ELECTRIC FIELD AND SEARCH COIL (EFASC) Fact Sheet
Investigation Overview
The Electric Field and Search Coil Instrument (EFASC) for the Radiation Belt Storm Probes Mission will provide identical instrument suites to fly on the two
RBSP satellites. This instrument suite will provide crucial measurements of the dc and wave electric fields and wave magnetic fields addressing each of the
major classes of acceleration mechanisms believed to operate in the inner magnetosphere. The instrument suite will also have sufficient capability to address
more speculative mechanisms those role is uncertain because of the measurement limitations of previous missions in this region of space.
Science Objectives
KEY INSTRUMENTATION
The overall objective of this investigation is to study the electric and
wave magnetic fields associated a variety of mechanisms causing
energetic particle energization, scattering and transport in the inner
magnetosphere. These mechanisms include magnetosonic waves
launched by interplanetary shock impacts on the magnetosphere,
substorm injection fronts, MHD wave mediated radial diffusion,
stochastic acceleration and scattering by high frequency waves, and
scattering by small scale intense plasma structures. The role of the
large-scale convection electric field in modifying the structure of the
inner magnetosphere and influencing these processes will also be
investigated. These processes cause the episodic acceleration of
electrons and ions to relativistic energies over time scales of seconds
to days. The measurements are of special relevance to the general
problem of collisionless particle acceleration in space and
astrophysical plasmas and also to the problem of mitigating the
hazards of energetic particle fluxes on space assets- a goal of LWS.
CHARACTERISTICS
Instrument Electric and Wave Magnetic Field
Measurement Quantities
Two spin plane component Ey, Ez (gse) at dc - 12 Hz (0.05
mV/m)
Spin axis component of Ex (gse) at dc -3 Hz (>3mV/m)
Two electric field spectra (nearly parallel and nearly perp to
B) between 1 Hz -12 kHz every 6 seconds
Two magnetic field spectra (B-LF) (parallel and perp to B)
between 10 Hz and 12 kHz once per 6 seconds
Spacecraft potential covering cold density from 0.1 to ~100
cm-3 once per second.
One high frequency electric field spectra from 4 kHz to 400
kHz every 6 seconds
Burst recordings of high frequency waveforms. The
maximum burst sampling rate is 12 kHz for 3-d E and 3-d B.
There will be 6 MBytes of rad hard memory
Teaming and Management
Relevance to NASA Science Goals
The EFASC Investigations is designed to provide a basic
understanding of the physical mechanisms responsible the
acceleration and transport of radiation belt particles.
Understanding and predicting the state of the near earth
radiation environment is a high priority of NASA’s Living
with a Star Program. The hazards of space weather impact
manned and robotic missions in space.
PI: John Wygant, University of Minnesota
Project Management: Dave Curtis, SSl, UC Berkeley
Systems Engineering: Ellen Taylor, SSL, UC Berkeley
Electric field sensors: J. Bonnell, SSL, UC Berkeley
DSP: R. Ergun, LASP, CU.
Search Coil: R. Strangeway, UCLA
Booms: P. Turin, SSL, UC Berkeley
Theory/Modeling Team: M. Hudson, Dartmouth College
SOC, Data Analysis, Delivery,Archiving: C. Cattell, UM
E/PO: C. Cattell, UM
Advisor/Mentor: F.S. Mozer, SSL, UCB
Mission Schedule
Resource Budget
MoI of Spin Plane booms plus SC boom
Total Mass (with contingency)
Primary Power
EFASC Data Rate
Sensors / Preamps
Search Coil
Magnetometer
(UCLA)
Preamps
(UCLA)
2382 kg m2
22.4 kg
8.0 W
~3248 bps
Phase A March 2006-March 2007
Phase B April 2007 to April 2008
Phase C /D May 2008 February 2011
Flight Instrument Delivery and Integration
January 2011 December 2010
Launch February 2011
Phase E March 2011-March 2013
Signal Processing
(in electronics box)
DSP (CU)
Analog, A/D
Digital Filters
Spectra (FFT)
BEB
(UCB)
Electric Field
Booms &
Sensors
(UCB)
Bias
Deploy
BEB: Boom Electronics Board
IDPU (CU)
Burst Memory,
SFR, Data &
Command
Data & Command
Real Year
Dollars
$19,997,486
Mission Cost
FY 2005
Dollars
$18,307,943
Cost
$4,999,371
$24,996,857.
$4,576,986
$22,884,929
Contingency
Cost +Cont