ISSN:
1089-7674
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A long mean free path, small Larmor radius expansion of the coupled Fokker–Planck equations for ions and electrons is performed for a steady-state, axisymmetric, Ohmically driven tokamak with small energy sources. The expansion is different from, but related to, the secondary long mean free expansion of the usual neoclassical transport theories. Two scalings of loop voltage are proposed, where the ratio of the Ohmic current to the bootstrap current is either of order one, or large. The second scaling is presently more appropriate. The expansion of the kinetic equations can be carried to all orders, and there are four equations for the four lowest order profile functions n(ψ), Ti(ψ), Te(ψ), and φ(ψ). For comparable Ohmic and bootstrap currents Ti(ψ)=Te(ψ). For larger loop voltage the temperature difference may be nonzero, depending on the necessary energy sinks. The electron energy flux is calculated and scales differently from neoclassical theory giving much larger transport. The energy confinement time varies in magnitude, depending on the loop voltage and the energy sinks. Values comparable with present experiments appear possible. © 1994 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.870867
Permalink
