F^£.

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Q a O O O o t r v o o i e \ o « f i K N o v o <D \ o H (T \ O o • • • • • • • •

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Q ^ 4 3 S rt

o O

O - H KX O t<^ c - KN KN y x o t - KN 0 0 CM i l - CM v o

® o • • • • • • • • o H O o r - l f -4

05 H +> ea H H

II • p • O t - t - i r \ ON O o o « rt a> ta • • • • * • • •

^ « < 5 - 0

o O CM CFS t A H v o J H rt V l o < 5 - 0

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o o H 0 0 t - KV • • • • • • • •

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X

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a-H X 0 0 t- lf\ H K\ t-9 aS

O H

• •

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o <0 d a •H iH •o » U o n o OS <o « o » CJ ra o »

<& XI a) 0 Q} a CO o o a t£S XI

8 i Q - q d s f o r e H Q i e n d e T i n s H njaq^nog

118

»

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e> d> 0 0 lO

o 5 KN tn KS CO o o K> ti •H > • • • • • • •

CO CO o o H l^-ri 04» o d d O o o OH o d P) o tJ s-e M o. (D O o S o JQ O 0) o S o e- r- o s

O <0 o CJ « s iH ITV m o o 01 •p a # • • • • • m tti a o a t> o o o l<\ r-J K\ 1-1 tti

ra+a o aJ •a •

m o o r- V0 O (A <Tt g o a; • • • • • • » H ^ > CO CO t-4 cn U\ to lA OtJ 51 CJ c CO r4 H i-t T-« xf eye

0 -H CO •

i a d SQ 3 o* -H O Vi ^ +» tJ a a ^ d f 05 o ® tJ d © <T> if\ KN o\ m o ® o XI * • • • • • •

<D ® o. lO vo a H tH OS g d a <M Si Q 4»

H fli o CO <»-» m

• « EH O . 13 « t«Q a ce -P e ^ 03 m CQ

{3 >» t«Q a ce -P o o o O o o O S Ti KA o o- CM \o JO o 03 lf\ HI fj ffl 9 a o rt X) 9

-H-H « 4 • d «D H 9 la

a> o n M d o d » as U 1 •

d aj+» •H H o •s U CD o ^ pS o 3) a> • n n AO) 0} a d +» ^ U a 4» Jo +» ^ d <D ctl <B W , o o S as a

•©jands TmeH . d N ajtatide-praeH a* o a -p trjaii!j.Tiog

l a t i t u d e are found and t h e i r d a t a a re shown i n

l a b l e e V^ and 20. I t i s f o r the same

- l a t i t u d e , tiie phuses of the diurneil and t h o s e of

the e e a i - d i a r n a l cocponents of t he d a i l y v a r i a t i o n

- a t h i ^ e r a l t i t u d e s . Th i s i s t r u e

bo th f o r meson S^d n e u t r o n phase s .

4 .4 B i s c u s s i o a

The f a c t t h a t t h e ampl i tude of t h e d i u r n a l

v a r i a t i o n i s very small on t h e p o l a r l a t i t u a e s

s u g g e s t s t h a t t h e v a r i a t i o n i s not caused by a n i s o t r o p y

of j j r i m ^ y o o s a i c - r a y s over t h e e n t i r e energy r a n g e ,

Hossrever, t h e r e appears t o be a c e r t a i n t h r e s h o l d i n

eTnar^ ^spectrum below which t h e r e i s no c o n t r i b u t i o n /

t o d i i i r j i a l v a r i a t i o n . Table 21 shows t h a t t he ampl i -

t^de'^-^f the d i u r n a l and aemi -d iu rna l components of

•%he d a i l y v a r i a t i o n a re l a r g « r i n t h e caee of n e u t r o n

I n t e a j s i t y t h a n f o r meson i n t e » W t y at ©( jua tor ia l aa

wel l as p o l a r l a t i t u d e s .

At t h e e c i u a t o r i a ^ l ^ t t t e i d e s (2°3) and t h e

p o X a r . 8 3 ® H ) l a t i t u d e s , ^ t h e r a t i o between

thf^amplitudea of the d i u r n a l component of n e u t r o n

and ig^son i n t e n s i t y , i a of t he o r d e r of 2.50 snd 1 . 7 7

r e s p e c t i v e l y . For tho rfemi~diarnal component of t h e

51 0

0*H tt n ^ ©

2 O-H

o o

m §• o

n m (D

•O ^ I ® •H ^

41> (0 O fJ

fl a H.ffl-P

04a

0<N

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l l

I t I

^ • CS • _ Q41 JCj H 6

09 S] o

^ ^ B 1 I d o 9 d • M-H O ^ o o t) o 14 vt • a « Q 5 ® H a p f^ JC{ a o ® Oi4* P Oi

I • S i ^ A S t ; n O

^ ^ « -H H O P

+> o o t>

4» B

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o C2)

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vo

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00

— 5 -vO 01 CM CM

H

r-CM

0 vo 0

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CM o>

o vo • tr> CM

o

ri CM

w • § ^ o

P I O O P I

H O

m

e-o

<T> CM

<D "ti-

er* CO • •

ov NO • •

vo t*-H H

cr% 00 • •

t - o H

T5—ap-ir> vo CM CM

T5 ZT" 00 CM •-4 VO H H

o t -VO CM g?

K\ H eo o CM H CM

O in o o O H tn K\ R

o o CM O • •

00 cr>

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i a ta C9 •H 0)

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s

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t> to <D «

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ffl

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05 ^ pki ffl '

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o o «

O O H B) $3 ai <D o ® ra ^

j j 03 aJ >H

8 4 9 g I I S S ^ a . ® ca -H o 4 ^ OJ (D <t3 O -H I P Ot-^ -H f j ® ^ ^ i 2 St Td SSI « KJ o « -H o O q

h a I « O 5J Q <

(D <£> 'tJ <N ® a H =N O OS ® (O

— j

o ts s o a J pst a 0) s a 4» O ai-Pig q ff, ^ U I o a ••H H 0+» p o "o o a 0] (B (t (B rH $:J fM rt O)

^ CJ m U 0

H - H - t a 9 O w s

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(D

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H « r4

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H CO H

o o CTi VO trv t> CM CM

VO c-" VO CM

o ' o CM O GO ON

9 S +» P. (S

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m 09 •H (D

tr\

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CM • iH iH

cr> cr> CM H

O O r-f cy» H fH

t< 0 5 CM CM

H O

o o o o ITS o H • • o lf\ CM H ff\ K\ <y» as

o o 00 c -m in

• 4» S3 U I o, fH

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a} I -p c

1 '

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d 6J -C! H

•H - P

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CD - H

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® •HH +3 t j O, d ® t j ® g 0) Q

o o a ^ "H (D U O-P o 12 2 ** d pj o

CVJ «

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tJ

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o VO H l f \ H O

• • • • CM H CM CM

OT O O o

CM o KN t - <0

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86

d a i l y v a r i a t i o n , t h e r a t i o Eg a t e q u a t o r i a l and t h e

p o l a r l a t i t u d e s i s about 4 .5 and 4 .0 r e s p e c t i v e l y .

Th i s shov./s t h a t t he E a t i o i s l a r g e r f o r t h e

s e m i - d i u r n j ^ component t h a n f o r the d iu rn t . ! component

of t he d a i l y v a r i a t i o n .

CHAP!E£& V.

SIUDY Qg THE DAILY VARlAlIOlf Qi COSMIC &AY IHIENSI!CI OH MASBi glCALLY mSTURBED AHD QUIET 13AYS.AI mg^'EREHI

LATITUDES I S BOTH THE HSal S P H l ^ S .

The s tudy of t h e ampl i tude and phase of t h e

d a i l y v a r i a t i o n a t d i f f e r e n t l a t i t u d e s i n bo th

t h e h e m i - g p h e r e s p a r t i c l u a r l y on m a g n e t i c a l l y dis-fco/^beci

tiiPl bated and q u i e t days pro v i a e s an i m p o r t a n t t o o l t o

examine t h e energy spect rum of t h e pr imary a n i s o t r o p y

r e s p o n s i b l e f o r t h e d a i l y v a r i a t i o n . From t h i s s t udy

we can l e a r n about t h e v a r i o u s i n f l u e n c e s on c o s m i c - r a y

i n t e n s i t y a r i s i n g from t h e e l e c t r o m a g n e t i c c o n d i t i o n s

of i n t e r p l a n e t a r y space and of t h e sun . fiowever, such

a s tudy i s d i f f i c u l t because of l a c k of cosmic r a y 1 2

da ta} a l t h o u g h some r e s e a r c h g roups ' have a t t e m p t e d

i t e a r l i e r .

Recen t ly f t h e I .Cr .Y. , c o s m i c - r a y meson

t e l e s c o p e s and n e u t r o n m o n i t o r s a l l o v e r t h e wor ld

have p r o v i d e d d a t a which may De u s e f u l l y a n a l y z e d .

We a n a l y s e d t h e p r e s s u r e c o r r e c t e d d a t a of n e u t r o n

and meson i n t e n s i t y f o r t h e I . G . Y . s t a t i o n s g i v e n

i n T a b l e 12 .

1 . H . E l l i o t , P r o g r e s s i n Cosmic-ray p h y s i c s , i , 4 5 5 ( 1 9 5 2 ) 2 . V . S a r a b h a i , and®.W.Herurkar, Annual , Hev. N u c l e a r ,

' S c i . , 6 , 1 , U 9 5 6 ) .

88

I n o r d e r to s tudy t h e n a t u r e of t h e d a i l y

VcaTiation of t h e co smic - r e^ meson and t h e n e u t r o n

i n t e n s i t y on d i s t u r b e d ana q u i e t d a y s , we have

averaged both meson and n e u t r o n i n t e n s i t y d a t a o f

a l l t h e s e tv/o t y p e s of jdays s e p a r a t e l y f o r t h e p e r i o d

J a n . t o Dec. 1958. Then u s i n g t h e 12 h i h o u r l y v a l u e s

f o r t h e two d i f f e r e n t t y p e s o ^ d a y s , f i r s t and second

harmonic components have been c a l c u l a t e d . I n t h i s

way meson and n e u t r o n d a t a have been a n a l y s e d and t h e

r e s u l t s a r e g i v e n i n T a b l e s 22 to 25.

5 . 1 DIUaHAL VAaiAgios OH MAGHEIICALL^ msTURBED AHS QDIEg DAYa.

Prom Table 22, i t i s d e a r t h a t a t p o l a r

l a t i t u d e s ( >s =85°H, X = 75®S) t h e d i u r n a l a m p l i t u d e

of t h e meson i n t e n s i t y i s a lmost t h e same on

m a g n e t i c a l l y d i s t u r b e d and q.uiet days . At o t h e r

s t a t i o n s i n t h e n o r t h e r n h e m i s p h e r e , Ot tawa (57°N)

C h u r c h i l l (70®H), i t i s found l a r g e r on m a g n e t i c a l l y

q u i e t days t h a n on d i s t u r b e d days'^.* The same was

o b s e r v e d by Sekido , e t a l . (1950)^ a t Nagoyo (>v«25®K).

However, Hogg (1949)* , i n t h e case of t h e i o n i s a t i o n

5 . y . S a k i d o , M.Kodama, and T . I a g i , R e p t . I o n o s p h e r e , A e s . , J a p a n , i , 207 (1950) .

4 . A.ft .flogfa., MemSiirs of t h e common w e a l t h o b s e r v a t o r y , Ho. 10 ( 1 9 4 9 ) .

t The a u t h o r a t Gulmarg ( X « 2 4 . 7 H) a l s o oDserved t h a t t h e a m p l i t u a e i s l a r g e r on q u i e t days t h a n on t h e d i s t u r b e d d a y s .

