The characteristics of RF modulated plasma boundary sheaths: An analysis of the standard sheath model

The characteristics of radio frequency (RF) modulated plasma boundary sheaths are studied on the basis of the so-called ``standard sheath model.'' This model assumes that the applied radio frequency $\omega_{\rm RF}$ is larger than the plasma frequency of the ions but smaller than that of the electrons. It comprises a phase-averaged ion model -- consisting of an equation of continuity (with ionization neglected) and an equation of motion (with collisional ion-neutral interaction taken into account) -- a phase-resolved electron model -- consisting of an equation of continuity and the assumption of Boltzmann equilibrium --, and Poisson's equation for the electrical field. Previous investigations have studied the standard sheath model under additional approximations, most notably the assumption of a step-like electron front [1]. This contribution presents an investigation and parameter study of the standard sheath model which avoids any further assumptions. The resulting density profiles and overall charge-voltage characteristics are compared with those of the step-model based theories. \\[4pt] [1] V.A.~Godyak and Z.K.~Ghanna, \emph{Sov.~J.~Plasma Phys.} \textbf{6}, 372 (1979)