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

Abstract

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.

Vacuum Circuit Breaker Postarc Current Modelling Based on the Theory of Langmuir Probes

“…The previously stated problems lead to the conclusion that the postarc current model needs to be revised. Since we are mainly interested in the interaction of the breaker with the circuit, we try to avoid the complicated physics of plasma-sheath dynamics, and hence their considerable numerical efforts to solve the plasma equations, of which numerous examples can be found in the literature [15]- [17]. To summarize, the model should meet the following requirements: 1) numerically stable; 2) easy to solve; 3) easy to apply in any electrical circuit; 4) simulate the vacuum postarc's electrical behavior; 5) require a short list of parameters.…”