Pseudo-breakups and substorm observed by THEMIS on January 29, 2008: timing analysis Many thanks to E. Penou (CESR) and T. Moreau (GFI) for developing data interface with the CL software T meeting, UCLA, April 9-11, 2008 Jacquey C., O. LeContel, A. Tallet, V. Génot , P. Louarn, G. Fruit, B. Lavraud, J.A. Sauvaud, A. Roux, V. Angelopoulos, D. Sibeck, J.P. McFadden, D. Larson, U. Auster, H. Singer
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Pseudo-breakups and substorm observed by THEMIS on January 29, 2008 : timing analysis
Pseudo-breakups and substorm observed by THEMIS on January 29, 2008 : timing analysis. Jacquey C., O. LeContel, A. Tallet, V. Génot , P. Louarn, G. Fruit, B. Lavraud, J.A. Sauvaud, A. Roux, V. Angelopoulos, D. Sibeck, J.P. McFadden, D. Larson, U. Auster, H. Singer. - PowerPoint PPT Presentation
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Pseudo-breakups and substorm observed by THEMIS on January 29, 2008: timing analysis
Many thanks to E. Penou (CESR) and T. Moreau (GFI) for developing data interface with the CL software
SWT meeting, UCLA, April 9-11, 2008
Jacquey C., O. LeContel, A. Tallet, V. Génot , P. Louarn, G. Fruit, B. Lavraud, J.A. Sauvaud, A. Roux, V. Angelopoulos, D. Sibeck, J.P. McFadden, D. Larson, U. Auster, H. Singer
BC
DEG12
Mid-tail Near-Earthtail
G12
D
C
E
GTL
CL
21 22 23 00 01 02 030
10
20
30
40
MLT (HOURS)
L (R
e)
January 29, 2008, 02:45 UT
G12E D
C
B
Large scale features
No important change of SW velocity and pressure during the 01:00-03:00 UT period
Ground-North America/MLT:21-17
Dipolarisaiton, ~02:57
GOES-12BZ-GSM
Global energy assessment
4 successive events: 2 pseudo-breakups1 substorm including 2 intensifications
0
0.1
0.2
Ps: black Pm: green Pthi(ESA): blue Pthi(SST): red
Earthward/tailward propagation of the dipolarisations
0.220.240.260.280.3
0.32
January 29, 2008
PsC
(nP
a)
-1
0
1
BzC
(nT
)
0.16
0.18
PsB
(nP
a)
-2
-1
BzB
(nT
)
02:45 02:48 02:51 02:54 02:57 03:00
3
4
5
XP
s/<
Ps>
(%
)
January 29, 2008: preliminary conclusions
For all events:-In the near-Earth tail, the dipolarisation, magnetic turbulence and energetic ion flux enhancements propagates earthward (large scale trend)-Low frequency (2-3 minutes) flow oscillations observed in near-Earth tail-The global development of the dissipation events seem to progress by steps, via successive local and discrete intensifications (Lopez et al., 1993)
Pseudo-breakups:-Small plasmoids observed first in the mid-tail, before the energetic ion enhancements and dipolarisation in the near-Earth tail Main substorm:-Energetic ion enhancements and dipolarisation are observed first in the near-Earth tail the current disruption is likely the cause of the global energy dissipation- The magnetic signatures in the mid-tail are consistent with a tailward propagating cross-tail current disruption.
0.220.240.260.280.3
0.32
January 29, 2008
PsC
(nP
a)
-1
0
1
BzC
(nT
)
0.16
0.17
0.18
0.19
PsB
(nP
a)
-2.5
-2
-1.5
-1
BzB
(nT
)
02:45 02:48 02:51 02:54 02:57 03:00
3
4
5
XP
s/<
Ps>
(%
)
90°270°
Earthward initial locationR < 10 Re
Passing through the S/C
Assuming DSL ~GSE
90°270°
Earthward initial locationR < 10 Re
Not passing through the s/c
90°270°
Tailward initial locationR < 10 Re
ACE GTL
WIND
IMF:~2 hour southward IMF period
Northward turning at ~03:00 UT on GEOTAIL
Neutral line modelCurrent disruption model
02:15 02:20 02:25 02:300.3
0.32
0.34
Ps
(nP
a)January 29, 2008
B (T = -185 s)
C
02:15 02:20 02:25 02:30-4
-2
0
2
4
BZ
(nT
)
B (T = -195 s)
C
0 0.05 0.1 0.15 0.2 0.25 0.3 0.350
0.05
0.1
0.15
0.2
0.25
0.3
0.35TH-C 01:00-02:30
Pm
(nP
a)
Pthi[ESA+SST] (nPa)
Pm = -0.73 Pthi + 0.26
0
0.1
0.2
Ps: black Pm: green Pthi(ESA): blue Pthi(SST): red
B (
P1)
0
0.2
0.4
C (
P2)
0
0.5
1
D (
P3)
01:00 01:45 02:30 03:15 04:00 04:450
0.5
1
1.5E
(P
4)
Ps_C computed with corrected PthiCorrection coefficient: K = 1.37
K = 1/0.73 = 1.37
Energetic ion anisotropy analysis
90°270°
B
X
Y
Z
090
180270
time
090
180270
time
090
180270
time
Source located tailward
Source located earthward
passing from earthward to tailward
Ev1: earthward > tailward Local tailward propagation?Ev2: source located earthward of the S/C, the front does not pass through the S/CEv3: tailward > earthward Local earthward propagation?