126

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%

ITN o r- UN cr> o 00 aj-j • • • • • • • • o S'-i o o CM <Tv KS irt H VO S'-i H r-4 iH H H i-i o ^ o • VO VO o CM VO IfN o H c5 H H r-l H H ^ o O O O O O O O O d flrf •o • • • • • • • tzin O O. o o O o o. o •H 5' 5' 1' n <j> H CM VO m 1' A H H CM CM CM • O • O • o • O • O • O • O • o a • o U o 1-4 00 t- K\ • • • • • • • « « o m J <0 ey CM CM J <0 H CM CM CM o-o •

s tJ *£> VO o K\ CM VO ITS O s tJ -a H H c5 1-4 H H r-l to O O O o O O O O o •p • • « • • • • « •H O o. o o o O o o CO 4> H 2" A' 8' U 09 g H 8' lf\ o H tr\ H « C\l • CM • CM • CM • • •

CM • O o O o o O O O • > • O cfiu b * i n HN U\ in t- C 3 t4 r-l H H H r4 H H

• • 1 • • • • • CO o o O 1 O O O O O ® 4) P« ^ Q •H o o +»

* m tzs to £0 09 to CO a ed o o o O O o o a o c- CM VD H KN o <D m H VO o <D cS

• • fl H • * 0) o 0 H 00 •H T4 •r4 • h • •H JC3 oi Q> {2 d a oJ rH o g ^ 3 d o -P O H 0) 0 • o" e> M (S 0 1 4» +» § s « o «J S m o o w a a

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o 43 o. o . o. o o o o «J +»

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• •

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a> ftS +»

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ir\ 00

o CVJ tA O 00 K\ • • • o o ^ r4

cr\ CT» in cr> KN o o O o H CM CM o o o o o O O • • • • • « •

o . o . o o . o . o o A' 4 ' CM CM CT\ 00 CM o CM H O o

• • • • • » • O o o o O o o

CJ si t - o o O o J • m -t cn oo H if\ m CliflJ « « • • • • o ^ OS O O o H t<-\ H O "Xi Xi i fM ^ f Xi i fM ^ -H ® O a ^ as cn lA m S o o O CM S d m o o o O o O O n • • • • • • •

0 o . o . o o . o o o . +1 +1 +1 j-y M •i-t ri ri •H § t i m o o H VO § o CM o\ 00 o Oi H CM CM o H o {| » • • • • # • m o O o o o o o

S • TJ 12! ts iz; 02 OJ O o o o O o o KN o CM VO K\ 00 lA H o-^ (D cS

• • H • 0) r-t v> d •H • ^ • o Jj OS a> a

fHI M a h w O 4a. O ^ <a o a n OS 03 •p « » (D a +» CO « (d

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• • « • • • • • 00 O o CM i r \

v o v o o CM vo t n o H H CM «— r » r -O O o o o O o o

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KN 00 o t>- (Ti IfN CM O ; o CM O O t— o O

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\ o K \ CM vo irv o i H

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o . o o o o o o o + 1 + +1 + 1 +! -i-l

H o o vo CM vo 00 00

o i H CM o r— a o o 'a • • # • • • •

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o t - CM ^ r v 00 i r . VO

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© X H a> !» •H -H •H • • • ^ Si OS © S a H O ? u CO o O cts 9 • o* 0) GO S! •p o o ? O ^ +> B5 (D (0 d

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• a 0 0 0 0 - H SJ • • • «

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m d & ^ f - « + 1

t r » ^ P S3 a ot CO CM

0 € # # • +>

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• • t o

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t * -• i n • • ffl ^ C J if\ e - m

d ® (k H O o "CJ

(k o sJ ®

p j ® 4 9 0 a - H d p j ® 4 9 0 a - H d

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f H a

0 r H P< S!

Co CO Q) 4

CNJ CM H 4 • •

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r » • n

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© C J S a

C J - t J CVJ CM 4 * •r< 0 r - l ^ •

a 1 W5 d 0 0 0 0

0 <8 0 t — 0 0 c - CO « e-ri-H i n U N I T l

§ ® as + » © C!3 flo rt fl a> 0 rt fl a> 0 0 rt PI • ^ 3 0 OS a 3 •

f M 0 ^ • m

f M 0 a A a a a) +=» H a - p r - l •f

0 a + » 0 a

• q . H S T I O d W O 0 • ^ . t t e m o d M O O

T t o e e H a o a ! | . t t 9 | |

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CJliamber d a t a and Wada (1950)^ l a t h e case of meson

i n t e n s i t y d a t a obse rved t h a t t h e ampl i tude h a s n e a r l y

t h e same v a l u e on d i s t u r b e d as we l l as q u i e t days .

I n t h e s o u t h e r n hemisphere a t Makerere (2°)

Lae (16®), Hermanus (33°) and Maquarie (61°) t h e

ampl i tude i s l a r g e r on m a g n e t i c a l l y -quie-t days t h a n

on q u i e t days .

I n t h e case of the n e u t r o n i n t e n s i t y , t h e

ampl i tude i s l a r g e r on m a g n e t i c a l l y q u i e t days than

on d i s t u r b e d days a t a l l the d i f f e r e n t l a t i t u d e s

i n the s o u t h e r n hemisphere . But , i n t h e n o r t h e r n

hemisphere , a t Ottawa (57°) > t h e d i u r n a l eaaplitude

i s l a r g e r on q u i e t days th£ui on t h e d i s t u r b e d days;

Tshile a t o t h e r h i ^ e r p o l a r l a t i t u d e s , ©hurch i l l

(70®) and Reso lu t e (83°) the eaaplitude i s l a r g e r on

d i s t u r b e d days tJaan on q u i e t days . She d a t a i s

summ^zdzed i n Sab le 26.

5 . 2 IHE PHASE OF THS BIPESAL VAHlATIOg 6H DIS5UEBEB AHD QUIBT PAYS.

The phase s of t h e f i r s t harmonic component

of meson and n e u t r o n i n t e n s i t y a re g iven i n l a b l e s 22 & 23*

5 . M.Wada, Read a t t h e seventh General Meet ing of Soc. !Eerr. Mag. <1: £ l e c t . J a p a n , 1930.

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9

From Table 231 i t i s c l e a r t h a t t he phase f o r

n e u t r o n s i s s m a l l e r on d i s t u r b e d days t h a n on q u i e t days

a t d i f f e r e n t l a t i t u d e s i n t h e n o r t h e r n hemisphere , *ftiile

a t d i f f e r e n t l a t i t u d e s i n the s o u t h e r n hemisphere t h e r e

i s no s y s t e m a t i c r e l a t i o n .

i n t h e case of t h e meson i n t e n s i t y , i n t h e

n o r t h e r n hemisphere , a t l a t i t u d e s 85® and 70° the

phase i s s m a l l e r on d i s t u r b e d days t h a n on q u i e t days ,

excep t a t Ot tawa { m 57^U), vdaere i t i s t h e same on

both t y p e s of days . I n t h e s o u t h e r n hemisphere , a t

a l l t h e d i f f e r e n t l a t i t u d e s t h e phase i s e a r l i e r on

q u i e t days t h a n on d i s t u r b e d days . Thus t h e n a t u r e

of the phase on d i s t u r b e d days and q u i e t days i n t h e

n o r t h e m hemisphere i s o p p o s i t e of what i t i s i n t h e

s o u t h e r n hemisphere .

The v a r i a t i o n of t h e phase of meson i n t e n s i t y

i n t h e n o r t h e r n hemisphere i s s i m i l a r to was a l r e a d y

r e p o r t e d by Hogg (1949) ^f Wada (1950)^ and Selcido e t a l .

( 1950 )^ .

5 . 3 Sm~IP0&5AL CQMPOHEHT OK PI STUBBED AHI> QUIET BI^S.

I n t h e case of the semi>d iu rna l components of

meson and n e u t r o n i n t e n s i t y ampl i tudes and phases a r e

shown i n T a b l e s 24, 25. I t i s c l e a r from t h e s e t a o l e s

t h a t t h e ampl i tudes are q u i t e s i g n i f i c a n t a t v a r i o u s

l a t i t u d e s i n both t h e hemispheres .

At a l l t h e n o r t h e r n and sou the rn l a t i t u d e s

examined h e r e , t h e s e m i - d i u r n a l ampl i tude i s l a r g e r on

a

9?

m a g n e t i c a l l y d i s t u r b e d days t h a n on <iuiet days ,

excep t a t Mawson ( 7 3 ° 3 ) .

The semi-diurnal ampl i tude a t d i f f e r e n t l a t i t u d e s

i n Doth t h e hemispheres a l s o ahoAs t h a t i t i s l a r g e r

on m a g n e t i c a l l y d i s t u r b e d days than on q u i e t days,

exoept a t Hermanus ( X ® 54^3) where t h e change i s

o p p o s i t e i n n a t u r e , ih, iaA>:b*du

Sab le 54 shows t h a t a t a l l t h e phase of t h e A

n e u t r o n i n t e n s i t y y A - a t i t u d o c i s e a r l i « r on d i s t u r b e d

days t h a n on q u i e t days , excep t a t Lae ( X = 16®3)

where the change i s o p p o s i t e but s l i ^ t . The phase of

t h e semi-di^i rnal component of » e s o n i n t e n s i t y does n o t

show any s y s t e m a t i c and c o n s t a n t behaviour a t a i f f e r e n t

l a t i t u d e s a s i s shown i n t h e case of t h e n e u t r o n s .

Here* t h e phase i s a l s o e a r l i e r on d i s t u r b e d days

t h a n on q u i e t days excep t a t C h u r c h i l l (70*^5) and

Macquarie ( 6 l ° S ) \ ^ e r e i t i s e a r l i e r on q u i e t days ,

5 . 4 ALMUJ3B PJSP-ENBgjJ B OF OM HISTURBBB i^D QUIBI DA^S.

^ o m Hable i s n o t i c e d t h a t i n t h e

caae of both meson and n e u t r o n i n t e n s i t y t h e phase

o i t h e d i u r n a l v a r i a t i o n i s e a r l i e r a t h i g h e r

a l t i t u d e s f o r t h e same l a t i t u d e s . This f a c t i s

a l s o found on m a g n e t i c a l l y d i s t u r b e d £uid q u i e t days .

3-8

2!ki8 I s i n agreement with our r e s u l t s i n Chapter IV.

!fhe phase o f the a e a i - d l u r n a l v a r i a t i a n of

n e u t r o n i n t e n s i t y i s a l so e a r l i e r a t h i ^ a l t i t u d e s

f o r t h e ssaae l a t i t u d e s on both t y p e s of days . But

f o r meson i n t e n s i t y t h e s e m i - d i u r n a l phase shows t h i s

n a t u r e on ly on m a g n e t i c a l l y q u i e t days .

5 . 5 CQMPAEAgiyi; srJBY OF TUB EATURE QF DAILY YAElAflQH Qif CQ^IC £A^ IMI^fiSIIY AT DMFmMSMf IH H3IH TOE

The n a t u r e of t h e average d a i l y v a r i a t i o n

of t h e meson and n e u t r o n i n t e n s i t i e s a re examined

on magnetL c a l l y d i s t u r b e d and q u i e t days s e p a r a t e l y

a t d i^ f fe ren t l a t i t u d e s on bo th s i d e s of t h e e q u a t o r .

The cu rves r e p r e s e n t i n g t h i s average d a i l y v a r i a t i o n

a re g iven i n f i g . 29 to 32,

5 . 5 ( a ) DAILY YARIAflOa OH BISggRSSB BATS

!Ehe c u r v e s i n f i g . 29, show t h a t the

average d a i l y v a r i a t i o n of t h e n e u t r o n i n t e n s i t y , on

m a g n e t i c a l l y d i s t u r b e d ds^st a t d i f f e r e n t l a t i t u d e s

i n both t h e hemispheresf h a s two maxima and two minima

A and B. !I!he minimum A p r e c e d e s the midnight ma:£iaum

by about an hour a t a l l the l a t i t u d e s except Makerer*

and La.e (16®S) ^ e r e i t p r e c e d e s by about two hours .

S.

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99

I n t h e n o r t h e r n hemisphere t h e d a i l y v a r i a t i o n ,

of n e u t r o n i n t e n s i t y i s of s i m i l a r n a t u r e on a l l t h e

l a t i t u d e s examined h e r e , hav ing two maxima (one a t

m i d n i ^ t and o t h e r between 1800-2000 h r s ) and two

minima A and B. The second broad minimum fi o c c u r s a t

about 1100 h r s . U.T. (between 0900-1500 h r s . ) .

I n t h e sou^ the rn hemispheres t h e n a t u r e of t h i s

d a i l y v a r i a t i o n does not show t h e same f e a t u r e a s

obse rved i n t h e n o r t h e r n hemisphere . Here the second

maximum B o c c u r s a t about 1500 h r s . U.S. (be tween

1100-1500 h r s . ) .

Another p o i n t which i s appa ren t from t h e cu rves

i n f i g . 29f i s t h a t the gene ra l n a t u r e of the d a i l y

v a r i a t i o n of n e u t r o n i n t e n s i t y i n t h e n o r t h e r n hemisphere

i s o p p o s i t e to t h a t of the d a i l y v a r i a t i o n i n t h e

s o u t h e r n hemisphe res .

Prom t h e curves i n P i g . 50, which r e p r e s e n t

t h e d a i l y v a r i a t i o n of meson i n t e n s i t y on d i f f e r e n t *

l a t i t u d e s i n both the hemispheres , t he f o l l o w i n g p o i n t s

can be drawn s -

( i ) On a l l t h e l a t i t u d e s t h e d a i l y v a r i a t i o n of

meson i n t e n s i t y shows one maximiuB a t m i d n i ^ t and i s

p receded by a minimm A, which i s sharp i n t h e x i s r the rn

TMf/Jtfft^e omv VMtMTlOM Of Mesa^ '' COMfW^f/r or COSmC'Mftr t^TCMStfKOM

M/iAM I'cmiY otSTtMtilo Dt^ys.^r Curr/M/A/T l^TfTt/OfS.

