Effects of Collisions on Electron Density Fluctuations in Plasmas

The spectrum of electron density fluctuations has previously been calculated for a collisionless plasma. In this paper, the theory is extended to include collisions as represented by a Fokker-Planck equation such as the one used in the theory of Brownian motion. Numerical calculations have been carried out to show graphically the transition of the spectrum from the collisionless to the collision-dominated case. The results of the present analysis involve some thus far untabulated functions. These functions have been numerically evaluated and the results are presented in graphical form.