The Low Energy Electron-Proton Experiment was designed to continually monitor the spectra and pitch angle distributions of electrons and protons from 0 to 22 keV to aid in understanding the mechanisms responsible for substorms. The particle sensors were electrostatic analyzers using electron multiplier detectors. Unfortunately , little data have been obtained because of an unknown mode of interference between the experiment and the spacecraft.
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R. L. Arnoldy (1975) studied this question.
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