Analytic model of near-field radio-frequency sheaths. II. Full plasma dielectric

An analytic model is derived for electromagnetic radio-frequency (rf) wave propagation in a plasma-filled waveguide with rf sheath boundary conditions. The model gives a simplified description of the rf fields and sheath potentials near an ion cyclotron range of frequencies antenna under certain conditions. The present work lifts the restriction to a low density plasma ('tenuous plasma model') described in a previous paper [D. A. D'Ippolito and J. R. Myra, Phys. Plasmas 16, 022506 (2009)] to include the full plasma dielectric tensor with the ordering εperpendicular∼εx∼1, ε||>>1 for the case where the magnetic field is well aligned with the antenna. It is shown that retaining εx∼1 provides an additional drive term for the rf sheath. This effect is shown to be negligible in most practical situations suggesting that the tenuous plasma model does not miss any essential finite-density effects. The condition to recover the tenuous plasma result is derived. Expressions for the sheath voltage and sheath power dissipation are given in the arbitrary density limit, and a comparison of several mechanisms for dissipating power in rf sheaths is discussed.