cosmic rays in the solar environment

COSMIC RAYS IN

THE SOLAR ENVIRONMENT

José Fco. Valdés-GaliciaDepartamento de Investigaciones Solares y Planetarias

Instituto de Geofísica

Universidad Nacional Autónoma de México

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THE HELIOSPHERE

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A Bird´s eye view of the Solar Interior

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The Sun, our star

Surf ace temperature 5800 KRotation duration 27.25 days (synodic), at equator,

25.38 days (sideric), at equator.Age 4.60 billion yearsNumber of planets 9, plus many tiny onesNext neighbor star Alpha-Centauri, at 4.37 lightyearsNext neighbor galaxy Magellan’s Clouds, at 165,000 lightyearsEarth’s distance variation +/ - 1.69 % (+ in J uly, - in J anuary)

Apparent diameter 31’ 59.3” = 1913.3 “ i.e. 0.5 degreeApparent radius 959.65” i.e. 1000 arcsec1 arcsec on sun, f rom Earth 725 kmEnergy output 3.82 x 1033 WattEnergy input into Earth 1,370 Watt/ m-2

total 173 Mio Gigawatt

Name SunParent galaxy Milky WayType fi xed starSpectral class G2Magnitude + 4.8Distance to Earth 149,598,000 km i.e., 1 AU Radius Rs 696,000 km i.e., 109 RETotal mass Ms 1.989 x 1030 kg i.e., 333.000 MEDensity (average) 1.409 g cm-3

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SUNSPOTS

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SOLAR TOTAL IRRADIANCE

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Solar maximum

Solar minimum

Xray images

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1973

1980

1991

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THE SOLAR CORONA

It must be very hot otherwise it wouldn´t be so extended

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SOLAR ATMOSPHERE TEMPERATURES

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16The corona of sun at beginning activity (1998), viewed by EIT and LASCO- C1/C2

The two states of corona and solar wind

Coronal holesproduce the„f ast wind“

Active regions and streamers let the „slow wind“ emerge

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Perihel passage

IMP 8

Solar wind speedkm/s

Heliographiclatitude

Heliographic longitude

Solar wind stream structure, seen nearly simultaneously f rom 1 AU and f rom 0.3 AU (IMPand Helios 1) in early 1975, associated with coronal hole

structure. Note that Helios passed the northern boundary of the f ast stream, while I MP at low latitude did not.

(Earth)

Latitudinal stream boundaries

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THE “BALLERINA SKIRT”

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The „ballerina skirt“ trough the solar cycle

During maximum the “ballerina skirt” reverses polarity for the next minimum. The magnetic cycle of the Sun (Hale) takes 22 years.

Minimum

Minimum

Maximum

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THE HELIOSPRERE IN 3-D

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THE END OF THE HELIOSPHERE

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Fermilab

LHC CERN

1part per Km2-century

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THE HELIOSPHERE

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• f(r, E, t). CR distribution function– r = position; E = Energy; t= time

• a) Convection and magnetic drift due to gradient and curvatureof HMF

• b) Adiabatic cooling

• c) Diffusion (HMF irregularities)

• d) Additional sources (acc at Terminal Shock)

0)(3

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d

Qc

f

b

fEE

a

ft

fsSD

κVvV

COSMIC RAY TRANSPORT IN THE HELIOSPHERE(FOKKER-PLANCK)

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Potgieter & Ferreira(2004)

(Valdés-Galicia et al., 2005)

• (K , K ) from numerical•simulations

•Boundary at 90 AU

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Flares and Coronal Mass Ejections

„Bastille day“ flare July 14, 2000

15 Ene, 1996, LASCO-C3 en SOHO

• Flares are short duration solar explosions that emit in: visible, UV, XRays, rays, energetic particles.

• CMEs are expulsions of great ammount of plasma generating shock waves.

• Flares and CMEs are quasi-simultaneous.

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31Masuda et al. 1994

Solar Flare model

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ENERGETIC PROTONS→ NUCLEAR REACTIONS IN FLARES

Evidence:

Positron anihilatione+, e- (0.511MeV)

Neutron capture lines1H(n,)2H (2.223 MeV)

Gamma ray lines (nuclear deexitation)160(6.129 MeV) 12C(4.438MeV)

Gamma rays from o , ± decay(peak o at 70 MeV)

protons and electrons transport is governed by electromagnetic fields in the Sun and interplanetary medium.

Neutrons Do Not→ they preserve information from the acceleration site.

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Solar Neutron Telescope World Network

34EVENT ON 7 SEPTEMBER 2005

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SUMMARY

• GCR with E 1011 eV are modulated by the solar activity (anticorrelation)

• GCR intensity has cycles of 11y (activity) and 22y (magnetic)

• Solar modulation of GCR results from an interplay of:

– DRIFT GRADIENT AND CURVATURE OF HMF– DIFFUSION MAGNETIC TURBULENCE– CONVECTION TURBULENCE IS CARRIED BY SOLAR WIND– ADIABATIC DECELERATION SOLAR WIND EXPANSION

• Besides electromagnetic radiation, the Sun emmits energetic particles (p´s, e´s, ´s, n´s).

• Solar Neutrons preserve information of the acceleration site.

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CALL FOR PAPERS

January 2007