dynamics of reconnection and multiple activation of substorms
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Dynamics of reconnection and multiple activation of substorms
Study X-line signatures and examine their relationship to substorm development
-Current sheet observations• Jan. 09, 2008 ~ 700 UT event• Feb.16, 2008 ~ 220 UT event
-Remote sensing• Feb.10, 2008 425UT, 545 UT event
2008/02/26 Rumi Nakamura (IWF/OEAW)
Major conjunction~0700UT AE ~400 nTWith multiple activations
Thinning CSTHB: lobe PSBLPS I: BY increase II: Bz - Bz +
THC: PSBL lobe PS I: BY increase, Bx decrease short dBz>0 while Bz decrease II: Bz - +
THD, THE: two dipolarizations I: 654 UT THE THD II: 722 UT THD, THE
Tailward evolution of X-line
Dipolarization I II
DATA QUESTION?
For reconnection current sheet,Determine flow reversal is useful
How far can we use ESA,SSTmoments. Looks SST portionimportant. What should we do ?
DATA QUESTION?
BBF-like signatures observed at D and E with differences(interesting to compare for these two different activations)
THD THE
SST moment is important!?
20080109 07UT event summary• Modest substorm with multiple activations
(AE 400 nT) • Bz reversal (flow reversal?) observed by B and C
with time difference motion/evolution of Xline. • Two dipolarizations observed by D-E
I. during current sheet thinning at C and B
II. associated with X-line at C (and B)
Plan: Confirm X-line signatures with particle/field data, compare flow evolution for I. II.
centered high-lat. (Rank) or Greenland(?, tbd)
Minor conjunction0220 UT - AE ~250 nT
Dipolarization I II
THC: PSBLPS I: negative Bz tailward of Xline II: postive Bz earthward of X line
THD, THE : dipolarizationI: ~220 UTII:~0244 UT
Bz reversal around IITwo X-line activations rather than in-site Xline observation?
DATA QUESTION?
For studying reconnection current sheet, determine flow reversal timing is very important
Similar to 20080109 event,SST seems to show reversal...How far can we use ESA,SSTMoments?Recommendation ?
Like 20080109 eventTHEMIS D and E have alsosimilar issue
DATA QUESTION?Similar to 20080109 eventBBF-like signatures observed at D and E with differences(interesting to compare for these two different activations)
SST moment is important!?
20080216 0220UT event summary• Small activation (high-lat.) (AE ~250 nT) • +Bz and –Bz enhancement (or Bz reversal)
observed by C associated with two dipolarization event (D, E) and ground-based activation. Different activation of X-line(s?) at different location (first Earthward then tailward side of C)
• Plan: Confirm X-line signatures with particle/field data (Timing of flow reversal essential) Compare flow evolution for I. II.
Two small activationscentered high-lat. (Rank) or Greenland(?, tbd)
Major conjunction0430UT AE ~200 nT0540UT AE ~350 nT
THB: Tail lobe Bz + -
THC: lobe/PSBL Bz - + 1 flux rope, 2 TCR
D, E: expansion of plasma sheet
Remote X-line sensing between C and B
DATA QUESTION?
THB
THD
THE
Relationship between earthward motion of flux ropeand innermagnetospheric signatures could be studied
Is this taiward flow OK ?
The spectra around0552-55 UT may look dark region at two place?(multi composition ?)
Tailward motion or two of very weak TCR ?
THB: lobe Bx - , Bz - THC: lobe Bx + , Bz -
20080210 0430-0550 UT event summary
• Two modest activations (200, 350 nT) • Lobe/PSBL signatures may allow to remote-
sensing the X-line• Plan: Using transient reconnection model
(Semenov et al., 2007) to model location/motion of X line, temporal change of reconnection rate (by Stefan Kiehas)
• .. We are still on search of this kind of event...
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