title: Neoclassical radial electric field and transport with finite orbits.
abstract: Neoclassical transport in a toroidal plasma with finite ion orbits is studied, including for the first time the self-consistent radial electric field. Using a low-noise deltaf particle simulation, we demonstrate that a deep electric-field well develops in a region with a steep density gradient, because of the self-collision-driven ion flux. We find that the electric field agrees with the standard neoclassical expression, when the toroidal rotation is zero, even for a steep density gradient. Ion thermal transport is modified by the electric-field well in a way which is consistent with the orbit squeezing effect, but smoothed by the finite orbits.
authors.affiliation: General Atomics, P.O. Box 85608, San Diego, California 92186, USA.
authors.forename: W X
authors.initials: WX
authors.lastname: Wang
authors.forename: F L
authors.initials: FL
authors.lastname: Hinton
authors.forename: S K
authors.initials: SK
authors.lastname: Wong