Plasma created in a neutral gas by a relativistic electron beam

Theoretical and experimental studies have been made of the plasma current created by an electron beam propagating in a neutral nitrogen gas. Beams of ∼ 2 and 20 kA/cm2 and energies ∼ 3 and 0.25 MeV were investigated, and agreement within about ± 15% between theory and experiment was found for the net current. The model used includes primary and secondary ionization processes, electron-neutral and electron-ion collisions, recombination and depletion of N2 molecules. Detailed results for the spatial and temporal variation of the plasma density (∼ 1015 cm−3) and temperature (∼ 5 eV) are presented.