On the temporal development of a plasma sheath

Abstract

In this work we study a one-dimensional model for the time-dependent behaviour caused by placing an uncharged conducting surface in contact with a uniform equilibrium plasma. Both the probe potential and plasma response are unknown a priori but are specified through a set of self-consistent model equations and boundary conditions. We investigate some numerical and analytical consequences of this model. In particular, we consider such issues as (i) the formation and expansion of a quasi-neutral region connecting the non-neutral sheath to the distant undisturbed plasma; (ii) the validity of assuming the existence of a sheath edge; and (iii) the role of both static and dynamic Bohm criteria in the theory of unsteady sheath development.