EFW Data Products/ProcessingVan Allen Probe SWG

San AntonioSeptember 2104

J.R. Wygant, J. Bonnell, Aaron Breneman,S. Thaller and the EFW Team

First panel is the EFW spin fit (10.5 s) electric fieldin ~ dawn-dusk direction.This measurement is dominated by waves with amplitudes >32 mV/m ptp during during every storm as indicated by SYM H (third panel).

The second panel is the dawn-dusk electric field averaged over 10 minutes from both spacecraft (superposed). This is nomally the convection electric field- but it also includes contributions fromm injection events.

Notice the convection electric field is directed preferentially inthe positive dawn-dusk direction- the direction of sunward convection.

Notice also the convection electric field is often peaks at ~4 mV/m which is very comparable to the magnitude of the "solar wind electric field" (Vx sw x Bz sw). The solar windelectric field and the measured RBSP electric fields are largestduring the main phase of geomagnetic storms and smallerduring the recovery phase.

The bottom panel shows the solar wind flow pressure and Bmag. These typically are enhanced at the beginning of thestorm and models indicate thesubsolar magnetopause can move within ~8-9 Re durng the intial phases of the storm whenULF are strong. This may lead to effective radial transport outward and loss of particles throug magnetopause shadowing.

Towards the end of the storms, during periods of lower flow pressure, when the estimated position of the magnetopause is outwardmany storm have large wave electric fields. These are times when relativistic fluxes increase to and often above the pre-storm levels.

includes only EFW above 3.2 Re

SYM-H

Ey (10 min ave) – Convection- Efield

Ey (10.5s ave) Waves/ Injection Events

ECT REPT/MagEIS Electrons

May- June 2013 Storms

Solar Wind Pressure

Summary

Almost all intervals of radiation belt increase or decrease are associated with large amplitude electric fields associated with waves 1-5 minutes

Waves at the beginning of storms are often associated with solar wind pressure increasesthat move the magnetopause close to the Earth.These periods are aasociated with decreases.

Wave occuring after the pressure enhancementsoften are associated with electron increases

Presently available on UMN EFW Website:L2 cdfs which include:1) Ey mgse Ez mgse spin fit resolution ( SC motional field subtracted)2) Spacecraft potential(V1+V2)/23) Spectral data 30 Hz to 8 kHz: E12, Bscw4) Filter band data peak and average (2 Hz to 8 kHz) in 7 frequency bins; two quantities: E12 and Bscw5) Ey mgse Ez mgse (16 Hz/ 32 samples/s)6) SC position GSE7) SC spin axis unit vector GSE, 8) Lvalue, MLT, MLAT

New L3 CDFs are about to be processed 1-2 weeks:1) Ey mgse Ez mgse in the Earths corotational frame2) Density3) All information above

EFW burst data 3 E, 3 Bsc, V1-V6 is posted on a UCB SSL website. It is downloadable. Software to process this data is also posted and can be downloaded: TDAS

EFW burst data is posted on a UCB SSL website. • The TDAS software to convert this to L-2, L3 version scientific data

products (mgse, GSE coordinate system; spectograms, convolution over gain-phase response functions etc) is available to the scientific community and has been described in numerous data access workshops at GEM and AGU.

The burst data consists of :• 3 components of the E-field in rotating SC frame• 3 components of the search coil B-field • V1-V6 Single probe measurements.

• The files for these playback are often quite large: 6 quantities x 16.4 ksamples/s for 30 minutes to 5 hours. They are collected during active periods and are intermittent.

• It can take hours to transfer these files over the internet and many computers do not have sufficient memory to process them.

• It would be quite difficult for the cdaweb to assimilate this data.

The EFW team has also posted survey plots which can be viewed on the UMN EFW website and also downloaded as pdf files.

These plots contain the L2 version quantities described in the previous slide plus information on spacecraft relative positions.