Effect of a neutral N2 cloud on the electrical charging of an electron beam-emitting rocket in the ionosphere - Echo IV

The interaction of 114 moles of neutral N2 and a 40-kV, 80 mA electron beam was studied during the Echo IV rocket flight. Neutralizing return currents to the rocket body preferentially followed a route back through the region where the electron beam interacted with the cloud. Photometric observations of a complex luminous discharge accompanying beam injection are reported. Observations of 3914-A emission produced by the beam indicated a maximum neutral N2 number density of nearly 10 to the 15th power per cu cm. An oscillatory discharge with a frequency somewhat lower than the N2 (+) ion gyrofrequency was noted at one point.