Unmagnetized sheath waves

Abstract

Plasmas bounded with metal walls have sheaths at their edges near the walls, along which electrostatic waves may propagate. We build on a long history of dielectric-bounded plasma waves, e.g., relating transverse (or series) resonances to cut-off frequencies of our sheath waves. We present kinetic simulations (PIC-MCC), confirming the dispersions and that the edge waves perturbed densities and potentials are largest at the edge; those of the body waves are largest in the body, all as if the two sets of waves are guided along their respective regions.

We also drive edge waves sufficiently strongly to cause electron heating producing ionization of the background gas, which maintains a plasma discharge. The heating profiles and density scaling of these resonant surface wave discharges differ markedly from the well known capacitive, inductive, and wave-coupled discharges.