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13-4 Sept. 2008 EFW INST+SOC PDR
EFW Science Overview
Professor John R. Wygant (PI)University of Minnesota
23-4 Sept. 2008 EFW INST+SOC PDR
EFW Instrument OverviewRBSP EFW Features Four spin plane booms (2 x 40 m and 2x 50 m) Two spin axis stacer booms (2x6 m)Spherical sensors and preamplifiers near outboard tip of boom (400 kHz response)Flexible boom cable to power sensor electronics & return signals back to SCSensors are current biased by instrument command to be within ~ 1 volt of ambient plasma potential. Main electronic box (sensor bias control
filtering, A-D conversion, burst memory, diagnostics, mode commanding, TM formatting )
EFW Science quantities include: • E-fields:(V1-V2, V3-V4, V5-V6)
•Interferometric timing: SC-sensor potential (V1s, V2s, V3s, V4s, V5s, V6s)•SC Potential : (V1+V2)/2, (V3+V4)/2
Interface to EMFISIS instrument Electrostatic cleanliness spec: variations of potential across spacecraft surfaces smaller than 1 Volt.
+Z4 3
5
6
2
1Not to Scale
33-4 Sept. 2008 EFW INST+SOC PDR
Investigation TeamRBSP
Project OfficeAPL
EFW PIJohn Wygant
UMNRBSP SWG
EFW Co-I teamEFW PM
Keith GoetzUMN
EFW CAMKim Cooper
APL
LASP leadBob Ergun
LASP
MechanicalPaul Turin
UCB
SEDave Curtis
UCB
UCB PMJohn Bonnell
UCB
ElectricalMichael Ludlam
UCB
Flight SoftwarePeter Harvey
UCB
SMARon Jackson
UCB
DFBSusan Batiste
LASP
LASP PMMary Bolton
LASP
FinanceKate Harps
UCB
Ground SWWill Rachelson
UCB
UCB leadJohn Bonnell
UCB
43-4 Sept. 2008 EFW INST+SOC PDR
Science Objective: Measure electric fields associated with a variety of mechanisms “causing particle energization and scattering” in the inner magnetosphere.
These mechanisms include: Energization by the large-scale “steady state and storm time convection E-field” . Energization by substorm “transient fronts”propagating in from the tail. “Radial diffusion of energetic particles” mediated by “ULF waves”. Transport and energization by interplanetary “shock generated transient fronts.” Adiabatic and non-adiabatic energization by “electromagnetic and electrostatic”
waves and (“random”) structures .
Level-1 Science and Measurement Objectives (1)
53-4 Sept. 2008 EFW INST+SOC PDR
Mechanisms associated with energetic particle acceleration and transport (B. Mauk/APL)
63-4 Sept. 2008 EFW INST+SOC PDR
The shock induced magnetosonic wave created a 5 order of magnitude increase in 13 MeV electronfluxes in <100 seconds resulting in a new radiation belt that lasted two years
The large scale electric field produced a ~70 kV potential drop between L=2 & L-4and injected ring current plasma. dDst/dt= - 40 nT/hr
MHD waves: an important mechanism for radially diffusing and energizing particles.
CRRES measurements of the E-field during a pass through the inner magnetosphere: interplanetary shock induced electric field, large scale MHD waves,
and enhancement in convection electric field.
E-Fields in the Active Radiation Belt
73-4 Sept. 2008 EFW INST+SOC PDR
Level -1 Science Objectives for EFW High Time Resolution Burst Measurements:
....derive and determine electrostatic and electromagnetic field amplitudes, frequency, intensity, propagation direction, spatial distribution and temporal evolution with sufficient fidelity to calculate wave energy, polarization, saturation levels, coherence, wave normal angle, phase velocity, and wave number for a) VLF and ELF waves, and b) random, ULF, and quasi-periodic electromagnetic fluctuations.
.....determine the types and characteristics of plasma waves causing particle energization and loss including wave growth rates; quantifying adiabatic and non-adiabatic mechanisms of energization and loss........; determining conditions that control the production and propagation of waves.
EFW focuses on large amplitude low frequency electric fields, density perturbations, and inter-sensor timing. EMFISIS measures higher frequency and lower amplitude waves (Chorus) and the upper hybrid line frequency(plasma density) are measured by EMFISIS.
