Effects of a Velocity-Dependent Collision Frequency on Wave-Plasma Interactions

Two parameters, an effective collision frequency and an effective plasma frequency, are introduced to describe the effects of the velocity dependence of the collision frequency on wave-plasma interactions. Although mathematically related to other parameters previously used, this particular choice has the decided advantage of providing physical insight into the effect of the collision frequency variation. These parameters are calculated from actual cross section data for He, Ne, A, and N2. A discussion is also given of the effect of the velocity dependence of the collision frequency on the electron cyclotron line shape in magnetoplasmas. The introduction of these effective parameters provides a means for understanding the non-Lorentzian line shapes obtained from exact calculations of the absorption coefficients.