Electromagnetic fields from pulsed electron beam experiments in space: Spacelab‐2 results

Abstract

During the Spacelab‐2 mission a small satellite carrying various plasma diagnostic instruments was released from the shuttle to co‐orbit at distances up to 300 m. During a magnetic conjunction of the shuttle and the satellite an electron beam modulated at 1.22 kHz was emitted from the shuttle during a 7 min period. The spatial structure of the electromagnetic fields generated by the beam was observed from the satellite out to a distance of 153 m perpendicular to the beam. Electromagnetic radiation at the fundamental and the harmonics of the modulation frequency was observed as well as broad‐banded electrostatic noise. The magnetic field amplitude of the strongest harmonics were comparable to the amplitude of simultaneously observed whistlers, while the electric field amplitudes were estimated to 1–10 mV/m. The observations are related to theories for radiation from pulsed electron beams.