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P: Plasmaphysik

P 3: Low Temperature Plasmas, Plasma Technology

P 3.4: Talk

Monday, March 17, 2003, 16:45–17:05, FO4

Effective Plasma Bulk Boundary Conditions Derived from a Sheath Model — •Ralf Peter Brinkmann — Lehrstuhl für Theoretische Elektrotechnik, Ruhr-Universität Bochum

The numerical simulation of low pressure high density plasmas is inherently complicated due to the presence of vastly different length scales in the dynamics. Particularly, the sheath thickness H (which typically amounts to a few Debye lengths) is often much smaller than the reactor dimension L. This fact has motivated to apply the technique of matched asymptotic expansions to arrive at, effectively, a plasma description which matches a geometrically extended bulk model to an infinively thin sheath model. The presented contribution studies the valitiy of this expansion approach in the limit where H/L → 1, i.e., in a situation where the underlying assumption breaks down. Using a semi-analytical sheath model, boundary conditions are established which enable a leading-order representation of the appearing deviations. A numerical study is given to facilitate a quantitative comparison with more conventional approaches. It is confirmed that the novel boundary conditions lead indeed to a superior convergence behavior.