THEMIS in the inner magnetosphere:
Review of current
• Summary of THEMIS results in the inner
magnetosphere
• Future mission operations discussion:
– Science targets
– What do we need to change (if anything)?
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
THEMIS Extension (FY10,11,12)
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Extended THEMIS Baseline (P3,P4,P5)
• At Inner Magnetosphere, Study Role of: • Using novel:
– ULF/VLF/EMIC waves on ion, electron
energization/losses
– Large electric fields on storm time ring current
– 0.1-2RE separations to resolve
temporal/spatial evolution of gradients
– daily conjunctions: PFISR, S-DARN
• Result:
– Comprehensive AC waves and E-fields models
P3 P4
P5
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
EMIC waves
1
Usanova et
al.,
GRL, 2008
3
- Driven by SW Pdyn
- Confined to L=5-6.5
2
- Structured, with good ground-space
correlation
- Potentially important for RB loss.
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Ring Current
Ions
Dst storm index
Wang et al.,
GRL, 2008
Electrons
TH-B
TH-B
TH-D
TH-D
TH-B
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.
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Substorm Injection
Westward Propagation
97A
Angelopoulos et al.,
First Results from THEMIS,
Space Sci. Reviews, 2008
046
Speed: 1MLT/min
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Injection Simulated
as localized pulse
Liu, Wenlon et
al., JGR, 2008
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Plasma Sheet
Injections
Runov et al.,
GRL, 2008
Ions, TH-C, B, E
Electrons, TH-A
-Nose structure, temporal
-Electron injection local, transient
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Generation of
whistler 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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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Whistler emissions
•
Cully 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
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
KH-wave driven FLRs: Agapitov et al., JGR, 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
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
FLR Polarisation
•
• as
•
•
Polarisation of Pc5 ULF
changes along THEMIS
orbit.
Agreement with twisted
eigenmode solutions
(Rankin et al., Kabin et al.)
Importance of FLR in
structure?
Data – Electric Field
Model –
Electric Field - m1
(poloidal)
Model –
Electric Field - m2
(toroidal)
Data – Magnetic Field
Model –
Magnetic Field - m1
[Sarris et al., 2008]
Model –
Magnetic Field - m2
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
FLR Statistics
[Liu et al., 2008]
• Wave power shows absence of storm time afternoon side Pc4-5
power.
Wave Power.
Occurrence rates.
Poloidal
Toroidal
Toroidal
Pc5
Pc5
Pc4
Pc4
Poloidal
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Summary
• THEMIS already presents significant present capability to measure:
– Waves, particles and their interactions from the radiation belts
out 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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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Instrument overview
EFIs
SCM
ESA
SST
FGM
Tspin=3s
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)
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Extended THEMIS Baseline (P3,P4,P5)
• At the Magnetotail, Study:
• With first ever:
– Nature of the near-Earth current sheet
– Dissipation of bursty fast flows
– Simultaneous dR-dZ separations, 0.1-1RE
– Clustered orbits study the 8-12RE region
• Result:
– Ability to map and model key
instability region
2010-04-10 00:00:00
FAST
Z
P4
P3
X
X
P5
Y
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
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:
• Using novel:
– Simultaneous dR-dZ separations at
0.1-0.5RE monitor inflow and outflow
– Cluster-like separations at subsolar
region
– Hall-physics of subsolar magneto-pause
reconnection, paves way to MMS
2010-04-10 00:00:00
Z
P4
P5
P3
[THEMIS
Coast Phase
Mozer et al.
GRL]
X
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THEMIS Inner Magnetosphere Review, Dec 20, 2008
Data availability
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THEMIS Inner Magnetosphere Review, Dec 20, 2008