Polar Electric Field Instrument (EFI) Data Archive
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OVERVIEW
This archive provides plots or ASCII files of electric field data from the Polar Satellite at the following data rates:
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Burst:
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Data at various rates > 1000 samples/second depending on the telemetry mode.
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Real time:
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20, 40, or 80 samples/second depending on the telemetry mode.
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Spin period:
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One point every six second spin period.
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The electric field data is available in GSE and GSM coordinates. Also presented are the spacecraft potential and
plasma density deduced from it at data rates from 0.17 to 8000 Hz; and the spacecraft orbit and attitude parameters.
Two types of electric field data, E_0 and E_Dot0, are available. E_0 is computed from the spin plane measurements
and the assumption that the electric field component along the spacecraft spin axis was zero. The E_Dot0 data are
computed from the two spin plane components and the assumption that the parallel electric field was zero. If the
Z-direction is the spin axis, the assumption that the parallel electric field is zero gives Ez = -ExBx/Bz - EyBy/Bz.
This computation is limited to the cases that |Bz| is greater than or equal to 2 nT and both |Bx/Bz| and |By/Bz| are
less than or equal to 5.
The measured electric field is reduced by the conducting wire booms such that the measurement underestimates the
true field by a factor between 1 and 1.3, depending on plasma conditions. The constant factor 1.2 has been used in
the production of this data set. There is a sunward electric field that is produced by asymmetries between the
sunward and anti-sunward sensors and that has a magnitude of 0-2 mV/m, depending on plasma conditions. This
offset has been set to 1.2 mV/m in the production of this data.
NO DATA HAS BEEN REMOVED DUE TO TELEMETRY NOISE, CROSS TALK, INSTRUMENT OPERATION IN AN
INCORRECT MODE, ETC. THUS, THE USER MUST BE CAUTIOUS WHEN INTERPRETING THIS DATA.
The magnetic field data is also available, at Real time and Spin period time resolutions, in GSE and GSM coordinates.
The magnetic field and the electric field have been updated according to the latest calibrations for the magnetic field,
provided by the MFE experimenters. For further information about the magnetic field, please go to the MFE Website.
The Polar EFI PI, Forrest Mozer, is available at fmozer@ssl.berkeley.edu to assist with data interpretation.
This archive was prepared by Jack Vernetti and Winston Teitler.
To get plots or ASCII files of Polar EFI data, click "Continue". For a description of the available data, click "Descriptions".
For other Polar Data sites: