Derivation of paleoclassical key hypothesis

The paleoclassical model of radial electron heat transport in resistive, current-carrying toroidal plasmas is based on a key hypothesis-that electron guiding centers move and diffuse with radially localized annuli of poloidal magnetic flux. This hypothesis is shown to result from transforming the drift-kinetic-equation to poloidal flux coordinates in situations where this flux is governed by a diffusion equation and analyzing the mathematical characteristic curves (guiding center trajectories) of the resultant drift-kinetic equation on the magnetic field diffusion time scale tau(eta)equivalent to a(2)/6D(eta). These effects add a tau(eta) time-scale Fokker-Planck-type spatial diffusion operator to the drift-kinetic equation. (c) 2007 American Institute of Physics.