The Langevin Equation and the A. C. Conductivity of Non-Maxwellian Plasmas

摘要

The use of the Langevin equation to describe the electrical conductivity of a non-Maxwellian plasma (a weekly ionized gas in which the average electron collision frequency is temperature dependent) may be in error unless it is understood that the dissipative term, g, is complex. In the limiting cases of either high or low pressures the imaginary part of g is negligible. The real and imaginary parts of g are evaluated for these limiting cases, for four different gases; air, helium, Maxwellian gas, water. The real part of g is shown to be the average collision frequency multipled by a numerical factor, the size of which depends on the nature of the gas and the pressure limit.