One-dimensional model of relativistic electron beam propagation

Abstract

Numerical and analytic methods have been used to investigate the propagation of a relativistic electron beam through a grounded conducting plane into a region which either is vacuum or contains a neutral gas. The one-dimensional model used represents the behaviour of real beams whose radius is large compared with c/ omega b (the ratio of the speed of light to the plasma frequency corresponding to the beam density). In the vacuum case, the beam does not propagate but a moving potential well forms which could provide a mechanism for ion acceleration. When neutral gas is present, the beam propagates with a speed which depends on the rate at which the gas is ionized by collisions with the beam electrons.