RBSP-THEMIS Working Group Status

RBSP-THEMIS Working Group Status
October 2012
Leverage complementary nature of the RBSP & THEMIS missions to achieve our goals in
radiation belt and ring current studies.
Develop observational campaign as function of mission phase to solve outstanding mysteries
in the radiation belt and ring current physics.
Wednesday, November 2, 11
THEMIS Instruments & Modes
Four Modes: (1) Slow Survey; (2) Fast Survey; (3) Particle Burst; (4) Wave Burst
Fast survey mode intervals are set in advance;
Particle and Wave bursts can be either set or triggered during fast survey intervals
Instrument
Slow
Fast
FGM Fluxgate Magnetometer
FIT
0.25s
0.008s
SCM SearchCoil Magnetometer
FBK
FWS
FCW
EFI Electric Field Instrument
Particle Burst
FIT/FGK 0.12s/WF/FWS
Wave Burst
FCW
ESA Electrostatic Analyzer
MOM
RDF
Full Cadence FDF
SST Solid State Telescope
Spectra
RDF/IFDF
Full Cadence FDF
FIT: 3s spin period fit, MOM: 2s onboard moments, RDF: 3s reduced angular particle
distribution function, FDF: Full angular particle distribution function, 3s IFDF ion full
distribution function, FCW: Full cadence waveforms, FBK: 4s filterbank wave spectra,
FWS: Fourier wave spectra, WF: waveforms.
Wednesday, November 2, 11
Science Planning Tasks
Outline joint RBSP and THEMIS science campaigns as a function of the RBSP
mission phase;
For each campaign specify three THEMIS parameters can be tailored to
support RBSP science studies:
(1) the distances separating spacecraft along their common orbit;
(2) the portion(s) of the THEMIS orbit where fast survey should be taken;
(3) the phenomena that can be used to trigger burst modes;
Wednesday, November 2, 11
8 Science Campaigns
Dawn-Dusk Differences
(Fall 2012)
Magnetopause Losses
(Winter 2012-2013)
Dawnside Waves & Electron Drift
(Spring 2013)
Ion Injection & Energization
(Summer 2013)
Duskside EMIC Waves
(Fall 2013)
Effects of SW Pressure Variations
(Winter 2013-2014)
ULF Waves
(Spring 2014)
Electron Injections
(Summer 2014)
Wednesday, November 2, 11
Local Loss Mechanisms
⇥
kk v k =
e
On the course of their drift motion around Earth radiation belt electrons can
resonantly interact with various plasma waves which can locally energize as well as
scatter particles into the loss cone leading to permanent loss of particles from the
belt via precipitation into the atmosphere. Two leading candidates for local loss
mechanisms outside of the plasmasphere are EMIC waves at duskside and whistler
chorus waves at dawnside.
Wednesday, November 2, 11
EMIC Waves
Minimum Resonance Energy
EMIC Waves @ AMPTE/CCE
Spatial Distribution
Global impact of EMIC waves on losses across the
outer radiation belt depends on spatial extent and
spectral properties of the waves.
[Anderson et al., 1992a]
Wednesday, November 2, 11
Whistler Chorus
[Cattell et al., 2008]
Whistler chorus waves (including large amplitude events) can potentially contribute to both rapid
energization and atmospheric loss of particles from the belt.
Wednesday, November 2, 11
Dawn-Dusk Differences
(Fall 2012)
Recommendations to THEMIS:
1) Small interspacecraft separation distances to
separate spatial and temporal effects in particle
and wave populations.
2) Fast survey mode from geosynchronous
through perigee to study ion flux levels and pitch
angle distributions along with EMIC mode waves.
3) Burst modes triggered by EMIC wave activity.
Wednesday, November 2, 11
Magnetopause Losses
Initial conditions:
105 electrons
K=2 MeV @ L=6.7
µ=2.3⋅103 MeV/G
f (L, t=0): B&A2000
L ≡(B0/B)1/3
Rapid ring-current intensification during storm main phase produces outward expansion of
electron drift shells. Electrons previously drifting around Earth are transferred onto trajectories
intersecting the magnetopause and are permanently lost from the belt in about 2.5 hr after the
storm onset from L > 5.
Wednesday, November 2, 11
Magnetopause Losses
(Winter 2012-2013)
Recommendations to THEMIS:
1) Large interspacecraft separation (4-8-12)
simultaneous measurements on the inbound and
outbound legs for continuous monitoring of
losses.
2) Fast mode operations in the post-noon sector
for simultaneous monitoring EMIC waves.
3) Burst modes triggered by large-amplitude
waves and and interplanetary shocks.
Wednesday, November 2, 11
What are the Mechanisms of RC & Seed Population
Energization and Transport?
Steady-state convection
Impulsive transport, DF
[Grocott and Yeoman, 2006]
[Runov et al., 2009]
Wednesday, November 2, 11
LFM-RSM Simulations
Wednesday, November 2, 11
Impulsive Transport
Propagation of DF to the Inner Mangetosphere
Energization and Transport of O+ by DF
- How deep can injection propagate into the inner magnetosphere?
- Are the events distributed continuously by size and magnitude?
- Can we identify their solar wind/geomagnetic control parameters?
- Are the events at RBSP different from the events in the outer magnetosphere (x<-10RE)?
Wednesday, November 2, 11
Ion Injection & Energization
(Summer 2013)
Recommendations to THEMIS:
1) Wide spacecraft separation to ensure continual
monitoring of the particle source population in
the plasma sheet.
2) Fast survey mode on the outbound leg near
the apogee.
3) Burst modes triggered by DFs.
Wednesday, November 2, 11
Next Steps
1) Expansion of scope: Resonance, ERG....
2) Real work needs to be done.....
Wednesday, November 2, 11