1. Dynamics of reconnection and multiple activation of substorms
2008/02/26 Rumi Nakamura (IWF/OEAW)
Study X-line signatures and examine their relationship to substorm development
-Current sheet observations
Jan. 09, ~ 700 UT event
Feb.16, ~ 220 UT event
-Remote sensing
Feb.10, UT, 545 UT event

2. Major conjunction
~0700UT AE ~400 nT
With multiple activations

3. Thinning CS Tailward evolution of X-line
THB: lobe  PSBLPS 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: UT THE  THD
II: 722 UT THD, THE
Thinning CS
Dipolarization I II

4. DATA QUESTION? For reconnection current sheet,
Determine flow reversal is useful
DATA QUESTION?
How far can we use ESA,SST
moments. Looks SST portion important. What should we do ?

5. BBF-like signatures observed at D and E with differences
(interesting to compare for these two different activations)
DATA QUESTION?
SST moment is important!?
THD
THE

6. UT 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.

7. centered high-lat. (Rank) or Greenland(?, tbd)
Minor conjunction
0220 UT - AE ~250 nT

8. Two X-line activations rather than in-site Xline observation?
Bz reversal around II
Two X-line activations rather than in-site Xline observation?
THC: PSBLPS I: negative Bz tailward of Xline
II: postive Bz
earthward of X line
THD, THE : dipolarization
I: ~220 UT
II:~0244 UT
Dipolarization I II

9. DATA QUESTION? For studying reconnection current sheet, determine flow
reversal timing is very important
DATA QUESTION?
Similar to event,
SST seems to show reversal...
How far can we use ESA,SST
Moments? Recommendation ?
Like event
THEMIS D and E have also
similar issue

10. Similar to 20080109 event BBF-like signatures observed at D and E with differences
(interesting to compare for these two different activations)
DATA QUESTION?
SST moment is important!?

11. UT 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.

12. Two small activations centered high-lat. (Rank) or Greenland(?, tbd)
Major conjunction
0430UT AE ~200 nT
0540UT AE ~350 nT

13. Remote X-line sensing between C and B
THB: Tail lobe Bz +  -
THC: lobe/PSBL
Bz -  flux rope, 2 TCR
D, E: expansion of plasma sheet

14. THB
Relationship between earthward motion of flux rope and innermagnetospheric signatures could be studied
THD
DATA QUESTION?
Is this taiward flow OK ?
THE
The spectra around
UT may look dark region at two place?
(multi composition ?)

15. Tailward motion or two of very weak TCR ?
THB: lobe Bx - , Bz -
THC: lobe
Bx + , Bz -

16. 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...