Collins, GA, Durance, G, Hogg, GR, Tendys, J & Watterson, PA 1988, 'Small aspect ratio tokamak configurations generated by rotating magnetic field current drive', Nuclear Fusion, vol. 28, no. 2, pp. 255-266.
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Small aspect ratio tokamak configurations are produced by adding a toroidal magnetic field to the rotamak. Configurations with toroidal fields ranging up to 200 G at the magnetic axis are studied. Typical parameters are Itor 2 kA, Bpoi 50 G, q0 1-3, ne (peak) 1019 m-3Te 12 eV, τp 15 μs and τe 5μs for an RF input power of 40 kW. Most features of these configurations can be modelled by an MHD equilibrium code. The presence of the toroidal field is observed to have a significant influence on the rotating magnetic field current drive mechanism. © 1988 IOP Publishing Ltd.
Watterson, PA 1988, 'Analytical solutions for the current driven by a rotating magnetic field in a cylindrical plasma with azimuthal field', Journal of Plasma Physics, vol. 40, no. 1, pp. 109-126.
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The generation of steady currents by a rotating magnetic field (RMF) in a cylindrical plasma permeated by a steady azimuthal (or toroidal) magnetic field is studied analytically. Solutions are presented for the following limiting cases:(1) high resistivity, when the penetration of the RMF and current drive are confined to a skin depth layer;(2) low resistivity and weak toroidal field (small compared with the RMF), when the RMF fully penetrates the plasma and the toroidal current is that due to nearly synchronous rotation of the electron fluid with the RMF;(3) low resistivity and intermediate toroidal field (comparable to the axial field associated with synchronous current), when the toroidal current is a significant fraction of its synchronous value, but large oscillating fields are generated; and(4) strong toroidal field, when the RMF fully penetrates the plasma but current is only driven in a boundary layer at the plasma edge.The applicability of these solutions is governed by the relative sizes of three dimensionless parameters.
