Finite element modeling of a two-fluid RF plasma discharge

The design and understanding of plasma and its bounding sheath requires an effective modeling technique that is both adaptable to arbitrary geometry and time accurate. We present a finite-element-based model for two-fluid plasma. The continuity and momentum equations for electrons and ions are solved simultaneously with the Poisson equation, using an efficient subgrid-embedded algorithm. The model does not involve any conventional patching techniques at the plasma–sheath interface. The solutions are interpreted using the speed of ionization as one key parameter determining collisional sheath behavior. Numerical limitations are also analyzed from the theoretical derivation of solution amplification factor and phase velocity.