100

hemisphere axid sha l low i n t h e s o u t h e r n h e m i s p h e r e .

(2) lEhe second b road maximum ( i n t h e a f t e r n o o n )

i n t h e n o r t h e r n hemisphere s l i d e s t o e a r l i e r h o u r s

a s t h e e q u a t o r i s approached .

(5 ) The second minimum B i n t h e n o r t h e r n h e m i s -

phe re a l s o s l i d e s s l i g h t l y to e a r l i e r h o u r s a s t h e

e q u a t o r i s approached and i t i s s h a l l o w i n h i ^

l a t i t u d e s .

( 4 ) But f o r Hermanus { X » 54*^3), t h e second

maximum and minimum a r e h a r d l y n o t i c e d i n t h e s o u t h e r n

l a t i t u d e s .

(5 ) I n t h e n o r t h e r n hemisphere a t a l l t h e l a t i t u d e s

the d a i l y v a r i a t i o n of meson i n t e n s i t y a l s o snows a

s i m i l a r i t y i n n a t u r e , h u t t h i s i s n o t o b s e r v e d on t h e

l a t i t u d e s i n t h e s o u t h e r n h e m i s p h e r e .

5 . 5 ( h } DAILY YAsHASlO^ OS UUIEI PAX^

The f o l l o w i n g ^ p o i n t s may be drawn f rom t h e

n a t u r e of the d a i l y v a r i a t i o n of meson and n e u t r o n

components , on que t days , a t d i f f e r e n t l a t i t u d e s

i n b o t h t h e h e m i s p h e r e s .

(1) IThe c u r v e s i n P i g , 31 , show t h a t t h e d a i l y

v a r i a t i o n s of meson component g e n e r a l l y have on ly one

maximum and one minimum.

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10

(2) I n t h e n o r t h e r n hemispheres t h e maximum i n

the even ing s h i f t s to e a r l i e r hoiira a s t h e e q u a t o r i s

approached and i t becomes sha rpe r i n t h e r e g i o n of

57® l a t i t u d e .

(3) I n t h e s o u t h e r n hemispheres t h e maximum and

minimxam become s h a r p e r a s v/e move away from t h e

e q u a t o r , f h e t ime of t h e s e maxima and minima a l so

changes back gind f o r t h a s t h e p o l e s a re approached.

(4) The d a i l y v a r i a t i o n of meson i n t e n s i t y , on

q u i e t days , shows a s i m i l a r i t y i n n a t u r e , on d i f f e r e n t

l a t i t u a e s i n t h e n o r t h e r n hemisphere . But i t i s not

obse rved i n t h e s o u t h e r n hemisphere where t h e d a i l y

v a r i a t i o n i s d i f f e r e n t a t d i f f e r e n t l a t i t u d e s .

(5) The cu rves i n F ig , 52, show t h a t t h e d a i l y

v a r i a t i o n s of n e u t r o n component a l s o have one"maximum

and one minimxim on a l l t h e l a t i t u d e s i n bo th t h e hemis -

p h e r e s except a t t h e e q u a t o r .

(6 ) I n t h e iu>rthern hemisphere the maximum remains

a t 23 h r s . upto l a t i t u a e 58® and t h e n s h i f t s t o

e a r l i e r h o u r s a s t h e equa to r i s approached. The

minimum a l so s h i f t s to e a r l i e r hou r s and becomes

s h a r p e r as equa to r i s approached.

(7) I n t h e sou the rn hemisphere t h e maximum s h i f t s

- • i

fftiOCUTT (Si'M)

AK/'TV AMC < C V V

s/n/rpohJ r ' a/ ^ost^fC-^^Y /A'/Z/VJ//^J/V -V/ V R / V 4FOFET D//yi, ''/r Of/ f / f f f Af 7 l/7r/Ti/ors.

102

t o e a r l i e r h o u r s very much l i k e the s h i f t of t h e

miniiBUBi i n t h e n o r t h e r n hemisphe res .

(8) Proa t h e ciirves i n P i g . 31 & 32, one may say %

t h a t t h e d a i l y v a r i a t i o n of meson and n e u t r o n i n t e n -

s i t i e s show a s i m i l a r i t y i n n a t u r e amongst t h e

d i f f e r e n t l a t i t u d e s i n t h e n o r t h e r n hemisphere , b u t

i t does not show t h i s s i m i l a r i t y i n t h e s o u t h e r n

hemisphere .

5 , 6 D i scuss ion Aim Qg &ESULTS.

(1) f h e ampl i tude of t h e d i u r n a l component of

t he d a i l y v a r i a t i o n of t h e cosmic-ray i n t e n s i t y h a s

f r e q u e n t l y been c o n s i d e r e d an index of the degree

of a n i s o t r o p y of pr imary r a d i a t i o n .

f a b l e 28 shows t h a t the d i u r n a l ampl i tude

of th® d a i l y v a r i a t i o n observed wi th t h e n e u t r o n

moni to r i s g r e a t e r t h a n t h a t obse rved by the meson

moni to r a t low and h i g h ' l a t i t u d e s i n both t h e hemi-

s p h e r e s . (Thus i t shows t h a t t h e a n i s o t r o p y i s g r e a t e r

i n the spectrrim i n t h e mean energy r ange of about

7Bev (which i s measured by a n e u t r o n moni to r a t

middle l a t i t a d e s ) t h a n i n the spectrum with a mean

energy of about 40 Bev. (which would be measured a t

103

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104

a s i m i l a r s t a t i o n with a meson i n t e n s i t y m o n i t o r ) .

l a b l e 28 a l so shows t h a t t h e i i a t i o ^ i s l a r g e r a t

e q u a t o r i a l l a t i t u d e s a s compared to t h e h i ^ e r

l a t i t u d e s *

(2) A l f v e n ' (1950)^'"^ e x p r e s s e d t h e h i g h l y

impor t an t concept t h a t c e r t a i n a n i s o t r o p y of cosmic-

r a y s may be due to the a c c e l e r a t i o n and r e t a r d a t i o n

of p a r t i c l e s i n t h e f i e l d s of t h e c o r p u s c u l a r s t r eams

e m i t t e d by t h e sun.

Q

E l l i o t and Dolbear (1951) have sugges t ed

t h a t t he s o l a r d a l l y v a r i a t i o n i s due t o t h e a n i s o t r o p y of

t h e pr imary r a d i a t i o n c r e a t e d by t h e i n f l u e n c e of t h e

c o r p u s c u l a r s t r e e m s e m i t t e d by t h e sun, on pr imary

r a d i a t i o n .

According t o E l l i o t and Dolbear (1951)^ ^ o

have vsorked ou t some conse(iuencea of the t h e o r y , i t

should l e a d to a dec rease i n i n t e n s i t y i n t h e l a t e

morning aJid an i n c r e a s e s h o r t l y a f t e r t h e noon.

Th i s c o n c l u s i o n i s i n q u a l i t a t i v e agreement wi th t h e

e x p e r i m e n t a l r e s u l t s a n a l y s e d h e r e f o r the n o r t h e r n

l a t i t u d e s (shown i n . The d a i l y v a x ' i a t i o n

obse rved on m a g n e t i c a l l y d i s t u r b e d days i s i n very

c l o s e agreement with t h e above i n t e r p r e t i a t i o n . doYi-6 . H .Al fven , Cosmical E l e c t r o d y n e m i c s ( 0 x f o r d ) C h . T I , ( l 9 5 0 ) . 7 . H .Al fven , Phys .Eev . 1752 ( 1 9 4 9 ) . 8 . H . E l l i o t , and D . W . N . ^ l b e a r , J . A t m o s . T e r r . P h y s . i , 2 0 5

( 1 9 5 1 ) .

105

e v o r , oa r a n a l y s i s Tor t h e a o a t n e r n i iemisphere

does not bear t h i s out»

j a i l o t and Dolbear (1951)^ a l s o i n d i c a t e d

t h a t t h e ampl i tude of t h e d a i l y v a r i a t i o n woiild Do

l a r g e r on m a g n e t i c a l l y d i s t u r b e d days . They showed

i t t o be so from t h e i r r e s u l t s f o r a minimum s o l a r

a c t i v i t y p e r i o d . Th i s h a s been found t o be g e n e r a l l y

t r u e f o r oa r d a t a , v^nich i s f o r the p e r i o d of maximum

s o l a r a c t i v i t y . Bat t he d i f f e r e n c e between t h e a a i l y

v a r i a t i o n on d i s t u r b e d and q u i e t days i s l a r g e r d u r i n g

t h e p e r i o d of minimum s o l a r a c t i v i t y .

I t i s s i g n i f i c a n t t o p o i n t ou t t h a t a t some

of the l a t l t a d e s the v a r i a t i o n appea r s t o be l a r g e

on q u i e t days t h a n on d i s t u r b e d days . S h i s anom^y

caniiOt be e x p l a i n e d by t h e above h y p o t h e s i s a s

such , f h e need f o r a more comprehensive t h e o r y of

c o a a i c ray a n i s o t r o p y i s h i g h l i ^ t e d by t h e s e r e s u l t s .

lOS

CaAI>!EE& — YI.

THE IKFLUEHOS OF S&lALL SOLAR FLAfi^S ON TEE ISTEmiTY OF THE HARD CQMfOSJSM? OF

GQSMIG RABIATIOE.

The s tudy of i n c r e a s e s of cosmic-rety

I n t e n s i t y a s s o c i a t e d vidth l a r g e soXar f l a r e s h a s

p rov ided v a l u a b l e i n f o r m a t i o n r e g a r d i n g t h e i n t e r -

p l a n e t a r y megne t ic f i e l d s , p r o p a g a t i o n of charged

p a r t i c l e s from t h e sun to t h e e a r t h and t h e energy

spectrum of s o l a r f l a r e p a r t i c l e s .

Al l t h e f l a r e s which were obse rved i n t h e

p a s t were of h igh impor tance and t h e c o r r e s p o n d i n g

i n c r e a s e of cosmic- rsy i n t e n s i t y was obse rved a t a

number of widely s e p a r a t e d s t a t i o n s . The f i r s t

cosaiic«>ray i n c r e a s e a s s o c i a t e d wi th a s o l a r f l a r e

was obse rved a t a number of widely s e p a r a t e d p l a c e s

on Feb. 28 and March 7 , 1942 by Berry and H e s s ( l 9 4 2 ) ^ , 2

and Lange and Forbush (1942) . O the r s i m i l a r i n c r e a s e s

were observed on J u l y 25, 1946, and Nov. 19, 1949, by

Forbush (1946)^ , D a u v i l l i e r (1949)^ , Forbush, S t inchcoab

1 . E .B .Ber ry , and V,F, Hess , T e r r . Jlagn. A tmos .E lec t . 1 1 , 251, ( 1 9 4 2 ) .

2 . I .Lange and S.E.Forbush» Ter r .Hagn .Atmos .E lec t . 1 2 , 551, ( l j 4 2 ) .

5 . S .E .Forbuah , Phys . f iev . JO, 771 (1946 ) . 4 . A . D a a v i l l i e r , C.fi.Aced. S i r . , P a r i s , 229 .1096(1949) .

1 0 7

fl^i^ Schein (1950)5 , Hose (1950)^ and Adams (ig&O)"^.

The f i f t h cosmic- ray i n c r e a s e a s s o c i a t e d

witJa a very i n t e n s e s o l a r f l a r e was observed on 25rd

Feb. 1956. Th i s was the only case i n which o b s e r v a t i o n s

ex tended from t h e equa to r t o h i g h e r l a t i t u d e s . Th i s

s o l a r f l a r e was of impor tanee 3*, said more proiK>unc6d

i n c r e a s e s of cosmic-ray i n t e n s i t y were r e c o r d e d a t

t h i s t ime t h a n d u r i n g t h e e a r l i e r e v e n t s , i lo rsden

e t a l . (1956)® r e p o r t e d an i n c r e a s e of about 45003&

i n a n e u t r o n moni tor a t X « 57®N. Lambie and E l l i o t

(1956)^ a l s o r e p o r t e d an i n c r e a s e of about 1203t

i n a G-M coun te r a r r a y i n London. I n I n d i a , Sarabhai

e t . a l . (1956)^^ r e p o r t e d an average i n c r e a s e of 5.7?^

a t s t a t i o n s nea r t h e e q u a t o r , and on t h e b a s i s of

Burnberg and Da t tne r*8 c a l c u l a t i o n s , they s u g g e s t e d

t h a t i n c r e a s e s a t t h e s e I n d i a n s t a t i o n s were caused

by s o l a r p r o t o n s i n t h e energy range 50 to 67-5 Bev,

The c h a r a c t e r i s t i c f e a t u r e s of t h e i n c r e a s e s

du r ing t h e s e g r e a t f l a r e s can be summed up a s f o l l o w s ;

World-wide l a r g e i n c r e a s e s i n cosmic-ray i n t e n s i t y

a re very r a r e and a re a s s o c i a t e d with e x c e p t i o n a l l y

i n t e n s e s o l a r f l a r e s . The i n c r e a s e i n i n t e n s i t y p r o c e e d s very r a p i d l y , i n a few m i n u t e s , b u t t h e

5. S .E .gorbuah . T.B.St inchcomb. M.Schein«Phys.&ev.79» ' 501 ( 1 9 5 0 ) .

6 . D.C.Bose, Phys.Rev, 78, 181 ( 1 9 5 0 ) . 7 . H.Adams, P h i l Mag. i i , 505 ( 1 9 5 0 ) . t S e e append ix -2 . 8 . P.I i .Morsden, J . f f . Beery, and P . F e i l d h o u s e , J .Atoms.

