FORMATION OF A PULSED ELECTRON BEAM IN A PLASMA-CATHODE SYSTEM UNDER FOREVACUUM PRESSURES

摘要

Results of an experimental study of the features of the production of pulsed beams by a plasma electron source operating in the forevacuum pressure range (5-15 Pa) are presented. For this pressure range, the emission properties of the plasma are substantially affected by the backward ion flow generated in the regions of formation and transport of the electron beam. It has been shown that in experimental conditions the ratio of the current of backward ions to the current of the electron beam can reach 10%, which is an order of magnitude greater than the same parameter for electron sources operating in the pressure range that is conventional for devices of this type (0.01-0.1 Pa). The principal factors that impose an upper limit on the beam current in a plasma-cathode source are analyzed.