The influence of an electronegative gas admixture on the intenseE-beam transport and induced plasma currents in argon

The propagation of an electron beam, with electron energy ~1.2 MeV, beam current ~8 kA, and an induced plasma current is investigated using a metal drift tube ~0.5 m long filled with argon at atmospheric pressure. The behavior of electron concentration and electron temperature was calculated for several concentrations of the SF₆ admixture. The comparison of the results of the experiments and numerical calculations shows that the dropping of plasma current when electronegative gas is added is due to the electron attachment to the SF ₆ molecules. The results of the experiment and the calculations provide the evidence of at least three mechanisms responsible for the increase of the REB transport efficiency when electronegative gas is present