Theory of a double sheath between two plasmas

Abstract

A model of a double sheath between two plasmas is presented in which reflected particles and the initial velocities of accelerated particles are considered. The model shows that, in addition to the voltage drop across the double sheath, the ions from the plasma sac acquire kinetic energy (comparable with the electron thermal energy) in a presheath region. The ratio of the ion and electron current densities can depart significantly from Langmuir’s ( m / M ) ½ .