1. THEMIS First Results and near future
Introduction, THEMIS overview
First THEMIS results from the tail
THEMIS results in other regions
Data availability
Future activities

2. THEMIS Mission elements
Probe conjunctions along Sun-Earth line recur once per 4 days over North America.
Ground based observatories completely cover North American sector; determine auroral breakup within 1-3s …
… while THEMIS’s space-based probes determine onset of Current Disruption and Reconnection each within <10s.
: Ground Based Observatory

3. Near-Earth tail reconnection Localization: the case for “point” reconnection
Angelopoulos et al., 1998 (Case study on localization)
Nakamura et al., 2004 (Cluster statistics on localization)
Scales: Vertical: RE, Azimuthal: 2-3 RE Sharper gradient on duskside flank

4. Nagai 1991 results
T = x MLT** x MLT** x MLT** x MLT
T delay time (minutes) at each MLT
Here, 23 MLT is -1.0, 22 MLT is -2.0
24 MLT min (not well bound by data, a statistical average)
23:32MLT min (the center of the current wedge, average)
23 MLT min (not well bound by data, a statistical average)
22 MLT min
21 MLT min
20 MLT min

5. The 3D nature of the Rx process
0204UT
JGR [Angelopoulos et al, 1995]
Substorm Onset: ~0202UT
Ygsm
Xgsm
0215UT
Ygsm

6. Mission overview D2925-10 @ CCAS BGS Release Operations UCB
SST
ESA
EFIa
EFIs
FGM
SCM
Tspin=3s
BGS
CCAS
Release
Operations
UCB
Encapsulation
& launch
Probe instruments:
ESA: ElectroStatic Analyzer (coIs: Carlson and McFadden) SST: Solid State Telescopes (coI: Larson) FGM: FluxGate Magnetometer (coIs: Glassmeier, Auster & Baumjohann) SCM: SearchCoil Magnetometer (coI: Roux)
EFI: Electric Field Instrument (coI: Bonnell)
Mission I&T
UCB
Ground
Instrument I&T
UCB

7. First light: Nature’s welcome. Two substorms seen on March 23
DETAILED VIEW
THEMIS
TH-E
THE Y Y
TH-A Z
TH-B
TH-D X
THEMIS glimpsed the tail in the middle of its commissioning phase, before moving towards the dusk sector.
In an orbit designed to simulate routine science operations, it captured two substorms from a good vantage point.
The THEMIS probes were arrayed like pearls on a string with end-to-end separation of 10Re.
The middle probes (A, B, and D) were separated by ~ 0.25Re.
In addition, the POLAR spacecraft was imaging the southern auroral oval.
TH-C
SUN
THA X
THB
THC Z
THD
SUN
POLAR

9. Courtesy: Parks and Fillingim
From UVI
Courtesy: Parks and Fillingim
At 11:18:26UT.
Substorm 23MLT
By 11:19:40UT.
Auroras expand to 21.5MLT
By 11:23:21UT
Not much further expansion
Consistent with VIS due to 0.5MLT UVI uncertainty from POLAR wobble

10. From VIS: 2007_082_1008-1309_all.mov At 11:18:03-45UT. By 11:19:57UT.
Auroras 23MLT
By 11:19:57UT.
Auroras expand to 22MLT
By 11:23:21UT
No further westward expansion observed

11. Keograms from UVI

12. At 11:18:42UT. From: 3_23_07_mosaic.mov
Onset at 23MLT (see Mende et al.)

13. Apatenkov/Sergeev model: SCW Upward FAC jumps to 21
Apatenkov/Sergeev model: SCW Upward FAC jumps to 21.5MLT and stays there for >20 minutes

14. Classical mapping
Tsyganenko 2001 mapping: THEMIS maps to 21.5 MLT (other models, or higher activity place thm to the West).
21.5MLT

15. Courtesy: J. Raeder (UNH)
Simulation mapping
OpenGGCM mapping: THEMIS just before simulation
onset maps to ~22.5 MLT, i.e., right in the middle of expanding activation. Note: mapping evolves
Courtesy: J. Raeder (UNH)

16. X Z Y B
FAC By B sc
Assuming an outward plasma sheet expansion (evidenced by the |Bx|
reduction - interpreted as a diamagnetic effect) the FAC is a pair of
oppositely directed current sheets, embeded in an overall outward current sheet. This is consistent with THEMIS being at the westward edge of the WTS.

17. Moments
Overview
TH-D

19. Courtesy: L. Kepko (UNH)
Vorticity in FAC coordinates
From TH-D,B,A (inner)
Check using different center probe
From DBA, BAD, ABD
Courtesy: L. Kepko (UNH)

20. Strangeway et al. SM11A observe similar signatures of FAST

21. Conclusions, March 23 event:
Measured expansion is much faster than previously measured locally but agrees with expectations from statistical averages First time it has been observed by nearby satellites.
Expansion speed on the ground ~ 1 MLT hrs/min Maps to 10RE as 200km/s westward (250km/s along track)
Observed speed in space (from time delays) is ~250km/s From 10RE it maps on the ground to ~1 MLT hrs/min
Orientation of expansion needs further investigation (under way) Use remote sensing and finite gyroradius techniques
Note: is was no continuous expansion of the WTS. A new activation appeared Westward of an old one. Likely the norm?

22. Examples of THEMIS capabilities
Mende et al, GRL 2007

23. Tail 1 (Jan ’08 – Mar ’08) http://sscweb.gsfc.nasa.gov/tipsod/
Coast, Placement and Tail Phases
Coast phase dayside (May-Aug ’07)
Placement (Sep-Dec ’07)
Tail 1 (Jan ’08 – Mar ’08)

24. FTEs on TH-D: Detail

25. Sphere -,+ Sheath Sibeck et al., SM 22B-08
Dissection of an FTE by THEMIS
Sphere
Dusk MP
-,+
Sheath
Sibeck et al., SM 22B-08

26. Phan et al., SM 22B-01 Magnetopause reconnection event (May 21) TH-B
TH-C
TH-C
TH-D
TH-D
TH-E
TH-A
TH-E
TH-A
Phan et al., SM 22B-01

27. Magnetopause reconnection event, May 21 example - detail

28. Remote sensing of FTEs: dayside TCRs
Liu Jiang, SM11A-0316 B D C E A

29. Scheduled Cluster-THEMIS coordination intervals
Upcoming Tail Season Activities
Scheduled Cluster-THEMIS coordination intervals
Scheduled AMISR, Sondestrom radar scans
SuperDARN in THEMIS mode, w/ added midlat radars
Cluster-THEMIS, side view
Cluster-THEMIS, top view

30. Data availability

31. First publications by instrument leads
THEMIS Data Policy
Open data policy
Data on the street only 2 weeks after collection
Also, preliminary calibrations and overview plots
Also, software for analysis available
Credits. Always credit: NAS
Strongly recommend to consult PI/coIs on data before study
Editors will be requested to ensure above have been implemented.
First publications by instrument leads
Space Science Reviews papers
First data papers within
One compendium, demonstrates instrument and use of data
GRL special issue on first science results
Community
Tag team with individual instrument leads to learn use of data
Engage in scientific discussions with coIs
Acknowledgement sufficient, if for use of data alone
Co-author instrument providers if helpful in data interpretation

32. Expect first substorm results to be reported in ICS-9
Anticipating an Exciting Tail Season
Expect first substorm results to be reported in ICS-9

33. Join the THEMIS society!
The fun has just begun!
Do not miss out!
Join the THEMIS society!