The Mission


Electric Field Instrument

The THEMIS Electric Field Instrument (EFI) measures the electric fields in three directions. One pair of sensors is deployed to 20 meters, the other pair to 25 meters. Two stiff telescopic booms extend sensors perpendicular to the four spinning cables and along the probe's spin axis.

Development Institution:
Sensors - Space Sciences Laboratory, University of California, Berkeley. Data Processing - Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, Boulder
EFI Lead
J. Bonnell(UCB)


Would you like to see:

Table of EFI Parameters
Frequently Asked Questions
EFI Modes and Data Products
How to Select an Appropriate Data Type
Sources of Non-Ideal Instrument Performance