Plasma Heating by an Intense Electron Beam

An intense pulsed electron beam ($\frac{\nu }{\gamma }\sim 2$) was used to heat electrons in a target plasma in a magnetic field. A strong beam-plasma interaction was observed. Measured heating levels were found to be consistent with a two-stream instability calculation and return-current heating estimates. Energetic counter-streaming electrons were detected in the plasma during the beam pulse and possible sources of these electrons are suggested.