Ion Heating Due to Double-Layer Disruption in a Plasma

Abstract
A new mechanism is presented for ion heating in a plasma penetrated by an electron beam. Oscillating potentials comparable to the electron-beam energy are observed below the threshold of the stable double-layer formation. These fluctuations (formation and disruption of double layers) accelerate, trap, and detrap thermal ions, resulting in highly energetic ion bursts, which form a tail on the ion-energy distribution function.