T e i x P h y s . , 8 , 278 (1956) . A77 9 . M.Lambie, and H . E l l i o t , J .Atmos, T e r r . P h y 3 . ^ 1 9 5 6 ) 10 .V .Sa rabha i ,S .P .Dagga l ,H .Eazdan , and T . S . G . S ^ t r y

P r o c . I n d i a n , Acad. S c i . 509(1956) .

r a t u r n t o t h e normal l e v e l i s c o n s i d e r a b l y s lower

and t a k e s s e v e r a l liOTars. f h e maxLmuia of cosmic-rs^y

i n t e n s i t y o c c u r s about an hour a f t e r t he maximiua

of t h e v i s u a l e f f e c t . The magnitude of t h e i n c r e a s e

depends on t h e mode of d e t e c t i o n , and on l a t i t u d e ,

l o n g i t u d e and a l t i t u d e . I t i n c r e a s e s with a l t i t u d e

and l a t i t u d e , The e f f e c t i s much l a r g e r on the

n e u t r o n i n t e n s i t y t h a n on the h a r d component.

Eamert (1948)^^ , us ing a few o r b i t s of

c o a a i c - r a y p a r t i c l e s i n t e g r a t e d by Stormer (1954)

showed t h a t t h e d i s t r i b u t i o n of i n c r e a s e of Feb. 28,

1942, «aiich was observed i n i m e r i c a but no t i n

Geriaany, i n d i c a t e d l h a t p o s i t i v e p a r t i c l e s a r r i v e d

from t h e d i r e c t i o n of t h e son. S d i l u t e r (1951)^^

i n t e g r a t e d a few more o r b i t s and ^ o w e d t h a t tiiere

a r e p r e f e r r e d l o c a t i o n s of impac t s of p a r t i d e s on

the e a r t h . Such l o c a t i o n s a r e c a l l e d ^Impact Zones"-

L a t e r P i r r o r (1954)^^ , u s ing t h e o r b i t i n t e g r a t i o n s

of Stormer ( 1 9 5 4 ) ^ ^ D H i ^ t (1950)^? S c h l u t e r (1951)^^

and the r e s u l t s of the model exper iment of Malmfors

1 1 . A . l h m e r t , S . H a t u r f o r s c h . 264 ( 1 9 4 8 ) . 12 . A. S c h l u t e r , Z . H a t u r f o r s c h , 615 ( 1 9 5 1 ) . 13 . J . F i r r o r , p h y s . Eev. lOPf (1954 ) . 14 . C .S tormer , A s t r o p h y s i c s , Horv . , 1 , 1 (1934 ) . 15 . K . S w i ^ t , Ph5S.Rev. 78, 40 (1950 ) .

109

(1945)^^ and Buraberg showed t h a t t h e r e

a r e v a r i o u s Impact zoxies f o r t h e p o s i t i v e p a r t i c l e s

e m i t t e d from t h e &uu* But t h r e e of them s i t u a t e d

a t 0900 h r s . , 0400 h r s , , and 20Q0" h r s . a r e more

i m p o r t a a t t h a n the o t h e r s and the r a t i o , of t h e i n t e n -

s i t i e s i n t h e s e impact ao"nes i s 7 j 5 : 1 r e s p e c t i v e l y .

Obv ious ly , t h e 0900 h r s . , isnpact zom i s t h e most

i m p o r t a n t and i t e x t e n d s from alwut and S

geomagnet ic l e i t i t u d e to 70° geomagnet ic l a t i t u d e s .

She 0400 h r a - zoae s t r e c h e s from about 55° t o 65°N

and B geomagnetic l a t i t u d e and t h e 2000 h r s . ssone,

or t h e background impact zone* e x t e n d s from about

50° to 60°H and S geomegn. l a t i t u d e .

She above a n a l y s i s was done on t h e assumpt ion

t h a t t h e source of pspr t i c le e m i s s i o n i s a po in t o m .

But from t h e v i s u a l o b s e r v a t i o n s we know - ^ a t t h i s

i s n o t t h e ca se , f h e source h a s g o t a f i n i t e s i z e

and i t m a n i f e s t s i t s e l f i n t h e bix>:>adening of t h e

impact zones . I t i s common p r a c t i c e to take t h e

width of t h e zone a s 4 h r s .

From t h e p l o t s of f i r r o r ' s ^ ^ s i s (1954)^^

and knowing t h e geomagnetic l a t i t u d e and l o n g i t u d e .

16 . E.G.Maimfors , Arkiv . Mat. Astron» P y s i k , A52, No.8 (1945 ) .

17 . E.Burnberg» j .Geophys . Res . 272 ( 1 9 5 5 ) .

1 1 r X JL

of t h e p lace* one can e a s i l y f i n d o a t a s t o which

s t a t i o n w i l l toe i n any p a r t i c u l a r zone a t any g i v e n

t i m e . The f o l l o w i n g approximate r e l a t i o n of McNish

(1956)^® i s very coavei i ient t o conve r t from t h e

U n i v e r s a l t ime t o t h e l o c a l t i m e .

15^

^shere A i s t h e geomagnetic l o n g i t u d e of t h e

p o i n t of o b s e r v a t i o n , t deno tes u n i v e r s a l t ime ,

and 9 s t a n d s f o r l o c a l o r geomagnetic t i m e .

6 . 1 GQSMIG~RAY IHCR^ ASii.-AO! GOLEAdG (A«i24.7^S)

5?he e f f e c t of t h e s o l a r f l a r e s of impor tance

1 and 2 on cosmic- ray i n t e n s i t y i s r a t h « r l o c a l i z e d

and only a few r e p o r t s of t h e i r e f f e c t s have appeared

i n l i t e r a t u r e . P e t e r s o n and Winckler (1958)^^ , Of)

Cor r igon ( 1 9 5 8 ) ^ , Winckler a t . a l . ( l 9 5 9 ) have

r e p o r t e d cosmic- ray i n c r e a s e s a s s o c i a t e d wi th smal l

s o l a r f l a r e s . We have a l s o r e c o r d e d an i n c r e a s e i n

18 . A.C. McSish, T e r r . Magn. and Atmos. E l e c t . 4 1 * 57, ( 1956 ) .

1 9 . L . P e t e r s o n , and J . i i . f d n c i c l e r , / . P h y s . & e v . l e t t e r s i , 206 (1958) .

20. J . J . C o r r i g o n , S .F . S inger and J .Dwetn ick , Phys .Rev. l e t t e r s , i , 104 (1958) -

21. J . R . W i n c a l e r , L.H, P e t e r s o n , K . H o f f r s a n , and E .Ar ro ldy J . G e o p h y s . f i e s . ^ , 685 ( 1 9 5 9 ) .

THncon

•H

}*5° Tfitscopr

I W A ^

THCiCOPt

4

I I - ' a n lo it « /i ic MOUf?i /N a.M.T ptficenT Houmv pev^/ztncNS o/^ CUMK St, Meu^

iHTENSiry ar cmMA/rc on rrr, i f , nrtp nittr '9tf

I l l t h e i n t e n s i t y of the me son ic component a t Guimarg

( c u t o f f . r i g i d i t y 9 . 5 &ev., 2700 m. a i t . ) a s s o c i a t e d

wi th a s o l a r f l a r e of impor tance 2 on Jiine 19» 1958.

f h e r e s u l t s have been r e p o r t e d e a r l i e r , Yadav e t . a l . n n

( i960) , U n f o r t u n a t e l y our n e u t r o n moni to r was

not i n o p e r a t i o n t h a t dg^, o t h e r w i s e t h e i n f o r m a t i o n

would have been more i n t e r e s t i n g . At t h a t t ime our

two narrovy-angle t e l e s c o p e s , h a v i n g aemi -ang les 7°

and 14.5® i n t h e H.S. p l ane ana 45° each i n the E-ti

p l a n e , were a l so working i n a d d i t i o n to t h e meson

c u b i c a l t e l e s c o p e . The f l a r e was r e p o r t e d by Kodai -

k ^ a l Sojlfar o b s e r v a t o r y and i t s t a r t e d a t 0212 h r s . ,

r e a c h e d i t s maximum a t 0218 h r s . , and ended a t 0257

h r s . , &.M2. o r U . f . P u l l d e t a i l s about t h i s f l a r e

a re g i v e n i n Table 29.

The Gulmarg ( l o n g i t u d e 527^2) l o c a l t ime

co r r e spond ing to 0212 U . T , , i s 0726 h r s . which i s

i n t h e 0900 h r . zone.

Ho c o r r e c t i o n was a p p l i e d to t h e da^a and t h e

p e r c e n t d e v i a t i o n of i n t e n s i t y every hour from the

d a i l y mean has been p l o t t e d i n P i g . 55 . £>ercentage

i n c r e a s e due to the f l a r e h a s been saown i n Table 50,

22. R.S . Yadav, e t . a l . I n d i a n J .Met Geophys.11.109(1960)

112

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113

f o r the d i f f e r e a t t e l e s c o p e s , f k e d a t a eo r r e spoada

to a day b e f o r e and a day a f t e r t h e f l a r s . We see

from f i g , 35 t h a t t he i n x e n s i t y r e a c h e s a maximua

a t about 0300 h r s , B . f . whi le t h e f l a r e reac&ed i t s

peak a t 0218 h r s . U . f . I t shows t h a t cosmic-rasr

t n t e n a i t y maximiam h a s been d e l a t e d by more t h a n h a l f

an h o u r , f h i s mag^^tade of d e l ^ i s o f t h e same o r d e r

a s t h a t i n the ca se of f l a r e s of l a r g e r impor t ance .

f a r t h e r , we see t h a t t he e f f e c t i s a o r e

pronounced i n t h e case of the na r row-ang le t e l e s c o p e

{semi -ang le T®). Sefcido e t . a l . (1950)^^ a l s o found

t h a t t he e f f e c t i s l a r g e f o r nar row-angle t e l e s c o p e s ,

f h e cause of t h i s i n c r e a s e ^dith a p e r t u r e , a c c o r d i n g to

theja, i s t h a t d e t e c t o r s of v e r t i c a l n a r r o w - a n g l e s

admit p a r t i c l e s s of lower energy t h a n t h o s e with wider

a n g l e s . Eenc@,> we can conclude t h a t t h e phenomena i s

h i g h l y energy dependent , and t h e i n c r e a s e i s g r e a t e r

i n t h e lower end of t h e energy s p e c t r m .

6 . 2 ISfLPEMCE m SALL fLASES QS gaS MESOS i g f M S X f i maoRmB i f HiaHSR ammm&tiQ

I h s comparison of z ' e s u i t s f o r l a r g e and

25« X.Sek ido , M.Kod^a , ana f . X a g i , a e p . I n o s p h e r e Ees^^apan, £t 207 ( 1 9 5 0 ) .

11.4 smal l a o l a r f l a r - e s shows t h a t t he g e n e r a l f e a t u r e s

of the e o s a i c - r e y i n c r e a s e s ai'e some vtiat s i m i l a r .

Since i n c r e a s e of cosmic r ay i n t e n s i t y h a s not

been found to occur vdth e l l s o l a r f l a r e s a n a t u r a l

q u e s t i o n t h a t comes t o mind i s whether only c e r t e d n

f l a r e s produce eosmic - rays which e v e n t u a l l y r e a c h

the e a r t h , o r our o b s e r v a t i o n s a re too i n s e n s i t i v e ,

too l o c a l i z e d and a t t u n e d t o too h igh an energy t h a t

we cannot d e t e o t t h e e f f e c t i n a l l t h e c a s e s , f o

r e s o l v e t h i s , t o looic f o r small cosmic- ray

i n c r e a s e s a t t h e t ime of small s o l a r f l a r e s , f i r r o r

and otb^ers adopted a s t a t i s t i c a l approach .

Using the superimposed epoch method, f i r r o r demons-

t r a t e d t h a t f o r f l a r e s f o r which t h e o b s e r v a t i o n p o i n t

(Cliinax-48^11) was i n t h e 0900 h r , zone, t h e r e was an

i n c r e a s e o f n e a r l y i n n e u t r o n i n t e n s i t y , whi le f o r

f l a r e s i n o t h e r zones the changes i n i n t e n s i t y 9/as w i t h i n

s t a t i s t i c a l e r r o r , f h e d a t a used was c o r r e c t e d f o r

d i u r n a l e f f e c t .

