Measurements of 3914-Å light production and electron scattering from electron beams artificially injected into the ionosphere

Abstract

Measurements of electron backscatter and photon fluxes at 3914 A excited by a 40-keV artificial electron beam were made on an ionospheric sounding rocket. Echo 3 launched from Fairbands, Alaska, on April 17, 1974. The backscattered electron fluxes were found to have a constant value independent of altitude, indicating no dependence on the atmospheric density and being several orders of magnitude higher than that predicted by Coulomb scattering. This result confirms measurements on the Echo 1 and 2 experiments. The origin of this anomalous scattering has not been identified. In contrast, photon emission from the ambient atmosphere excited by the beam at 3914 A varied directly with the change in the density of N$sub 2$ molecules. A rocket 'halo' of high-intensity backscattering and photon emission accompanied beam injections close to 90degree local magnetic pitch angle and was probably caused by beam scattering from the rocket.