THEMIS SWT, UCLA, April 9-11, 2008 1

THEMIS GBO/ASI

Minor intensificationGBAY 01:48:42 KUUJ 01:48:51 CHBG 01:49:39 SNKQ 01:50:54 GILL 01:51:18 TPAS 01:51:21

Major intensification (substorm)GBAY 01:55:36 KUUJ 01:55:21 CHBG 01:56:33 SNKQ 01:52:27 GILL 01:54:21 TPAS 01:54:30

THEMIS SWT, UCLA, April 9-11, 2008 2

THEMIS SC, GBO and GOES observations 08-03-01/0100 – 0210 UT

P1

P2P3

P4

G10G12

01:48:50 UT

GBAY

KUUJ

0148:42 0154:21

THEMIS SWT, UCLA, April 9-11, 2008 3

P1 and P2: X=-22.7, -17.4 RE

THEMIS SWT, UCLA, April 9-11, 2008 4

P2P1

THEMIS SWT, UCLA, April 9-11, 2008 5

Timing of HE particles (P1 and P2 SST)First tailward burst

0148:42 UT 0148:42 UT

134 keV

P2P1

THEMIS SWT, UCLA, April 9-11, 2008 6

THEMIS SWT, UCLA, April 9-11, 2008 7

P3 and P4: X=-9.5, -8.0 RE

THEMIS SWT, UCLA, April 9-11, 2008 8

Magnetic field variations at P3, P4,GOES 10, GOES 12

P3 and P4 FGM measurements:

Total field (Bt) at P3 and P4 continuously increases until ~0955 UT

Variations of the components, (baseline subtracted):

• δBy and δBz started at 0148:20 – 0148:40 UT, indicating outward FAC underneath the SC, while Bx and Bt were increasing (the total current built up) until ~0154:30UT (current reduction/disruption).

• CR/CD P4 P3: Tailward at a velocity of 150 km/s

GOES 10: Positive δBn (eastward!) at 0148-

0155 UT G10 was under the FAC

GOES10, 12: Dipolarization started at ~0155 UT

THEMIS SWT, UCLA, April 9-11, 2008 9

2008-03-01/0140 – 0205 UT

First activation0148:20: HE electron flux increase at P20148:20: ~150 keV ion flux increase at P20148:30: minor δBy at P3 & P40148:42: Auroral onset at GBAY0148:45: PI2 onset at GBAY0148:50: δBy and δBz at P2/THC0148:50: Tailward flow at P2/THC0149:30: δBy and δBz at P1/THB0149:30: Tailward flow at P1/THB0149:30: major δBy δBz at P3 & P4

Second activation (substorm)0154:21: Auroral onset at KUUJ0154:30: Tailward flow at P10154:30: δBy, δBz at P20155:00: Tailward flow at P20155:00: Drop of Bt at P40155:00: Dipolarization at P40155:00: δVy, δVz at P40155:50: Drop of Bt at P30155:50: Dipolarization at P30155:50: δVy znd δVz at P3

Signatures in space and in the ionosphere are seen within 20 s!

Current reduction /CD at X~-8 RE and plasma acceleration at X~-17 RE acted almost simultaneously (independently?)

THEMIS SWT, UCLA, April 9-11, 2008 10

THEMIS SWT, UCLA, April 9-11, 2008 11

THEMIS ASI

GBAY

P1

P2P3

P4

G10G12

3 variants of mapping: TIPSOD (T96?), T96 SW, Event Oriented (EO)

T96 SW

EOTIPSOD