83-4 Sept. 2008 EFW INST+SOC PDR
Observations of large amplitude turbulent electric fields
E~500 mV/m Duration of spike 20-200 Hz Polarized perpendicular to B B~0.5 nT (not shown) Hodograms for E and B Complicated
quasi 3D structure full 3D and 3DB Waves electrostatic with phase fronts
~perp to B Large amplitude thermal plasma
variations measured from SC potential variations:Result in order of magnitude changes in index of refraction wave time scales: trapping motivates SC potential measurements
Position R=5.2, Mlat 25 deg, MLT=0.5
Observed during nearly conjugate ~400 keV electron microburst interval by low altitude SAMPEX.
93-4 Sept. 2008 EFW INST+SOC PDR
EFW Amplitude vs Frequency
103-4 Sept. 2008 EFW INST+SOC PDR
EFW/EMFISIS Amplitude vs Frequency
113-4 Sept. 2008 EFW INST+SOC PDR
Time Duration of Intervals of Low Frequency Bursting Necessary for Understanding Wave Fields Responsible for Scattering/Acceleration of Energetic Particles
Structures Generating Small Scale Waves
Duration Events / day Total Burst Duration
Substorm injection front
600s 5 2000 s
Boundary between ring current and plasmasphere
600s 2 1200s
ULF/MHD wave fields Selected intervals
400s
2 800s
Shock induced magnetosonic waves
~ 1 minutes 0.005 Negligible
Bursts at Radial Distances of 2.0-5.8 Re (0.5 Re intervals)
60s 16 960
Total Seconds of Burst 1 Data
6040 s
123-4 Sept. 2008 EFW INST+SOC PDR
EFW Targeted Energization/Transport Mechanisms and Structures
Mechanism/ Structures
Duration E-Field* (Spin plane)
E-field* (Spin axis)
Cold density (SC pot)
Interfer-ometric timing
1) Interplanetary shock impact
1-300 s 1 -300 mV/m
2 -300 mV/m
1-50 cm-3 ( n/n<50%)
NA
2) Injection events 5-600 s 1- 500 mV/m
2- 500 mV/m 1-50cm3 ( n/n<50%)
NA
3) Convection electric field
300 -36,000 s
0.3-15 mV/m
2-15 mV/m NA NA
4) MHD wave driven radial diffusion
10-600s 1- 40 mV/m
2- 40 mV/m
1- 50 cm-3 ( n/n<50%)
NA
5) Small scale/ large amplitude wave/ random structures
5 ms- 5 s
0.1-500 mV/m
2-500 mV/m 1- 50 cm-3
( n/n<50%)
Timing: 0.066 ms Velocity: 0-500 km/s
6) Plasmapause NA NA NA 1- 50 cm-3 ( n/n<50%)
NA
* Sensitivity for spin plane electric field larger of 0.3 mV/m or 10% of magnitude; for spin axis larger of 4 mV/m or 20% of magnitude; For small scale structures sensitivity is larger of 0.1 mV/m or 10%of magnitude.
133-4 Sept. 2008 EFW INST+SOC PDR
Measured and model average large scale convection electric field in inner magnetosphere. Traces are for different values of geomagnetic activity. Kp varies: 1-8. Quiet time field accurate to <0.2 mV/m. RBSP ~twice as accurate.
Requirement is larger of either <0.3 mV/m or 10% of magnitude of E for Radial distance > 3.5 Re.
Accuracy of Large Scale Electric Field Measurement
143-4 Sept. 2008 EFW INST+SOC PDR
Spin plane component of E-field at DC-15 Hz (>0.3 mV/m or 10% accuracy) over a range from 0 to 500 mV/m at R>3.5 Re
Spin axis component of E at DC-15 Hz (>4 mV/m or 20% accuracy) over a range from 0-500 mV/m at R>3.5Re.
Spacecraft potential measurements providing estimates of cold plasma densities of 0.1 to ~50 cm-3 at 1-s cadence (dn/n<50%).
Burst recordings of large amplitude (Req.: 0-500 mV/m Capability: 0-4V/m) E-fields ; B-fields and cold electron density variations 0-100 cm-3 with accuracy of 10% (derived from SC potential) over frequency range from dc to 250 Hz.
Interferometric timing of intense (>300mV/m) small scale electric field structures and non-linear waves: timing accuracy of .06 ms for velocities of structures over 0-500 km/s.
