themis summary data plots
DESCRIPTION
A. B. C. THEMIS Summary Data Plots. D. E. Major Conjunction. G12. D. C. B. E. A. G11. Outside-in spreading: B => C => D/E => A Inside-out spreading: A => D/E => C => B. Left: positions of five Themis and two GOES satellites for 2008 Jan 29 0700-0900 UT interval. - PowerPoint PPT PresentationTRANSCRIPT
THEMIS Summary Data PlotsA B C
D E
XGSM
YGSM
20 RE
30 RE
–30 RE
–30 RE
A B C D E GOES11 GOES12
2008 Jan 29 0700 - 0900 UT
Left: positions of five Themis and two GOES satellites for 2008 Jan 29 0700-0900 UT interval.
Right: AU/AL indices for the interval. Objective: Examine time history of events (inside-out/outside-in?)
Outside-in spreading: B => C => D/E => AInside-out spreading: A => D/E => C => B
-200
-100
0
100
07:00 07:30 08:00 08:30 09:00
AL AU
2008 January 29
0714 0740
0834
BCD
EAG11
G12
Major Conjunction
Fort Smith (FSMI) Jan 29, 2008
07:00 07:15 07:30 07:45 08:00 08:15 08:30 08:45 09:00
THEMIS GBO FSMI Keogram on 2008 January 29
Arc brightening with subsequent poleward expansion
Poleward arc undisturbed
Poleward arc undisturbed
07:00 07:15 07:30 07:45 08:00 08:15 08:30 08:45 09:00
THEMIS GBO FSIM Keogram on 2008 January 29
Arc brightenings with subsequent poleward expansion.For first and second auroral activation, arc poleward of initial brightening remained undisturbed until poleward expansion reached there.For the third auroral activation, the initial brightening arc is most poleward arc.
THEMIS Vix and Bz ~0714 UT
20
10
-4
-2
0
5
0
-5
15
10
5
020
10
007:00 07:30 08:00 08:30 09:00
2008 Jan 29 THEMIS/MGF Bz
At ~0714 UT, temporal sequence: D/E => B
200
0
200
100
0
-100600
400
200
0
-200
500
0
200
0
-200
07:00 07:30 08:00 08:30 09:00
2008 Jan 29 THEMIS/ESA Vix
THEMIS Vix and Bz ~0735 UT
20
10
-4
-2
0
5
0
-5
15
10
5
020
10
007:00 07:30 08:00 08:30 09:00
2008 Jan 29 THEMIS/MGF Bz
At ~0735 UT, temporal sequence: A => D/E => C
200
0
200
100
0
-100600
400
200
0
-200
500
0
200
0
-200
07:00 07:30 08:00 08:30 09:00
2008 Jan 29 THEMIS/ESA Vix
THEMIS Vix and Bz ~0835 UT
20
10
-4
-2
0
5
0
-5
15
10
5
020
10
007:00 07:30 08:00 08:30 09:00
2008 Jan 29 THEMIS/MGF Bz
At ~0835 UT, temporal sequence: C => E => D => A
200
0
200
100
0
-100600
400
200
0
-200
500
0
200
0
-200
07:00 07:30 08:00 08:30 09:00
2008 Jan 29 THEMIS/ESA Vix
30
20
10
0
2
3
4
567
10-2
2
3
4
567
10-1
2
3
4
07:45 07:46 07:47 07:48 07:49 07:50
0.3
0.2
0.1
0.0
2008 Jan 29 THEMIS A/FGM
UTXgsm (R E)Ygsm (R E)Zgsm (R E)
-8.3 1.3 -2.7
-8.3 1.2 -2.8
nT
Summary• Three auroral activations occurred during a major tail
conjunction.
• First activation is an isolated substorm with time history consistent with an inside-out scenario; it does not involve mangetic reconnection of open magnetic field lines.
• Second activation is a moderate size substorm with an inside-out time history.
• Third activation is an intensification of the substorm started with the second activation. Its time history is consistent with outside-in scenario.
• Second and third auroral activations are different episodes of a weak substorm consistent with the substorm synthesis model.
• Wavelet analysis suggests that dipolarization originates from waves excited at ~7-30s period.