Nonlinear evolution of double layers and electron vortices in an unstable plasma diode

Abstract

Nonlinear evolution of a large-amplitude relaxation oscillation in an unstable plasma diode is investigated by a computer simulation using a particle model. The oscillation is closely related to double-layer dynamics accompanied by a negative potential dip on the low-potential tail. A vortex is formed in the electron velocity phase space during the potential evolution, which causes a topological rearrangement of the phase space in the high-potential plasma.