Plasma Heating by Intense, Relativistic Electron Beams

Abstract

A partially ionized helium plasma ($n_e=5\mathrm{}\times {10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$) was heated by an intense ($\frac{\nu }{\gamma }\simeq 1$) relativistic electron beam (600 keV, 25-60 kA). Observations of the emitted line radiation and Thomson-scattered light indicate noncollisional electron heating rates consistent with electron-ion instability predictions, and total energy deposition consistent with electron-electron- instability saturation levels.