S ince f i r r o r * s a n a l y s i s p e r t a i n e d to a s i n g l e

s t a t i o n and to a p e r i o d of minimum s o l a r a c t i v i t y

f o r n e u t r o n i n t e n s i t y , we cons ide red i t wor thwhi le

G o n t d . . .

15

t o ana lyze meson d a t a c o l l e c t e d durir ig the IGT

p e r i o d f o r t h r e e s t a t i o n s of d i f f e r e n t l a t i t u d e s .

So la r f l a r e d a t a used Dy u s have been t a k e n from

t h e J o u r n a l of S c i e n t i f i c and I n d u s t r i a l Eesearoh

(1958) . f h e p r e s s u r e c o r r e c t e d d a t a of a e s o n

i n t e n s i t y of h i ^ i l a t i t u d e s t a t i o n s Ottawa ( X - S ?

C h u r c h i l l ( X=70®1) and R e s o l u t e ( X was

s u p p l i e d t o u s by Dr. D .C. lose of t h e JSational Kesearch

c o u n c i l , Ot tawa 2, Canada, f h e e f f e c t of t h e diurn&l

v a r i a t i o n wqs r eaoved from the d a t a , b e f o r e p roceed ing

wi th superimposed a n a l y s i s , f h e d a t a f o r a l l the

a v a i l a b l e smal l s o l a r f l a r e d ^ s were added f o r t h e

y e a r 1958, and the averaged d a t a , o b t a i n e d t h e r e b y

were s u b j e c t e d to herTaonic a n a l y s i s . 2he d i u r n a l

v a r i a t i o n ampl i tude and phase t h u s o b t a i n e d a r e g i v e n

i n f a b l e 31. ®h® c o n t r i b u t i o n f o r d i f f e r e n t b ihoura

Was o b t a i n e d f ro® t h e r e l a t i o n .

Y^ = A s i n ( e -j- 4»)

latere I^i d i u r n a l c o n t r i b u t i o n f o r the n^^

b i h o a r , 8 assumes d i f f e r e n t v a l a o s f rom 0 to 530°

i n s t e p s of 30^ depending upon and A and <4>

axe the afiiplitu.de and ph<ase of the d i u r n a l component.

* See appendix - 3 .

r-f ifS 1 I

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S O H Hi OS f-i O +» 09

CO +» Si <S> o o

f l ie d a t a of each s t a t i o n t i ius c o r r e c t e d f o r

tJie d i u r n a l v a r i a t i o a was r e t a b l e d , c a l l i n g t a e

b ihour d u r i n g wMcli t he f lax 'e o c c u r r e d as zero

h o u r . S i m i l a r d a t a of s t a t i o n s was t hen a r r anged

a t two hour i n t e r v a l s on e i t h e r s i d e of the zero h o u r ,

The average va lue of the c o s i a i c - r a j i n t e n s i t y i s found

f o r ©ach b ihqu r i n d i v i d a a l l j and t h e n the p e r c e n t a g e

d e v i a t i o n f o r each bihoux l a c a l c u l a t e d and p l o t t e d

on a graph a g a i n s t t he co r r e spond ing b i h o u r . With

t h i s method we examined t h e e f f e c t of the smal l s o l a r

f l a r e s of impor tance 1 and 2, r e p o r t e d da r i ng t h e p e r i o d

J a n . to Aug., 1958, o n meson i n t e n s i t y r e c o r d e d a t

Ottawa ( > C h u r c h i l l •( X , and R e s o l u t e

( X 2he r e s u l t s a r e p l o t t e d i n H g . 54. f rom

the cu rves i n F ig . 34, I t i s c l e a r t h a t t he meson

i n t e n s i t y d a t a do no t shovs any i n c r e a s e i n t h e i n t e n s i t y

^hen summed up f o r f l a r e s of impor tance 2 and 1 even

t h o u ^ t h e s t a t i o n s were s i t u a t e d a t h i ^ l a t i t u d e s .

S i m i l a r a n s d y s i s was c a r r i e d ou t f o r xhe

f l a r e s of i s p o r t a n c e 2 o n l y , xhe number of such

e v e n t s i s sttie>l.ler a s seen i n s ^ p e n d i x . . 3 . . . , I h e

r e s u l t s of t h i s a n a l y s i s were p l o t t e d i n Fife. 55 .

One may say t h a t a f a l l i n i n t e n s i t y p r i o r to t h e

f l a r e o r t h e aero hoar i s g e n e r a l l y o b s e r v e d . However,

-oz

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118

t h e i n c r e a s e s of i n t e n s i t y which f o l l o w a re w i t h i n

the s t a t i s t i c a l error. Hence we do not f i n d a i ^

i n c r e a s e of mesoji i n t e n s i t y c o r r e s p o n d i n g t o s o l a r

f l a r e s of impor tance 2.

Oar r e s u l t s a r e i n agreement of wi th tiaose of

f o v a e and Lockwood (1959)^^ , S-aainer (1960)^^ and 26

Chaloupi:a e t . a l . (1960) and K-oloaieyeta and

Sergeeva

Our n e g a t i v e r e s u l t s f o r t he p e r i o d of

maximum s o l a r a c t i v i t y , compared with t h e i n c r e a s e

found by K l r r o r du r ing a p e r i o d of ainimiam s o l a r

a c t i v i t y l e a d us to t h i n k t h a t when low energy

p a r t i c l e s a re cu t o f f i n a p e r i o d of maximum s o l a r

a c t i v i t y , t h e e f f e c t of m a l l s o l a r f l a r e s

i s not s i g n i f i c a n t * I t shoi'^s t h a t -perhaps p a r t i c l e s

s e n t ou t by smal l s o l a r flggpes axe of very low energy .

24. and J.A.Lodcwoodj Phya, Rev. 113« 641(1959) . ^ ^ ^ ^

25. l . S . K a a i n e r , Srans .Xa M ( S e r . P i z . ) 1 ,92 ,148 (1960) 26. P .Ghaloupka, i i . J i r e s , and !!il.Kov9alsk.i, Caech .Phys . J

1 0 f W ( I 9 6 0 ) . 27. E.V.KolomeyetB, and G.A.Bergeeva, ^ R e s u l t s of IGl

(Moscow), Cosmic-rays No.4t152, ( I 9 6 I ) . 26. B . a . Hoka, Z .Matur fo rsch , 0 517 ( 1 9 5 0 ) . 29. l e . S . G l o k o v a j Srudy. S i i sm, 8, 53 ( 1 9 5 2 ) .

19

A p o s s i b l e r e a s o n f o r our n e g a t i v e r e s u l t

may h.owever be t h a t we feave averaged over* 2-iiour

p e r i o d s , whereas t k s d u r a t i o n of -siaall f l a r e s i s

of tiae o r d e r of iaalf an liour aad even tiie d e f i n i t e l y

obse rved peals i a F i g . 33 l a s t e d oa ly one k o u r . A

f i n e r a n a l y s i s , i f d a t a were a v a i l a b l e , m ^ snow a

p o s i t i v e r e s u l t .

CHAggSS—YII.

w m O f g H E G H A R A G f E R Q f Q Q S a i O - E A Y I B f B I S I f l y A & I A n Q i r S D q E l E f g s o l a r a b b M A a S E I g l C I)IS3!q£BAHG£a ^

A mmber of l a v e s t i g a t i o m have beea r e p o r t e d

i n l i t e r a t u r e oa. t he c h a r a c t e r of eosmic r ay i n t e n s i t y

y a r i a t i o n s dtariiig the l a r g e s o l a r f l a r e s and the

i n t e n s e magne t i c s to rms , but very l i t t l e i n f o r m a t i o n

i s a v a i l a b l e f o r v a r i a t i o n s dur ing t h e s m a l l e r s o l a r

f l a r e s , and a s s o c i a t e d magnet ic s to rms .

I n t h i s c h r ^ t e r we have d i s c u s s e d t h e e f f e c t

of 86 small s o l a r f l a r e s ( r e p o r t e d by Kodaikanal and

Sizamiah Obse rva to ry , I n d i a , du r ing J u l y , 1957 t o

August 1958) of impor tance 1 and 2 and t h e a s s o c i a t e d

m a g m t i e s torms on cosmic -ray meson i n t e n s i t y ,

r e c o r d e d a t Ottawa ( X « 5 7 ° I ) , <3hurchlll ( \ = 70°S)

and R e s o l u t e ( A d a r i n g 1957-58, by t h e 3 superimposed epoch method o f Ghree (1915) « H i ^

l a t i t u d e s t a t i o n s were chosen f o r a n a l y s i s because

i n t h i s case t h e e f f e c t i s more pronounced.

t A p a r t of t h i s i n v e s t i g a t i o n i s p u b l i s h e d i n t h e Hat . Acad. Sci ( I n d i a ) , Sec.A<1964) -

2 . J . S c i I n d u s t r . E e s . , 17A. 105 (1958) . 3 .C.Ghree , P h i l . T r a n s . Eoy. Soc . , A«212, 7 6 , ( 1 9 1 5 ) .

We kave jalso t r i e d to s tudy t h e p r o f i l e s of

i n t e a ^ t y v a r i a t i o n s , due to such magne t i c s torms t o

examine t h e . p r o p e r t i e s of c o r p u s c u l a r s t r eams and

the n a t u r e of l^aeir i n t e r a c t i o n wi th t h e e a r t h .

f h e f o l l o w i n g p o i n t s were p a r t i c u l a r l y kep t

i n view s -

(!)• The e f f e c t ' o f t hose smal l s o l a r f l a r e s , on

eosmic- ray i n t e n s i t y which a r e f o l l o w e d by m a g i ^ t i c

a t o m s and a l s o of t h o s e which a re no t f o l l o w e d by

magnet ic s t o rms .

( 2 ) . f h e e f f e c t of smal l s o l a r f l a r e s and t h e i r

a s s o c i a t e d magnet ic s torms a t d i f f e r e n t l a t i t u d e s

aad on d ^ s of d i f f e r e n t sunspot a c t i v i t y .

( 5 ) . The e f f e c t of s o l a r f l a r e s of d i f f e r e n t

impor tance on c o ^ i c r ay i n t e n s i t y .

( 4 ) . A s s o c i a t i o n between t h e s o l a r phenomena

and subsequent geomagnetic e f f e c t s , which a re

s t u d i e d by c o n s i d e r i n g t h e v a l u e s o f t h e geomagnetic

i n d i c e s G^.

The d a t a of geomagnet ic s torms and C^ v a l u e s

u s e d h e r e a r e tsifcen f rom J .Geophya. Ees , 1957

and 1958, For 1958, t h e v a l u e s of G^ a r e t a k e n

122

from t h e d a t a s u p p l i e d by Br. J . B a r t l e a , Zuricli

O b s e r v a t o r y , Swit izer laad.

7 . 1 ffiSfHQD OF AMALXSIS

fi^e 4 a i l j average c o a a i c - r a y meson i n t e n s i t y

was c a l c u l a t e d f o r each of t h e seven days b e f o r e t h e

f l a r e and seven days a f t e r i t . The average of t h e

14 days tfiOcen t o g e t h e r was t h e n compeared v?ith t h e

d a i l y aicerage and p e r c e n t a g e d e v i a t i o n s c a l c u l a t e d .

7 . 2 ASSQClAaiOI BEi'VilEEH MB DAILY MEAS MBaOH ISfEMSl!!!! ASP SOLAR fLAE£S gOLLOV EB ASD 502 fOLLQWEB BX ffiA&H£fIC>SfgiiaS s

The meson i n t e n s i t y a t Ottavtfa i s examined

from t h e p o i n t of view as d i s c u s s e d below

E i ^ t y s i x f l a r e s obse rved d u r i n g 1957-58

a r e d i v i d e d i n t o two ^ o u p s A and B. Group A

c o n t a i n s t h o s e f l a r e s which a r e fo l l owed by Magne t ic

s to rms .

I f t h e i n t e r v a l , A t , between t h e o c c u r r e n c e o f

s o l a r f l a r e s and t h e geomagnetic s to rms i s l e s s t h a n

5 d ^ s , t h e n t h e f l a r e i s c o n s i d e r e d t o be f o l l o w e d

by a magne t ic s torm, and i s pu t i n group A. I f t h e

de lay i s greatJ^^han 5 days , t h e f l a r e i s c o n s i d e r e d

23

t o be no t f o l l o w e d by a m a g n e t i c s torm and i s p u t

i n groap B. I n t h i s way 76 f l a r e s f a l l i n group A

and 10 f a l l i n group B.

