Dynamic stabilization of plasmas by means of a high‐frequency‐modulated electron beam

Abstract

The stabilizing effects that a beam of longitudinally nonuniform density imposes on beam‐plasma instabilities are investigated using a hydrodynamic model adapted for an infinite, one‐dimensional beam‐plasma system. The electron beam is characterized by either of two types of longitudinal inhomogeneity—square‐wave or sinusoidal. The results, for the square‐wave type of inhomogeneity, indicate a disappearance of the convective instabilities below a threshold frequency as well as a reduction in the growth rate for the remainder of the spectrum. Similar results are obtained for the case of a high‐frequency sinusoidal pulsation of the beam density. Effects resulting from finite temperature plasma electrons are also discussed.