Summary of THEMIS results in the inner magnetosphere Future mission operations discussion:
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Transcript of Summary of THEMIS results in the inner magnetosphere Future mission operations discussion:
1 THEMIS Inner Magnetosphere Review, Dec 20, 2008
• Summary of THEMIS results in the inner magnetosphere
• Future mission operations discussion:– Science targets
– What do we need to change (if anything)?
THEMIS in the inner magnetosphere:Review of current
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THEMIS Extension (FY10,11,12)
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Extended THEMIS Baseline (P3,P4,P5)
• At Inner Magnetosphere, Study Role of:– ULF/VLF/EMIC waves on ion, electron
energization/losses – Large electric fields on storm time ring current
• Result:– Comprehensive AC waves and E-fields models
• Using novel:– 0.1-2RE separations to resolve
temporal/spatial evolution of gradients– daily conjunctions: PFISR, S-DARN
P3 P4
P5
4 THEMIS Inner Magnetosphere Review, Dec 20, 2008
EMIC waves Usanova et al.,GRL, 2008
1
2
3
- Driven by SW Pdyn
- Confined to L=5-6.5
- Structured, with good ground-space correlation
- Potentially important for RB loss.
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Ring Current
Ions ElectronsDst storm indexTH-B
TH-D
TH-B
TH-B
TH-D
TH-B
- Ions penetrate deep into the inner magnetosphere, and remain after storm.- Electrons also come close to Earth, but decay fast after storm recovery.
Wang et al.,GRL, 2008
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TH-C
DBA
E
Ygse
Xgse
D
B
A
2000kmTH-C
DBA
E
Ygse
Xgse
D
B
A
2000km
D
B
A
2000km
Angelopoulos et al.,First Results from THEMIS,Space Sci. Reviews, 2008
V ~
350
km/s
Speed: 1MLT/min
Substorm InjectionWestward Propagation
97A
046
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Injection Simulatedas localized pulse
Liu, Wenlon et al., JGR, 2008
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Electrons, TH-A
Ions, TH-C, B, E
Plasma SheetInjections
Runov et al.,GRL, 2008
-Nose structure, temporal-Electron injection local, transient
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Generation ofwhistler emissions
Li et al.,JGR, 2008
• Low and upper band chorus emissions correlate with 5-10keV electron anisotropy
– 10keV electrons at higher L-shells have sufficient anisotropy to generate observed wave power
– 1keV electrons can penetrate deep but don’t have the required anisotropy to generate chorus
– Higher plasma density results in higher amplitudes
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Whistler emissionsCully et al.,GRL, 2008
• Localized, large amplitude chorus emissions– Bursts of sub-second duration– Greater than100mV/m– L~3.5-5.5; dMLT = 1-3 hrs
• Mean/average not good description of wave field
11 THEMIS Inner Magnetosphere Review, Dec 20, 2008
• KH wave seen by THC,B,D,A– Couples to ULF wave on TH-E
• Driven ULF wave is localized– Phase change 180o at peak amplitude
KH-wave driven FLRs: Agapitov et al., JGR, 2008
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FLR Polarisation
• as
Data – Electric Field Data – Magnetic Field
Model – Electric Field - m1(poloidal)
Model – Magnetic Field - m1
Model – Electric Field - m2(toroidal)
Model – Magnetic Field - m2
• Polarisation of Pc5 ULF changes along THEMIS orbit.
• Agreement with twisted eigenmode solutions (Rankin et al., Kabin et al.)
• Importance of FLR in structure?
[Sarris et al., 2008]
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FLR Statistics
Occurrence rates.
Pc4
Pc5
Poloidal Toroidal
Pc4
Pc5
Poloidal Toroidal
[Liu et al., 2008]
Wave Power.
• Wave power shows absence of storm time afternoon side Pc4-5 power.
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Summary• THEMIS already presents significant present capability to measure:
– Waves, particles and their interactions from the radiation beltsout to the plasma sheet
• Continuous operations from solar min to solar max
• Can provide plasma sheet sources, measure ULF, EMIC waves for studying radiation belt dynamics
• Can provide rapid crosses of radiation belt electron phase space density
• Multiple satellites can provide information on phase and group velocity
• String of pearls configuration can resolve spatio-temporal ambiguities
• Critical importance will be storms in continuing and extended mission
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Instrument overview
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)
SST
ESA
EFIa
EFIs
FGM
SCM
Tspin=3s
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Extended THEMIS Baseline (P3,P4,P5)
• At the Magnetotail, Study:– Nature of the near-Earth current sheet– Dissipation of bursty fast flows
• Result:– Ability to map and model key
instability region
2010-04-10 00:00:00
P3P4
P5
X
Z
X
Y
• With first ever:– Simultaneous dR-dZ separations, 0.1-1RE
– Clustered orbits study the 8-12RE region
FAST
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Extended THEMIS Baseline (P3,P4,P5)
• At Subsolar Magnetopause, study:– Asymmetric reconnection: dynamics, evolution and
role of cold ions– Internal FTE structure and electron acceleration
• Result:– Hall-physics of subsolar magneto-pause reconnection,
paves way to MMS
2010-04-10 00:00:00
P3P4
P5 X
Z
[THEMISCoast PhaseMozer et al.GRL]
• Using novel:– Simultaneous dR-dZ separations at 0.1-
0.5RE monitor inflow and outflow– Cluster-like separations at subsolar region
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Data availability