A simple neoclassical point model for transport and scaling in EBT

Abstract

A simple neoclassical point model is presented for the ELMO Bump¥ Torus experiment. Solutions for steady state are derived. Comparison with experimental observations is made and reasonable agreement is obtained. * Work supported by Energy Research and Development Administration under Contract W-7405-eng-26 with Union Carbide Corporation, Contract EY-76-C-03-0167, Project 38 with General Atomic Company, and Contr~ct AT-04-3-1018 with Science Applications, Incorporat~d.

Effects of positive potential in the catastrophe theory study of the point model for bumpy tori

“…2.1. Dimensionless transport equations Introducing dimensionless EBT units specified in Punjabi & Vahala (1983), the point model equations for neoclassical non-resonant ions with E r >0 are given by…”

“…This leads to consideration of neoclassical non-resonant ion transport rather than neoclassical non-resonant electron transport. To facilitate comparison with our earlier work (Punjabi & Vahala 1983) we present most of our results under the assumption that the particle and energy confinement times are equal to each other, even in the regime E r > 0. Thus we are assuming that the particle and energy confinement times are all reduced by the same factor (mjm^ compared with the confinement times appropriate in the non-resonant electron regime of E r < 0.…”

“…Recently (Vahala, Punjabi & Harris 1982;Punjabi & Vahala 1983) we applied ideas of catastrophe theory to a point model for bumpy tori, assuming the ambipolar electric potential to be negative. This results in neoclassical non-resonant electron transport loss, with the basic confinement time set by these nonresonant electrons.…”

“…In this paper we modify the EBT point model of Hedrick et al (1977) to include both ICRH and positive potential, E r > 0. This leads to consideration of neoclassical non-resonant ion transport rather than neoclassical non-resonant electron transport.…”

“…The effect of ICRH on the fold structure of the equilibria is considered in § 4, assuming equal particle and energy confinement times, r E = r n . This assumption is made so as to allow comparison with the case of negative potential, E r < 0, with neoclassical non-resonant electrons which was considered previously (Punjabi & Vahala 1983). However, Hedrick (1983) and Chang & Miller (1983) have shown that in general, ioTE r > 0, the energy confinement time is less than the particle confinement time.…”