Modeling low pressure collisional plasma sheath with space-charge effect

The present work develops a computationally efficient one-dimensional subgrid embedded finite element formulation for plasma-sheath dynamics. The model incorporates space-charge effect throughout the whole plasma and the sheath region using multifluid equations. Secondary electron emission is not considered. A third-order temperature dependent polynomial is used to self-consistently calculate the rate of ionization in the plasma dynamic equations. The applications include dc and rf sheath inside a glow discharge tube where the noble gas is immobile, and a partially ionized plasma sheath inside an electric propulsion thruster channel in which the gas flows. The electron and ion number densities of the numerical solution decrease in the sheath region as expected. The ion velocity and electron temperature profiles also exhibit the expected behavior. The computed sheath potential compares well with the available experimental data.

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