Electron density fluctuations in a plasma with collision frequency proportional to speed

The collective fluctuation spectrum of the electron density in a plasma is calculated by a new method which has been developed in an earlier paper (Theimer, Hicks and Behl, 1977). The method is applied to partially ionized plasmas with collision frequency vsub(e)(v) = av proportional to the speed of the electrons. The general formulas for the fluctuation spectrum are numerically evaluated and show that the sharp resonance peak near the electron plasma frequency is very sensitive to the speed dependence of vsub(e): the peak is only moderately broadened if the collision parameter ysub(e) is constant and of the order 0.1; however, it is practically washed out if ysub(e) is proportional to v while still being of the order 0.1 in the average. Conditions under which this effect may be observed are discussed. (author)