When a radio-frequency plane wave is incident upon an inhomogeneous, lossy plasma slab, part of the electromagnetic energy is reflected, part is absorbed by the plasma medium, and part is transmitted. At sufficiently high power levels (about 1 watt cm2 at X-band frequencies), the equation of state of the plasma is altered, which produces a change in the effective dielectric constant of the medium. In the high-frequency limit, the effective dielectric constant of the medium is expressed as a function of the electron density and an effective collision frequency. The electron density and effective collision frequency at each point in the medium are functions of the electron temperature. In Part I, the electron temperature (Te) at each point (z) in the slab has been expressed in terms of the local value of E2/ω2, where E = electric field amplitude and ω = signal frequency, i.e., Te = Te(z, E2/ω2). Using the predetermined functional dependence of Te on z and E2/ω2, the electromagnetic field distribution and the net reflection and transmission coefficients of the plasma slab are computed by employing the Runge–Kutta technique to integrate Maxwell's equations numerically step by step. For each value of ω, relatively small changes in the reflection and transmission coefficient are produced as [Formula: see text] is increased up to a critical value of [Formula: see text], where Einc = incident electric field amplitude. For values of [Formula: see text] greater than this critical value, there is a sharp increase in the reflection coefficient and a sharp drop in the transmission coefficient.
Estimating Effective Collision Frequency and Kinetic Entropy Uncertainty in Particle-in-Cell Simulations
