euv observations of the structure and dynamics of the plasmasphere bill r. sandel, jerry goldstein,...

EUV Observations of the Structure and Dynamics

of the Plasmasphere

Bill R. Sandel, Jerry Goldstein, Dennis Gallagher, & Don Carpenter

The Plan

EUV Measurements

Trough Formation

Plasmasphere Erosion

Bite-Outs (Low Density Regions)

Flux Tube Refilling

The scattering rate or “g-value”:

g = ~1.1 10-4 sec-1

for He+ at 1 AU

S unlight at30.4 nm

Scatte

r ing in a ll directions

The light detected by EUV comes from

Resonant Scattering

Surface Brightness of the Plasmasphere

The surface brightness is a line integral along the line of sight for each pixel:

Mapping image field points to the equatorial plane

To Sun

Earth’s Shadow

Aurora

Imperfect Flat-Fielding Between Cameras

Plasma Tail

Plasmapause Plasmasphere

Extended Plasmasphere

Small Plasmasphere

(Thanks to Mark Moldwin)

Trough Forms by Wrapping a Tail

9 May 2001

2001-129

Plasmasphere Erosion Events 10 July 2000

Distance, Content vs. Time

Plasmasphere Erosion Events 2 June 2001

Bite-Outs in the Plasmasphere

CRRES Results

Carpenter et al., JGR 105, 23,323 (2000)

Green et al., JGR in press

2001-097 & 098

(7 & 8 April)

87% CoR

2000-187 to 189

(5-7 July)

84% CoR

2000-176 to 177

(24-25 June)

98% CoR

Same as inner cavities observed by e.g. CRRES?

CRESS* EUV

Frequency 13% less frequent

Contrast 5-10x 2-4x

Azimuthal Extent up to 20° 10-18°

Inner Boundary L < 3 ~same

LT Distribution < morning ?

*Carpenter et al., JGR, 2000

2000-176

2001-097

Real Modelled

90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185

Dst

(nT

)

-120

-100

-80

-60

-40

-20

0

20

40

60

80

180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275

Dst

(nT

)

-120

-100

-80

-60

-40

-20

0

20

40

60

80

Time (Days of 2000)

270 275 280 285 290 295 300 305 310 315 320 325 330 335 340 345 350 355 360 365

Dst

(nT

)

-120

-100

-80

-60

-40

-20

0

20

40

60

80

dst2000.jnb

90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185

Dst

(nT

)

-120

-100

-80

-60

-40

-20

0

20

40

60

80

Time (Days of 2001)

180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275

Dst

(nT

)

-120

-100

-80

-60

-40

-20

0

20

40

60

80

90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185

Kp

0

2

4

6

8

10

Time (Days of 2001)

180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275

Kp

0

2

4

6

8

10

90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 175 180 185

Kp

0

2

4

6

8

10

Time (Days of 2001)

180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 265 270 275

Kp

0

2

4

6

8

10

from Wilson et al., Adv. Space Res., 1993.

Flux Tube Refilling--Expectations

Latitude (degrees)

H+ D

en

sity

(cm

-3)

26 August 2000

Isolated Refilling Flux Tube

20 August 2000 08:26 UTC

Model of an Isolated Filled Flux Tube

Range 7.9 RE

Latitude 49 N

?