Tke r e s u l t s o b t a i n e d a r e shown i n f i g . 36 .

f h e curve f o r t h e f l a r e s f o l l o w e d by m a g n e t i c s t o r m s

shows t h e p e c t i l i a r f e a t u r e t h a t t h e average meson

i n t e n s i t y i n c r e a s e s even b e f o r e t h e f l a r e day . She

maximm i n c r e a s e i s about 0 . 1 7 i 0 . 0 3 6 ^ and i t o c c u r s

abou t two days b e f o r e t h e f l a r e . A f t e r t h e f l a r e ,

t h e i n t e n s i t y f a l l s below i t s ave rage v a l u e . I t

c o n t i n u e s t o f a l l u n t i l t h e minimum i s r e a c h e d two

t o t h r e e days a f t e r t h e f l a r e . She minimum i s abou t

- 0 . 2 4 • 0.056?&.

I n t h e ease o f t h e f l a r e s which a r e n o t

f o l l o w e d by m a g n e t i c s t o r m s , t h e meson i n t e n s i t y

shows a t r e n d t h a t i s so to s a y , i n phase o p p o s i t i o n

t o t h e e a r l i e r c a s e . Average i n t e n s i t y r e a d i e s a

minimum of abou t ~ 0 . 8 1 ± 0 . 0 4 ^ n e a r l y two days b e f o r e

t h e f l a r e . I t r e t u r n s t o i t s normal v a l u e and i n c r e a s e s

to about 4-0.37 i 0 . 0 4 ^ two t o t h r e e days a f t e r t h e

f l a r e .

Our r e s u l t s a r e i n g e n e r a l agreement w i t h

t h o s e of Hogg (1949)^ who bas^d h i s o b s e r v a t i o n s

4 . A.E.Eogg, Memoirs o f t h e common w e a l t h o b s e r v a t o r y Canbe r ra , No.10 ( 1 9 4 9 ) .

/ye.Si //j-^/p/re^ sv/'d-iffotcf> VTLuei of ôff

7 u / t , - s B f ^ w e / 7 / f o / f ^ r e ^ j r F i / 7 / r e i ^ h k m

>t/tt ^îioivro />/ro AôT ftttoh/eo

124

on l a r g e s o l a r f l a r e s ,

7 .5 VARlAglOH Qi' COSMIC RAI MESQH WI H SOLAR FLAilES {IX)LLQW£I) BY MAGF^flC SfOfiM) DlfFE&SIf LAglTPJDDS.

On t h e b a s i s of 41 f l a r e s , f i g . 57 and Sab le

52 h a s been c o n s t r u c t e d .

f rom f i g . 57» i t i s no ted t h a t meson i n t e n s i t y

does z ^ t show ax^ s i g n i f i c a n t i n c r e a s e on t h e f l a r e

d ^ du r ing t h e p e r i o d exeaained h e r e a t any l a t i t u d e .

I t means t h a t du r ing t h e p e r i o d J a n . t o Aug. 1958

(which i s t h e p e r i o d of maximum sunspot a c t i v i t y )

meson i n t e n s i t y does no t show aiiy i n c r e a s e a a s o c i a t e d

wi th ®aall sol^tr f l a r e s of impor tance 1 and 2, a t

any l a t i t u d e .

Kaminer (1960)^ , Towle and Lockwood (1959)^

and S h i e l m e t t e e t . a l . (1960J a l s o a r r i v e d a t t h e

same r e s u l t .

5. H.S. Kaminer, SJrans. Ya FAN, 92 & 148(1960)} P r o c . lOI'AP, Moscow Gonf. ( 1959 ) , V o l . 4 , 42 o r 44.

6 . L . C . f o w l e , and J.A.Iiockwood, Phys . Sev. 115. 691 , ® ( 1 9 5 9 ) .

7 . B . G h i e l m e t t e , J .U.Anderson , J . E . Cardoso, &. fflanaano, J . ( J . E o e d e r e r , J . a . and R. Santochor Huovo. Cimento, 1^ , 87 (1960) .

1-0/iYS B£ro/ig /9HO THf F l f t m 0/9y.

125

57 a l s o shows t h a t a f t e r t he f l a r e day,

mesoa i n t e n s i t y d e c r e a s e s below t h e normal l e v e l ,

rea<aaes the minimiaa and t h e n s lowly r e c o v e r s i t s

normal l e v e l , ®his i s n o t i c e d a t a l l t h e t h r e e

l a t i t u d e s examined h e r e . The magnitude of the dip

(maxiBraffi dec rease ) and i t s t ime of occi i r rence a t

d i f f e r e n t l a t i t u d e s a re g iven i n f a b l e 32. From

t h e r e s u l t s g i v e n i n f a b l e 32, i t i s e v i d e n t t h a t

t h e magnitude of t h e d ip i s a lmost c o n s t a n t on a l l

t h e t h r e e l a t i t u d e s from 5?° t o 83®H. But t h e t ime

of o c c u r r e n c e of t h e d ip i n c r e a s e s a s t h e l a t i t u d e

i n c r e a s e s . She d ip becomes more and more sha l low

a s we move towards t h e p o l e , f h i s i n d i c a t e s t h a t

the p r o f i l e of t h e dip and i t s t ime of occu r r ence

a r e r i ^ d i t y dependent . Webber (1962)^ a l s o d i s e u s s e d

cosmic-ray d e c r e a s e s a s s o c i a t e d with l a r g e magne t i c

s torms and showed a very pronounced r i g i d i t y dependence

e x t e n d i n g a t l e a s t over t h e r ange 1 - 3 0 Gev.

Another s ign i f i cgya t p o i n t from t h e s e cu rves i s

t h a t t h e r e i s an i n c r e a s e i n meson i n t e n s i t y b e f o r e

the f l a r e d ^ on a l l t h e l a t i t u d e s examined h e r e , f h i s

i n c r e a s e occu r s on t h e f i r s t ds^ b e f o r e t h e f l a r e day

8 . » .H. \ n " W I?")-

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on fie s o l u t e (83*^5) and Ciii ircii i l l (75®ir), whi le a t

Ot tawa i t o c c u r s on 2nd day be fo re the f l a r e

day.

7 . 4 ASSQCIAflOH B£fW££H yAHlA2I0HS Of M£SQM IITEHSIgr AND TES: XMPQ&fANGB Qg fH£ SOLAR F L ^ S S .

76 f l a r e s wMeh were f o l l o w e d by magnet ic

s torms i n tvso groups «e re s t u d i e d t o see t h e a s s o -

c i a t i o n between t h e impor tance o f t h e f l a r e s and t h e

<Siaraeter of t he cosmic r a y i n t e n s i t y v a r i a t i o n s , f h e

f i r s t group h a s 12 f l a r e s of impor tance 2, and t h e

second group c o n t a i n s 64 f l a r e s of i m p o r t ^ c e I t

obse rved d u r i n g t h e y e a r 1957-58 . f h e r e s u l t s a r e

shown i n F i g . 58 and Sab le 55. I t i s aeen t h a t t h e r e

i s no i n c r e a s e of meson i n t e n s i t y on t h e f l a r e day jNfo r

any dgy j u s t a f t e r t h e f l a r e djsy.

f h e r e s i s t s , which a r e based on a s l i ^ t l y

d i f f e r e n t s t u d y , a re i n agreement with t h o s e d i s c u s s e d

i n t h e c h a p t e r and a l s o wi th t h e o t h e r i n v e s t i -

g a t o r s .

f h e s i g n i f i c a n t p o i n t s i n t h e c h a r a c t e r of

meson i n t e n s i t y v a r i a t i o n s shown i n f i g . 58 a re as

f o l l o w s s -

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(1) Both i n tiie case of the f l a r e s of impor tance

2 and 1 , meson i n t e n s i t y siiows a s i g n i f i c a n t dec r ea se

on 2nd day a f t e r the f l a r e day. f k e magni tude of t h e

dec rease ( d i p ) f o r f l a r e s of impor tance 2 i s - l .S+O.OSS^

and i t o c c u r s on the second day f o l l o w i n g t h e f l a r e .

Bor f l a r e s of Importance 1» the magni tude of t h e d e c r e a s e

i s - 0 . 5 2 ± 0 .037^ and i t o c c u r s on t h e second day

a f t e r t he f l a r e ,

(2 ) Both i n t h e case of t h e f l a r e s of impor tance

2 and 1 , meson i n t e n s i t y shows a s i @ 3 l f i c a n t i n c r e a s e

on the 2nd day p r i o r t o t h e f l a r e and we c a l l t h i s

i n c r e a s e ^ ' P r e - f l a r e i n c r e a s e " . The magni tude of t h e s e

p r e - f l a r e i n c r e a s e s f o r t h e f l a r e s of impor tance 2 and

1 a r e -1-1.35 + 0 .085^ and "I-0.75 0 .057^ r e s p e c t i v e l y .

(3) During t h e p e r i o d J u l y 1957 to August 1958,

\i!^ich i s t h e p e r i o d of m i simum s o l a r a c t i v i t y , i t i s

found t h a t t h e magni tude of t h e dec rease of meson

i n t e n s i t y a f t e r t he f l a r e day a s we l l as the p r e - f l a r e

i n c r e a s e i s l a r g e r i n t h e case of t h e f l a r e s of

impor tance 2 t h a n i n t h e case of t h e f l a r e s of

impor tance But t h e t ime of occu r r ence of the

maximum d e c r e a s e s ( d i p ) and maximum p r e - f l a r e i n c r e a s e

i s t he same f o r t h e f l a r e s of impor tance 2 as of

impor tance 1 .

7 . 3 aBLA!PlQlSHlP BBgWESa m S ?ARIA£I0IS Qg MjESOI IMfSHSIfl AMD SHE ^OSSfOi' ACf l¥ I$ I .

f o obse rve t h e e f f e c t of s o l ^ f l a r e s ( c o n s i -

dered oa ly t h o s e f o l l o w e d by magne t ic s torms) of

l e s s e r impor tance on meson i n t e n s i t y d u r i n g t h e

t ime of d i f f e r e n t sunspot a c t i v i t y , t h e p e r i o d

1957-58 h a s t>een d iv ided i n t o t h r e e g roups . On t h e

b a s i s o f t h e sui i -spot iHambers.

( i ) f h e f i r s t group e x t e n d s from J u l y to

Beceaber 1957.

( i i ) The second group (which i s t he sum of

the f i r s t end second) ex t ends f rom J u l y

1957 t o August , 1958 and

( i i i ) The t h i r d group from January to August ,

1958.

Daily mean meson i n t e n s i t y of Ottawa h a s been

ana lysed f o r t h e s e t h r e e groups and the r e s u l t s o b t a i n e d

are* g i v e n i n 2ab l e 54, and p l o t t e d i n f i g . 59 .

f h e s i g n i f i c a n t p o i n t s i n t h e c h a r a c t e r of

meson i n t e n s i t y v a r i a t i o n s shown i n 2'ig. 39 a r e

a s f o l l o w s s -

( i ) Form t h e t a b l e 34 and F ig . 59, i t i s c l e a r

t h a t f o r a l l t h e t h r e e ^ o u p s d i s c u s s e d above, t h e r e

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132

i s a d ip wMcb o c c u r s between two o r t h r e e days a f t e r

the f l a r e day. The magni tudes of t h i s d ip f o r t h e

f i r s t , second and t h i r d group a r e , - 1 . 0 4 t 0 , 0 4 4 ^ ,

- 0 . 5 7 t 0 .034^ and - 0 . 2 ? + 0 . 0 4 6 ^ r e s p e c t i v e l y . Th i s

shows t h a t t h e magnitude o f t h e dec rease ( d i p ) of a e s o a

i n t e n s i t y i n c r e a s e s a s the sunspot a c t i v i t y i n c r e a s e s ,

bu t i t s t ime of occur rence i s a lmost c o n s t a n t d u r i n g

t h e p e r i o d of d i f f e r e n t sunspot a c t i v i t i e s .

( i i ) Por al.l t h e t h r e e grouj js , meson i n t e n s i t y

shows a s i g n i f i c a n t i n c r e a s e ( p r e - f l a r e , i n c r e a s e )

on t h e 2nd day p r i o r to t h e f l a r e day. Ihe magiiitmdes

of t h i s i n c r e a s e f o r t h e t h r e e groups a re 1 . 4 2 + 0.004?^

1 .19 t O . O 3 0 t and 0 .49 ± 0 .04^^ r e s p e c t i v e l y , from

t h e s e r e s u l t s one may say t h a t t h e magnitude of the

p r e - f l a r e i n c r e a s e a l s o i n c r e a s e s a s t h e sunspot

a c t i v i t y i n c r e a s e s .

7 . 6 a£IiA!P10HSIiIg BBgtfBEII aiflALL SQLA£ FLMES M B GBOMAaS iPIC BiSlD£BA10£5.

