Observations of radiation from an electron beam artificially injected into the ionosphere

This paper reports the observations of waves generated by a controlled beam of particles artificially injected into the ionosphere and magnetosphere. The measurements were made during the Electron Echo 1 experiment, in which an electron accelerator was carried to a height of 350 km in the ionosphere from Wallops Island, Virginia, on an Aerobee 350 sounding rocket. It injected into the earth's magnetic field over 3000 16-ms pulses of electrons with 40-keV energy and a current of 70 mA at pitch angles between 70 and 110 deg. The ejected fiber glass nose cone carried antennas and receivers to measure the electric field of waves generated by the beam. Associated with the electron beam was radiation detected at frequencies near the electron plasma frequency of the background ionosphere, near twice the electron cyclotron frequency in the whistler mode, and near zero frequency. Associated with the operation of an argon plasma generator used to keep the accelerator neutralized were continuous emissions detected at frequencies near the lower-hybrid resonance (LHR).