General intense electron beams by means of a contracted arc discharge

Abstract

Two types of contracted arc discharge are investigated with a view to generating intense electron beams over a wide pressure range (1–10−3 Pa). For an arc discharge with a hollow cathode and anode, an electron beam corresponding to a current of up to 300 A and a pulse length of 25 µsec is obtained at a pressure of 1–10−1 Pa in the accelerating gap with an accelerating voltage of up to 15 kV. At pressures of 10−2–10−3 Pa, emitting plasma is created by a low-pressure arc discharge on the basis of a Penning cell. Three discharge systems operating in parallel are used to increase the working life of the cathode and improve the current density distribution of the beam. An electron beam of diameter 200 mm with a current of up to 125 A and a pulse length of 50 µsec is obtained.