!Eh@ r e l a t i o n between smal l s o l a r f l a r e s and

the geomegnetic e f f e c t s i s s t u d i e d by the fihre®

method, c o n s i d e r i n g t h e geomagnetic i n d i c e s C^ f o r

t h e da^rg b e f o r e and a f t e r t h e f l a r e e v e n t s , f h e

r e l a t i o n betv/een G and f l a r e s of impor tance 2 ( n i n e

cases ) and of impor tance 1 (57 cases) a re examined

33

s e p a r a t e l y f o r the pe r iod J a n . to Aug., 1958 and

the r e s u l t s a re shown i n f i g . 40.

I n the case of t he f l a r e s of importance 2,

the average superlmpoaed v a l u e s ( i n of C show i r

a l a r g e i n c r e a s e {s tar t ing from the f i r s t da^ a f t e r t h e

f l a r e and r e a c h i n g the peak value on the 2nd da^

a f t e r t he f l a r e . I n the case of the f l a r e s of impor -

t ance 1 , the average superimposed va lue of ( i n fo)

s t a r t s i n c r e a s i n g on the f l a r e d ^ and shows a peak

value on the f i r s t ds^ a f t e r the f l a r e ,

She magnitude of i n c r e a s e f o r t he peak va lue

of G^ i s q u i t e l a r g e i n the case of t h e f l a r e s of

impor tance 2 . 3!he delg^ i s a l so l a r g e r i n t h e former

case t h a n i n the l a t t e r . Since t h e former i s based

only on 9 c a s e s , t h e s e c o n c l u s i o n s a r e only of a

t e n t a t i v e n a t u r e . However, i t i s c e r t a i n t h a t t h e r e i s

an i n c r e a s e i n C^ a f t e r s o l a r f l a r e s .

Similar r e l a t i o n was a l so observed by Dodson

and Hedeman (1958)^considering the solar f l a r e s of a l l

importances during the period J a n . 1949 to Apri l ,

1956 (115 e a s e s ) , and by Denisse (1952)^^ and Simon

(1954)^^ .

9 . H.M.Iiodson, and JS.&.Hedaman, ^ J.G-eophys., Res .65 . e 77 (1958) .

1 0 . J . f . D ^ n i s e e , Ann. Geophys., 8 , 55. (1962) . 11. J . f . i i m o n , P h y s . , Hev. , l i , ~ 4 4 7 (1954) .

c./

\ /

^ "iOLtf" A i. ft hi i / /Mf-Of^l / \ f y c 'Of u i '

/ \

\ / \ V

1 I V

1 _J 1 1 1 1 1——1

( J7 C^J/I^

FKi AO /tei/tr/on aeTi%ff£/v T//e soLaa fîivê />/ro

oeoM/7oî£r/c D/iTL/f/O'^^css U) ca/fvfs li-B tme /fei/irioM Bem££M Sl/P£/!P<>ieD k'Ml/^S Of^ Cp /IMO SOL/V/t ft^ê o^

34

7 . 7 fME BBLAl BETWEEE mM QCC0a&£HQl 0? A SOLAR FhARE. ABB TEB STA&f Of TH£- ASSOCIATE]) MMBBglO SSORMS .

S t a t i s t i c a l d a t a t o s tudy t h e e f f e c t i s g i v e n

i n l iable 35 . The average de lay i a oux ease i s one

day and 5 Hours,, The f r e q u e n c y d i s t r i b u t i o n i s

shown i n F i g . 41 . I n Table 35, the delay )

i s c a l c u l a t e d i n u n i t s of a whole day ( d i f f e r e n c e o n

c a l e n d e r d a t e s ) r a t h e r t h a n i n t h e e x a c t t i m e

i n t e r v a l i n hocira between t h e s t a r t of f l a r e s and

stoffiBs.

7 . 8 msCUSSIOS AMB lMT£RPRE*gATI01 QW .ElPSRIMBMrAI, EESULg J -

The d e c r e a s e of meson i n t e n s i t y f o l l o w i n g

f l a r e s w i t h magne t i c s to rms shows a s s o c i a t i o n be tween

magne t i c s to rms and cosmic r a y d e c r e a s e , f h i s

i n d i c a t e s t h a t b o t h have a coiamon c a u s e . I n t h e p a s t

y e a r s many modesls have been p roposed t o e x p l a i n t h e

cause of t h e s e Porbush type cosmic - r ay d e c r e a s e s ,

12 Chapffijm (1937) s u g g e s t e d t h a t t h e s e may be

e x p l a i n e d on the b a s i s of a r i n g - c u r r e n t of t h e

12 . S.Ghapman, S a t u r e , 140, 423 ( 1 9 3 7 ) .

' I

r/c. oarfftaurtof* cs-rt^eet^

At ^SCL/ift At pc^'H'ii^f^rs 7He //vrsMi rfI. ah: rn.een

THe 4-^/c ^ o.'-- oea/^^a^rr/c S70fi!M.

135

^ ^ ^ ^ ^ <M r^

to 0 m o

O

a> %

«H <H U O

a r-l g o

in

•e*

t<A 8 3 ^ try (<\

•P rt O r4 to

nS O •H u 0 p*

<X3 (A I Ih-m

oo c-

0}

5

136

p o s t u l a t e d toy Chapman and F e r r a r o i n t l i e i r t h e o r y 1

of m a g n e t i c s t o n n s . Hagaahiaa ( 1 9 5 1 ) , (1955)

m o d i f i e d t h i s r i n g c u r r e n t h y p o t h e s i s . But t h i s r i n g

c u r r e n t h y p o t h e s i s o r any change i n t h e e a r t h ' s d i p o l e

f i e l d cannot e x p l a i n c o s a a i c - r ^ d e c r e a s e s o b s e r v e d

« 3 a t p o l a r l a t i t u d e s , C h u r c h i l l (70^!f) and R e s o l u t e

d u r i n g vhe p e r i o d 1957-58 ( p e r i o d of maximum

s o l a r a c t i v i t y ) and a l s o c o s m i c - r a y d e c r e a s e s o b s e r v e d

a t ' Ihule i n 1951. 'Ihus t h e r i n g c u r r e n t

i j y p o t h e s i s f o r coacaic r a y d e c r e a s e s i s u n t e n a b l e .

M o r r i s o n (1956)^^ e x p l a i n e d t h e c o s m i c - r a y

d e c r e a s e s on. t h e b a s i s of t h e d i f f a s i o n a o d e l . M o r r i s o n ' a

model h a s been ex tended by b a r k e r (1956)^^ and a l s o

by S inge r ( 1 9 5 7 ) ^ ^ . But one d i f f i c u l t y wi th t h i s

model i s t h a t i t r e q u i r e s l a r g e m a g n e t i c f i e l d s t o

a f f e c t c o s m i c - r a y s of r e l e v a n t e n e r g i e s , ( a b o u t 30

G e v . ) . Another d i f f i c u l t y i s t h a t i t l e a d s t o l a r g e

l a t i t u d e dependence of t h e cosmic - r ay d e c r e a s e s . On

t h e c o n t r a r y , t h e o b s e r v e d l a t i t u d e e f f e c t i s v e r y

smal l and t h e v a r i a t i o n s obse rved i n n e u t r o n c o u n t e r s

a r e not very much g r e a t e r t h a n t h o s e of i o n chambers

o r mea>n t e l e s c o p e s a t s e a l e v e l . 5?his d i f f u s i o n

15 . K . l a g a s h i m a , J .^eomag and ( j -eoe lec t .^ j lOOClgSl ) , J .Geomag. and G e o e l e c t . ^ , 1 4 1 ( 1 9 5 3 ,

1 4 . P . M o r r i s o n , P b y s . & e v . a ^ , 1 3 9 7 ( 1 9 5 6 ) . 15 . S . l .ParjEer, Phys .Eev . lQS , 1518(1956) j l l O j 1445(1958) . 16 . S . F . S i n g e r , Huovo e imento , S u p p l . l l , ( 1 9 5 7 ) $ S ,

Ser 1 ^ , 3 2 6 , 2 3 4 ( 1 9 5 8 ) .

3330del a l s o doee not account f o r t h e i n c r e a s e i n

i n t e n s i t y observed us b e f o r e t h e f l a r e s .

Al fven <194^, 1949)^'^ and Ifagashima (1951,1953)^®

proposed tke e l e c t r i c f i e l d model based on t h e s o l a r

streaBJ. M f v e n sugges ted t h a t t h e dec r ea se i n cosmic-

r ^ i n t e n s i t y i s due t o t h e e l e c t r i c f i e l d «h ich a r i s e s

a s a r e s u l t of the mot ion of t h e s o l a r a o r p u s o u l a r

s t ream through, t h e s o l a r magne t i c f i e l d . According

to t h i s model, t he energy l o s t by a p a r t i c l e c r o s s i n g

the s o l a r s t ream i s ( ¥ M ) b , where V i s t h e s t r e a a

v e l o c i t y , H i s t h e ' F r o z e n - i n " magne t ic f i e l d c a r r i e d

hy t h e s t r e o a , and b i s t h e b r e a d t h of t h e s t r eam.

I 'h i s model h a s been extended by Barnberg and D a t t n e r

(1954)^^ .

This ffiodel ^ s o e x p l a i n s t h e i n c r e a s e s i n

®es©a i n t e n s i t y found by ua t o occur b e f o r e t h e

f l a r e day. Blokh, Glokova and Borman (1959)^^a l so

obse rved smal l i n c r e a s e s i n t h e case of t h e 21.

i n d i v i d u a l magne t ic s to rms . Dorman ( I960) and 22 o t h e r s e x p r e s s e d t h e o p i n i o n t h a t t h i s i n c r e a s e

17. H . l l f v e a , l a t u r e , 1S8^618{1946) ;gh5ra .aev.72 1752(1949) .

18 . K.fifagashima, J .Geomg.Geoelec t . , ^ 1 0 0 ( 1 9 5 0 ) | 1 , 1 4 1 ( 1 9 5 5 ) .

19 . B.A.Burnberg and A . D a t t n e r . , M e l i u s , 6 , 7 5 $ 2 5 4 ( 1 9 5 4 ) . 20. Blokh, Slokova, and Dorman ,C .S .Var i a t i ons .

Underground, s e a - l e v e l and i n S t r a t o s p h e r e , (Moscow),! , ( 1 9 5 9 ) .

21 . L.I.I)®rman,Broc.Moscow Cosmic-ray CJonference V o l . 4 , ( I 9 6 0 ) .

22. P r o c e e d i n g s of t h e Moscow Oosmie-ray c o n f e r e n c e , Vo l .4 , ( I 9 6 0 ) .

i s due to a siiocis: wave from tJie a b r u p t l y approacii i i ig

f a c e of t h e c o r p u s c u l a r beam c a r r y i n g a f r o z e a - l J i

magae t i c f i e l d , f k e p o s s i M l i t y of t h e f o r m a t i o n

of a shock wave by means of tiie f r o n t f a c e ( o r tia©

appro aching f a c e ) of t h e beam ( o r stream) was d i s -

cussed by Singer (1957)^^ who a l so i n v e s t i g a t e d t h e

geomagnetic e f f e c t s of t h i s shock wave on i t s a r r i v a l

a t the e a r t h . H e c e n t l y , t h e a c c e l e r a t i o n of charged

p a r t i c l e s d u r i n g the passage of t h e f r o n t of a shock

wave i n magne t i c plasma has been c o n s i d e r e d i n d e t a i l

by Dorman and F r e i d a a n ( 1 9 5 9 ) a n d Dorman (1960)^^

and Snabaasky (1961)^^ . I t i s shown t h a t i n t h e f r o n t

p a r t of a s o l a r s t ream c a r r y i n g a F r o s e n - i n magne t i c

f i e l d , t h e plasma and the magnet ic f i e l d a r e a p p a r e n t l y

compressed. Hence t h i s eahaaced magnet ic f i e l d w i l l

r e f l e c t t h e chai'ged p a r t i c l e s i n c i d y n t on i t , and

among a l l t he p a r t i c l e s f a l l i n g on t h e s u r f a c e of t h e

e a r t h t h e r e w i l l be a d e f i n i t e f r a c t i o n of t h o s e

23. L . I . Dorman and &. I . Freioman, Problems of Magneto hydro ' dynamics, and plasma

P h y s i c s ( E i g a ) , 77, ( 1 9 5 9 ) . 24. L . I . Dorman, Eoscow, O.K. Gonference , ? o l . 4 ,

132 or 134(1960) . 25. Y.P.Shabansky, 2h. Cksp. t&or , P i a . ^ , 1 1 0 7 ( 1 3 6 1 ) .

p a r t i c l e s t k a t a r e r e f l e c t e d f rom t h e s t r eam.

I n sueh r e f l e c t i o n t h e r e i s a head-on c o l i i s i o m

i n which p a r t i c l e energy inore&aes soate¥?n.at, aad

t h i s should l e a d to an i n c r e a s e In t h e i n t e n s i t y

of cosff l ic-rays on t h e s u r f a c e of t h e e a r t h ,

( i i ) l-iatur® of the p r o f i l e s and the s o l a r s t r e a m .

f h e r e s u l t s d i s c u s s e d i n t h i s c h ^ t e r have

shown t h a t i n thejcase of the f l a r e s f o l l o w e d by

magne t ic s to rms t h e r e i s an i n c r e a s e i n cosmic- ray

s e s o n i n t e n s i t y b e f o r e t h e f l a r e on t h e 2nd day.