Low noise 3-D E-field waveforms to EMFISIS 10 Hz to 400 kHz with maximum signal 50 mV/m. For spin plane sensors: a dynamic range of 100 dB & sensitivities of 3 x 10-14 V2/m2Hz (TBR) at 1 kHz and3 x 10-17 V2/m2Hz (TBR) at 100 kHz. For spin axis sensor pairs the dynamic range and sensitivity is an order of magnitude less.
Driving MRD/ELE Measurement Requirements
153-4 Sept. 2008 EFW INST+SOC PDR
Measurement Dynamic Range
Sensitivity (driving)
Frequency Range/Timing
Req; EFW MRD ELE
Req: EFW Inst.
Difficulty
Spin Plane Electric Field
0.3-500 mV/m
> 0.3 mV/m or 10% of signal for R>3.5 Re
15 Hz 38 46 Medium
Spin Axis Electric Field
2-500 mV/m > 2 mV/m or 10% of signal for R>3.5 Re
15 Hz 42 51 Medium
Cold Plasma Density (<30eV)
0.1 -50 cm-3
n/n ~50% 0.5 Hz 55 47 Easy
Spin E-field
0.3-500 mV/m
1.0 mV/m @ 50 Hz
3-D B 90 dB 0.3 pT @ 100 Hz
Small Scale Large Amplitude Wave/ Structures
n 1-50 cm-3 n/n ~10%
250 Hz* * in change matrix
42 spin 47 axial 71, 59
49 spin 52 axial 44 50
Easy
Interferometric Timing
0-500 km/s (0.1-30km)
NA 0.06 ms
61 45 Easy
EMFISIS Interface 3 D Wave E-field
90 dB (TBR)
Spin plane: 3x10-14 V2/m2Hz @ 1 kHz 3 x 10-17V2/m2Hz @ 100 kHz (Spin axis x 100 less sensitive)
10 Hz- 400 kHz
244,246 36, 208 Medium
Primary Measurement Requirements Flow to Instrument
163-4 Sept. 2008 EFW INST+SOC PDR
LOGIC
AXB-01
LDO REG
+5V +15VF-15VF
DOOR2
BEB PWR -225V
BEB PWR +5VA
INSTRUMENT DATA PROCESSING UNIT (IDPU)
128K x 8
+5V +15VF-15VF
SYNC
FLT PWR1-6
Z80 CPU
SCM (X, Y, Z)
BACKUP56 D,S
FLT PWR1-6
S
FGM (X, Y, Z)
ANALOG FILTERING AND GAIN
MTR3
ACTEL
IMONs
DACs
+X
VSPHERE(V1-V6)
- +
IDPU PWR: +3.6VD
STATE1
DOOR5-6-Z
MTR5
+5V +15VF-15VF
POWER CTRL BOARD (PCB)
T
BEB ANALOG HK
+5V +15VF-15VF
RBSP EFW BLOCK DIAGRAM RBSP_EFW_SYS_100E CURTIS 2008-AUG-14
1.5V
USHER1-6
x6
-X
BEB PWR +225V
+5V +15VF-15VF
FLT POWER
V6
FILTER, I/F
TEMP6
INST & SC I/F
VMONs
FLT GND1-6
+Y
STATE4
MTR1
AXB-02
BEB ANALOG HK
ACTEST1-6
E x B, DFT, Waveforms
HTR 5
SERIAL TELEM-Y
IDPU PWR: -10V
STACER 5-6
FLT PWR, FLT GND 1-6
STATE5
- +
DIGITAL FIELDS BOARD (DFB)
MUX
DFB TLM (2)
AXB BOOM PWR
32K x 8PCB CMD, CLK, STB
FLOATING GND
MTR2
IDPU PWR
+28V+3.6VD+1.8VD
+5VD
S
BEB PWR +5VD
VMONs
ACTEL
DOOR1
DATA CTRL BOARD (DCB)
SPB BOOM PWR
DCB/DFB POWER
x3
STATE3
BEB CTRL(11)
3.3V
LVPS_SYNC
TEMP 5-6
ADC
HTR 6
V5
x3
Preamp
IDPU PWR: +1.8VD
MTR 5-6
PCB CMD, CLK, STB
+28V +225V-225V
SC IDPU PWR
256MB
DFB CMD, CLK, TLM(2), SYNC
SCM (X, Y, Z)
DOOR 1-4
LDO REG
STACER6, BACKUP56S
SPB-01
V4
x3
FLASH
TEMP5
- +
IDPU PWR I/F TOSPACECRAFT
SPB-04
PCB ANALOG HK
MUX,ADC (2)
+5V +15VF-15VF
PCB_ANALOG_HSK
BEB_CTRL(11)
DOOR6, BACKUP56D
BEB PWR -10VA
IDPU PWR
x6STATE2
GUARD1-6
DFB CMD, CLK (8MHz)
LVPS_SYNC
- +
- +
SPB-03
BEB PWRBOOM ELECTRONICS BOARD (BEB)
SERIAL CMDS
IDPU PWR: +5VD
PROM
FLUXGATEMAGNETOMETER
32GB
LOW VOLTAGE POWER SUPPLY (LVPS)
IDPU PWR: +5V
SPB-02
1.5V
