Exploration of Oscillating Beam-plasma Fields with a Transverse Electron Beam†

Abstract

Some experiments are described in which a low-pressure oscillating electron-beam and plasma system is explored by a second electron beam transverse to the first. The energy spread (scattering) found in the main system when high frequency, probably electrostatic oscillations are occurring, is found to be present in the exploring beam only when the latter is in or has traversed a section of the main discharge where oscillations and scattering can be detected. With the discharge described, the magnitude of the scattering in the transverse beam was about 8 v when the scattering in the main beam was about 14 v. The results appear to be compatible with considerable randomization and possible break-up of the main beam by the oscillations.