Observations of Sub-LF electromagnetic field phenomena associated with modulated electron beams on STS-3

This report provides initial documentation of some of the Sub-LF (frequencies less than 30kHz) electromagnetic field phenomena observed during the first active electron beam/space plasma experiment on a Space Shuttle orbiter. The experiment took place in March 1982 as part of the third flight of an orbiter, and it was notable for its particularly complete instrumentation for plasma and electromagnetic wave diagnostic measurements. A number of anomalous electric and magnetic field phenomena are observed during the electron beam modulation experiments, including the generation of noise bands, extra harmonics, and a variety of side frequencies. In addition, discrete ELF tones are observed during some of the dc electron beam pulse sequences, and there are peculiarities in the harmonic structure of the electromagnetic fields produced during lower-ELF modulation of the electron beam. Studies of these effects are continuing.