Io - Electrodynamic interactions

1

• Conjugate response of the dayside magnetopause
  and dawn/dusk flanks using Cluster-THEMIS
  conjunctions and Ground based observations
• M W Dunlop, Q-H. Zhang
• M G G T Taylor, Y Bogdanova, J Berchem, D
  Constantinescu, J Eastwood, P Escoubet, A
  Fazakerley, H Frey, H Hasegawa, B Lavraud, Z-Y
  Pu, C Shen, D Sibeck, M Volverk, J Wild, J. Wang,
  E. Panov, J-K. Shi.
• ISSI team membership as above.
• Selection of co-ordinated events between Themis,
  Double star and Cluster.
• Covering the Epoch April-July 2007
• Cluster at large (multi-scale configuration) on
  dawn-side and flank
• Themis in string of pearls on dusk-side and
  flank
• Double Star TC-1 covers a few hours around local
  noon
• Periodic coverage with Geotail.
• Conjunctions occur over the whole range of local
  time at both high and low latitudes.

2

• Multi-point study themes dayside boundary

• Some Themis events analysed separately
• Comparative studies of FTEs and other transient
  phenomena
• Ability to cover both sides of the magnetopause
  simultaneously
• Potential to probe X-line extent, reconnection
  flow distribution and IMF Bz and By effects
• Magnetopause boundary layer and plasma sheet
• Dawn/dusk flanks and at high and low latitudes
• Comparative effects of lobe reconnection and K-H
  instability (northward IMF) on plasma sheet
• Extent of behaviour along the magnetopause and
  relation to ground or ULF signatures
• Comparative studies of dynamic response
• Generation of boundary and ULF waves at and
  inside the magnetopause
• Global magnetopause motion identified from wide
  LT coverage
• Close monitoring of response to Solar Wind
  pressure pulses or IMF
• Comparative Cluster-Double star configurations
  have been studied previously
• Included development and use of multi spacecraft
  analysis tools

3
Cluster-Double Star conjunctions I Dunlop et al
2005, 2007, 2008, Wang et al. 2006, Raeder et
al.2006, Fear et al.2007, Wang et al.2007.
Cluster
TC-1

• Coordination between Cluster and Double star
  lying north and south of the sub-solar point
  respectively reconnection line at low latitude
  generating series of opposite FTEs.
• Observation of both moving flux tube branches
  simultaneously
• Evidence for asymmetric extent of the LLBL
  (north/south)
• Reversal in IMF reconnection onset, change in
  (extent of) MP BL.
• Also coordination with Geotail and survey of FTE
  motions (Cooling)
• Global MHD dipole tilt dependence, controlling
  occurrence.
• FT shape and sampling) dependent on location and
  conditions.

4
Cluster-Double Star conjunctions V E-M fields
and waves in a thin magnetopause Silin et al.
2005, Trines et al. 2007.

• Multi-spacecraft sampling of electrostatic
  solitons and zonal flows
• Time shifted traces, in LMN, show burst of DC
  and AC E field in the magnetospheric side of the
  MP.
• Evidence of electrostatic structures supporting
  solitary drift modes running down the density
  gradient
• Statistics of wave power in the boundary (higher
  outbound)

5
Themis-Cluster-Double Star conjunctions Configurat
ions of the five Themis (red), four Cluster
(blue), Double Star TC-1 (light blue) and Geotail
(cyan) spacecraft in April 2007 (left) and June
2007 (right).

• During April/May TC-1 lies nearer noon and
  Cluster exits into the magnetosheath at the dawn
  terminator.
• The five THEMIS spacecraft in their string of
  pearls repeatedly skim the magnetopause at the
  dusk terminator.
• The middle panel shows orbit track segments
  within 2 hrs of a nominal magnetopause March to
  March 2007-8.
• Nearly the whole of the magnetopause is
  potentially covered
• THEMIS (black) scans the dusk-side
• Cluster scans the dawn-side
• TC-1 moves midway between them in LT.

6
MP morphology and FTEs Brief Survey of
highlighted conjunctions full 2007 list up to
end of June. Need review of July 2007 and
2008 Additional Bow Shock conjunctions or mixed
BS-MP coordination

• 14 June
• 28 May
• 28 June
• 3 May
• 21 June
• 23 April
• 1 May
• 6 June
• 27 April
• 30 May

7
14 June close conjunction all 10 s/c

• Solar Wind IMFBy, steady Pram (increasing)
• Geotail inside dawn flank msphere,
• adjacent to Cluster
• Possible FTEs on all s/c.
• East-west motions.

Themis s/c sequence
E
8
28 June Solar Wind north IMF turns By
steady Pram Geotail in magnetotail
Mirror modes?
MP not fitted.

Cluster/TH Z-2 Re TC-1 Z-5 Re.
Flank BL FTEs.
9
28 May fast MP motion
Solar Wind N/S IMF, low Pram Geotail in
magnetotail
Cluster/TH Z-1 Re TC-1 Z-5 Re.

10
28 May - multiple crossings
Check orientation and motion possible MP ripples
Cluster/TH Z-1 Re TC-1 Z-5 Re.

11
3 May MP motion east-west FTEs
Solar Wind IMF By (IMF turning northward),
steady Pram Geotail dawnside magnetosheath,
tailward of cluster Early train of FTEs at
Cluster.
TH Z-1 Re TC-1 Z-5 Re Cluster Z-12 Re.

12
21 June GB - FTE
Solar Wind variable IMF high Pram sudden
decrease 1015 UT
MP not fitted.
All Z-5 Re.
13
21 June SW structure in msheath
Compressed magnetosphere Pram sudden decrease
1015 UT
MP not fitted.
All Z-5 Re.
14
23 April Cluster in SW Solar Wind IMF reversal
to south Pram pulse increase Geotail
conjunction with Cluster
15
27 April MP motion missing Themis data? Solar
Wind IMF -By, steady increasing Pram Geotail
dawnside, tail magnetosheath
All s/c near equatorial

16
1 May
Solar Wind variable IMF, low Pram Geotail in
magnetotail
Cluster _at_ Z-15 Re
17
6 June Solar Wind IMF By, steady Pram Geotail
18
30 May Solar Wind IMF By, steady Pram Geotail
19

• Event highlights