Transport properties of MHD-generator plasmas

The kinetic theory of partially ionized plasmas is applied to the calculation of transport properties for plasma conditions representative of MHD generators. Emphasis is placed on the accuracy of approximate formulas in comparision with the exact values. The exact values are obtained by means of spherical-harmonic expansions of the electron and heavy-particle Boltzmann equations, with the use of simplifications associated with the small electron mass. Consideration is given to both electron and heavy-particle properties in the presence of a magnetic field, including electrical and thermal conductivity, thermal diffusion and viscosity coefficients and allowing for differences between the electron and heavy-particle temperatures. In all cases it is found that accurate results can be obtained by simpler means than the classical Chapman-Enskog calculation, but that various approximate formulas differ significantly in their accuracy. Several new formulas are proposed. The influence on these results of differing cross sections is discussed, as are the effects of nonelastic collisions in the electron energy equation and the difference between quasi-scalar properties in a magnetic field and those that apply in the absence of or in the direction parallel to a magnetic field. Corrections to the calculations when the plasma parameter ln Λ is not large are considered.