| The effects of the ion sheath on the RF properties of conductors in an isotropic plasma are investigated.;This model is applied to the spherical probe in order to calculate its admittance. At low frequency, the probe displays a non-zero conductance which agrees with the predictions of kinetic theory.;The model is also applied to an infinite conducting cylinder in order to study surface waves. The sheath wave dispersion is found to be very sensitive to the sheath density profile. These results invalidate the use of a vacuum sheath except for very low frequency and high negative bias. A new class of waves, named presheath waves, is found also to propagate along the wire.;Experimentally, the sheath wave mode is studied and found to be very well described by this new sheath model. Presheath waves are also observed and found consistent with the theoretical predictions.;A warm plasma model of the sheath is developed. The sheath is made of one or several regions of uniform plasma density. A consistent set of boundary conditions is developed from hydrodynamic theory. The absorptive boundary condition is used at the conductor-plasma interface. |
