Kinetic Effects on the Convective Plasma Diffusion and the Heat Transport

Cross field heat and particle transport due to the thermally excited convective cell mode is investigated both by theoretical work and by particle simulations. It is shown that there is a parameter range where the heat diffusion coefficient D H is considerably less than the particle diffusion coefficient D P . This results from the fact that high energy particles in a velocity distribution diffuse much more slowly than the low energy particles because the fluctuating electric fields are averaged over their finite Larmor radii. The magnetic field scaling of D H / D P is also discussed. The results imply that ions in a thermonuclear reactor should be less affected by turbulence than are electrons as appears to be the case.