Boundary conditions and numerical fluid modelling of time-evolutionary plasma sheaths

The fluid equations for a one-dimensional, unmagnetized and collisionless plasma are numerically integrated in a finite domain to obtain sheaths at the absorbing wall system boundaries. The type of boundary conditions required for the formation of and for sustaining the long-time evolution of sheaths is discussed in detail. In contrast to earlier specialized fluid approaches, this treatment utilizes a more general fully non-linear fluid model, incorporating both ion and electron dynamics, to generate time evolutionary sheaths. In particular, we avoid restrictions such as the use of Boltzmann distributions for one or more components, the use of an artificial two-section plasma fluid model or the use of the quasi-neutrality assumption.