ThtB i n c r e a s e i s a l s o n o t i c e d i n t h e case of f l a r e s

of impor tance 2 and 1 and a t d i f f e r e n t l a t i t u d e s ,

f rom t h e o r e t i c a l c o n s i d e r a t i o n developed oy i^riaan

and o t h e r i n v e s t i g a t o r s , i t i s c l e a r t h a t t h i s

i n c r e a s e could occiir on ly i n t h e case of magne t ic

s to rms v^ ich g ive r i s e t o t y p e s I aad I I f a l l i n g p r o f i l e s

( f i g . 42) and the i n c r e a s e should not occtir wi th s t o n a s

of type n i p r o f i l e s (Borman I960) .

f h u s , on a p u r e l y q u a l i t a t i v e o a s i s we can

"broadly s&y t h a t the dec rease p r o f i l e m i c h ise-

obse rved i n i?ig. 36, f o r t he f l a r e s f o l l o w e d by

magne t ic s torms i s e i t h e r of t y p e I or t ype I I , P i g . 4 2 .

Froai f i g . 36 i t seems t h a t t h e dec rease p r o f i l e i s

of t h e t ype I I . i^om t h e curvos i n J±g* which

"TIMt D/F/lRtNl /POSSIBLE 7 ypfs O/^ /'/VOr/Li3 Cf/ C OSMJC .^ y/Y /A/y/TA/S/r y i^/9/e//9r/0/VS

g i v e t}ie|decreasQ p r o f i l e of meson i n t e n s i t y a t

t i i ree d i f f s r e a t l a t i t u d e s , i t seems t k a t i a t h i s

case a l s o the a©crease p r o f i l e s on d i f f e r e n t

l a t i t u d e s a re of t j p e I I . F i g s . 38 and show

t h a t f o r f l a r t ' s of impor tance 2 and 1 and a l ao f o r

f l a r e s aurin^^ feie p e r i o d e f d i f f e r e n t sanspo t

a c t i v i t j , the dec rease p r o f i l e i s of tne type I I .

Ihtts on t h e b a s i s of t h e s e p r o f i l e s , one s a y say

t h a t t h e s e meson i n t e n s i t y d e c r e a s e s eo^e caused

when t h e e a r t h i s enveloped hy t h e I q a d i n g f a c e

of the s t r eam,

( i i i ) SJEGREASS at hL^hm LAI'IIUB^S

i ' i g . 37» shows t h a t t h e p o l a r d e c r e a s e s

seeass t o he both l a r g e r aad wider t h a n t h o s e a t o t h e r

l a t i t u d e s . The r e a s o n f o r t h i s (&& d i s c u s s e d by S inger

.1958} may t h e p resence of t r a j e c t o r y d i s p e r s i o n

v^hich e x i s t s a t a l l o t h e r l a t i t u d e s . " But a t the p o l a r

l a t i t u d e s even a aon-momchrojaate d e t e c t o r ? , l l i

r e c e i v e d a l l primary p a r t i c l e s from t h e ssme d i r e c t i o n .

S inger h e l d thu-t ^he mot ion of the p a r t i c l e s beyond

about 40-eaa : ' th - radi i hecoises c o n t r o l l e d by the i n t e r -

p l a n e t a r y magne t i c f i e l d . I n any c a s e , whatever t h e

cause of t h e fo rbush d e c r e a s e s i t c l e a r l y a f f e c t s a l l

t h e p a r t i c l e s e n t e r i n g t h e pola?^ a e t e c t o r , bu t oa ly

14

a p o r t i o n of t h e p a r t i c l e s a t o t h e r l a t i t u d e s .

T h i s f a c t i n d i c a t e s t h a t t h e p o l a r t e l e s c o p e h a s

the i m p o r t a n t a b i l i t y to look ou t f u r t h e r i n t o

space t h a n t e l e s c o p e s a t o t h e r l a t i t u d e s .

APPBHDIX

f h e u n c o r r e c t e d d a t a of meson i n t e n s i t y f o r

t h e month of November 1958, r e c o r d e d a t Siilmarg

( 24.7®I) i s g iven i n f a b l e 57. f h i s d a t a i s t o

be c o r r e c t e d f o r ba rome te r i c p r e s s u r e u s i n g t h e

f o l l o w i n g e q u a t i o n .

l ^ e r e

I p » b i h o u r l y meson i n t e n s i t y c o r r e c t e d

f o r b a r o m e t e r i c p r e s s u r e .

= Uncor rec t ed bifeourly meson i n t e n s i t y .

B a 2he p r e s s u r e c o e f f i c i e n t .

? a Bihour ly v a l u e s f o r p r e s s u r e .

P a Monthly mean v a l u e s of p r e s s u r e , v^ ich

i s 39*7 iBb. i n t h i s e a s e .

( i ) g^SSOAii; OUiiEilQailQH J -

froai t a b l e 57 and 58 t h e v a l u e s of I^ .and

( 1 - f ) , f o r t h e f i r s t day and 0000 h o u r s , a r e 6 5 7 . 5

and +2 .4 r e s p e c t i v e l y . S u b s t i t u t i n g t h e above v a l u e s

l a ( A . l ) , we g e t

• 657 .5 - 1 . 1 8 ( 2 . 4 ) P I p « 657 .5 - 2 .85 « 654.67

o r 1 ^ ^ 6 5 4 , 7 count a / b i - h o u r .

t he p r e s s u r e c o r r e c t e d va lue f o r t h e f i r s t

day and 0000 h r . eomes ou t t o be = 654*7 O o i m t s / b l - h o u r .

Data i s c o r r e c t e d f o r each d a / and each b i h o u r . Thoee

r e s m l t s a re presteated i n f a b l e 36.

I r o a t h i s p r e s s u r e o o r r e c t e d d a t a , g iven i n

f a b l e 36, t n e 1 2 - b i h o u r l y average v a l u e s a r e o b t a i n e d

by a v e r a g i n g the 12 v e r t i c a l columns, f h e s e v a l u e s

a r e g iven a t t h e bottom of Sable 36 . 0 s i n g t h e s e

1 2 - b i - h o u r l y v a l u e s the d a t a f o r t h i s month can be

harmojaical ly ana lysed to ge t t h e f i r s t and second

harmonic components of t h e d a i l y v a r i a t i o n of meson

i n t e n s i t y . The method i s d i s c u s s e d below i -

( i i ) aAEMOaiQ AliU iYSIS s -

f a b l e 39, g i v e s t h e s imple r method of

harmonic a n i ^ y s i s i n t h e Tabular fo rm, u^ , u ^ , Ug ,

. . . . . . . . u ^ ^ a r e t h e 1 2 - b i h o u r l y v a l u e s , f h e a c t u a l

v a l u e s of , ^ ^ ^ ^ ^ fJtom f a b l e 36 ,

a r e s u b s t i t u t e d i n Table 39 a t t h e i r p rope r p l a c e s

a s shown i n t a b l e 40.

f h a s from f a b l e 40 , t h e affl-plitude and phase

o f t h e f i r s t hax^moaic component f o r Ifov. 1958, comes

o u t t o be and 11^ r e s p e c t i v e l y . S i m i l a r l y one

eaa gfet ti ie ampl i tude and phase of t h e second haraoiaic

compoaerit a l so f r o a t k i s t a b l e 40 .

iri!

vo ers t I

m H *

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APgMDIX

A e t a a l i y e r a p t i o n s on t h e chromosphere of

t h e sun a r e termed a s «Sola r f l a r e s « . A s o l a r

f l a r e i s a r e g i o n i n t h e chroaosphere hav ing p r o -

j e c t e d a r e a of a few hundred m i l l i o n t h s of t h e

v i s i b l e diak, of the aim, whieh e m i t s i i^^ht i n t h e

Hydrogen and a t l i e r p a r t s of t h e spectruia s d t h

g r e a t e r i n t e n s i t y t h a n the con t inuous background

of t h e s o l a r d i s k , f l a r e s u s u a l l y s t a r t sudden ly ,

r e a c h maximuffi i n t e n s i t y i n a few si inutes» and

d i s a p p e a r w i t h i n an h o u r , f h e r e p o r t s on f l a r e s

normal ly g i v e t imes of beg inn ing , maximiaffl and t h e

end of f l a r e , t h e p o s i t i o n , t h e i n t e n s i t y of Hoc

l i n e , width of H l i n e and t h e • importance* e t c .

f h e r ^ a t i n g of the ' i a ipor tance* of the f l a r e s

i s done on t h e s c a l e 1 , 2, 3 and i s a somewhat s a b -

j e e t i v e measure , f h e imj>ortance g i v e n t o t h e f l a r e s

i s merely based on t h e a r e a and t h e i n t e n s i t y of the

f l a r e . H a r e s oove r i ag m a r e a up to 250 m i l l i o n t h s

of t h e s o l s r d i s k a re r a t e d of impor tance I j t hose

hav ing s r e a 250 t o 600 m i l l i o n t h s a r e c l a s s e d i n 2}

whi le t h o s e wi th a r e a above 600 m i l l i o n t h s a r e c l a s s e d

a s 3 . However, t h e s e l i i a i t s a r e not r i g i d ; they can. be

a d j u s t e d i f t h e f l a r e i s e x c e p t i o n a l l y b r i ^ t o r weak

f o r i t s a r e a , and some t imes -tt or - s i g n s a r e addid t o t h e impor tance r a t i n g ( s e e Table 4 . 1 ) . f h u s t h e impor tance o f t h e J t lare I n d i c a t e s i t s s i z e and t h e i n t e n s i t y .

» a}

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152

Llat of a a s l l s o l a r f l a r e s f o r t h e perloQ Jajiiasi^ t o August, 1058,

froffi

Month Bate t Beginning ' h r e . ( U . f . )

I n p o r t a n c e . 1

tianuary 1 9 6 8 , , , « 2 0557

15 0009 16 09g? 1 2S 0520 1 84 0334 1 g6 2

Febrimfy 1 9 5 8 . , . . 4 0539 1

4 0901 1 11 0252 1 11 0532 1 12 0937 1 13 0144 1 E5 0i5S 86 0449 1 28 0438 1

Harch 1 9 5 8 . , , 8 1060 - —

10 0210 IS 0344 14 0442 17 0438 17 10^ 1 2 1 1040 22 0S41 23 1016 a 2S 0257 1 25 0529 2 2§ 0557 2

Cont d . • .

153

- (11) -

Month 1 Date Beginning ^ ' h re* {U.T.)

Ifflportanoe.

March 1958 27 1 31 0856 1 3 i 1025^ 1"

A p r i l 1 9 6 8 . . 1 Olii5 1 2 1 2 0502 2 3 I 7 l o g a 8 8 Q^Oh. 1

16 0535 1" 28 105S r

May 1 9 5 8 , . . « 1 xom r 2 0646 1 5 G407 1+ 8 054'9 1

30 0326

^ime 1958,.,. 6 0520 5 0800 6 0438 6 0458 2

10 0307 1 10 0602 1 11 0552 1 11 6231 14 0630 1 18 0319 1 18 0538 1 19 0456 i l 19 10C3B 19 0212 2 S6 0300

Ju ly 1 9 5 S . . . ^ O3O? 26 0205 1

Ll^gr OF PUBLIGATIOHS

1, '"CGSiuic-Ray I n c r e a s e Associa ted W|fch A isiaall i^olar F la re" I n d . J , Meteorology and Geophysics, Vo l . I I , Ko,2, 169Xia5®)

'•LATITTOS DEPSNDENGE OF AMPLITUDE AND PHASE OF THE ®UR»Afl VARIATIOH" Nat,Acad.i3c(.,In<^a, V o l . 3 3 , Sec.A, psiM 2 , ' 213 (1963)

3 . "DITJRML VARIATION OF CObMIC RAY INTSNblTY AT GULMARG ( X=24.7 I?)" Nat . Acad. Set I n d i a , V o l . 3 4 , bec.A, p a r t I 53 (1964)

4. " R E U T I f H ^ P BJITWEEN THE SOLAR kW MAGNETIC PHEMOMEHA WITS COa!IC BAY INTENSITY" Ha t . Acad. ScC I n d i a , Vol34f, Sec .A p a r t 4 , 561 (13S4) .

5 . "EXPSMMSITAL ARRAMGEMSHT OF M2S0N CUBICAL TELESCOPE AS WELL AS NARROW ASGLB TELESCOPES" i s p re sen ted i n the cosmic-r ay syraposiua h e l d a t Bcsnbay i n 1959.

ir.amu.ac.inir.amu.ac.in/618/1/t 634.pdfill agkholepgemeht %lille sal^ittija thi thesigs ths authoe...

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