EFW (X, Y, Z)
- +
T
EFW (X, Y, Z)
STACER5, BACKUP56S
t
t
V3
DIFFERENTIAL DRIVERS
MTR6
EMFISIS MEB
3.3V
BEB/PCB POWER
+28V +5VD
STATE6
DOOR5, BACKUP56D
BEB PWR +10VA
V2
MTR4
STATE1-6
MUX
BACK PLANE
SRAM
MTR 1-4
S
DATA I/F WITH SPACECRAFTDOOR4
IDPU PWR: -5V
HTR 5-6
INST CTRL, I/F
SDRAM
+Z
+28V +5V-5V
+10V-10V
IDPU PWR: +10V
BIAS1-6
DOOR3
V1
DFB SYNC (1Hz)
FGM (X, Y, Z)
1PPS / SPIN PULSE
+28V +10V-10V+5V
173-4 Sept. 2008 EFW INST+SOC PDR
BACK-UP SLIDES
183-4 Sept. 2008 EFW INST+SOC PDR
Effect of Attitude Uncertainty in E-VxB subtraction accuracy
193-4 Sept. 2008 EFW INST+SOC PDR
RBSP Level 1 Baseline Measurement Goals Related to EFW
3-D Electric Field from DC to 10 Hz on two platforms (4.1.2.10)
3-D Wave Electric Field 10 Hz -10 kHz (Spectral: 20 bins) (4.1.2.9)
The mission shall be capable of taking concurrent full 3D magnetic and 3D electric waveforms with at least 20 k samples/s, which is sufficient to support an unaliased bandwidth of 10 kHz, to determine the propagation characteristics of waves up to 10 kHz. (4.1.2.14)
3-D Wave Magnetic Field 10 Hz-10 kHz (Spectral: 20 bins) (4.1.2.8)
Plasma Density 1 second resolution on two platforms (4.1.2.11)
203-4 Sept. 2008 EFW INST+SOC PDR
SAMPEX in low altitude orbit encounters outer radiation belts ~10 minutes after Polar about 1 hour in MLT
distant
SAMPEX observes rapid time variations (0.1-1 seconds) in 500 keV electron fluxes
Fluxes vary by almost order of magnitude
Consistent with strong scattering of electrons due to waves (similar to Cattell et al. this meeting)
Coincides with Polar L-value
213-4 Sept. 2008 EFW INST+SOC PDR
Large Amplitude AlfvenWave at PSBL with imbedded largeamplitude LH “type” waves
R=5.2 Re, 0.82 MLT, MLAT~25 deg
Ez ~300 mV/m By~100 nT
Propagate parallel to B tpwards Earth
Vphase~ 3000-10000 km/s
E-Field (mV/m)(~800 Hz)
Z GSM
B-Field (nT)Y GSM
(8 Hz) Notice:Imbedded bursts of highfrequency waves ~1 V/mptp (greater in other components)
25 duration burst
Low freq
1000
-1000
0
100
0
50
223-4 Sept. 2008 EFW INST+SOC PDR
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
233-4 Sept. 2008 EFW INST+SOC PDR
Each EFW instrument shall consider a spin axis DC electric field (survey) measurement to be unobtainable when: 1) the spacecraft is in Earth shadow; 2) the spin axis boom pointing requirements are not met; 3) magnetic field data is not within required accuracy; 4) spacecraft attitude information is not within required specifications; 5) spacecraft velocity measurements are not within specification; 6) the electrostatic cleanliness specification is not capable of controlling differential charging of spacecraft surface (i.e., differential charging across spacecraft surface > 1 volt);
Validity Conditions for Spin Plane Electric Field Measurement
MRD ELE 494
243-4 Sept. 2008 EFW INST+SOC PDR
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