The ion thermal conductivity for a pure Tokamak plasma

The ion thermal conductivity was calculated for a wide range of aspect ratios and collision frequencies by solving the drift kinetic equation, with a model collision operator, using a finite element method, and then calculating the energy weighted friction force to determine the heat flux. The thermal conductivity, determined from the heat flux was then curve fitted to analytic formulas. These formulas allow the conductivity to be calculated at all collision frequencies and aspect ratios down to about 3. The two main results of these calculations are, first, energy scattering increases the thermal conductivity, over values previously calculated, by a factor on the order of 1.5-2 and second, the Pfirsch-Schluter contribution becomes significant at low collision frequencies, when the aspect ratio is small. Comparisons of the thermal conductivity with the results of previous authors are given. The distribution function for various collision frequencies, aspect ratios and collision operators is included.