The effects of inelastic collisions on waves in partially ionized plasma

Abstract

An analytical description is presented for the excitation of electrostatic modes in partially ionized magnetized space and laboratory plasmas. The neutrals introduce some effects that are responsible for the creation of ions, which in a stationary plasma is balanced by a number of phenomena in which ions and electrons are lost. The behaviour of several modes is discussed, such as the ion acoustic, drift, ion cyclotron and the Farley–Buneman mode. The instability conditions are obtained, showing that inelastic collisions can either modify some of these modes or make them unstable. The formation of a global nonlinear structure in a spatially bounded laboratory plasma is discussed. The structure is experimentally observed, and an analytical model is presented showing that the charge exchange plays a decisive role in its formation.