Relation between beam driven seed current and rotation in a steady state field reversed configuration

The rotation induced in a beam driven, steady state field reversed configuration is investigated for cases with or without multipole magnetic fields. When no magnetic field is present, the back-current can be inhibited by the Ohkawa effect if the charge number of the beam is less than the effective charge number of the background ions. However, the resulting rotation of the plasma often leads to instabilities. For systems with a large bootstrap effect, the rotation can be moderate, but it is then difficult to contain the fusion products. An additional problem is that the Ohkawa effect due to alpha particles tends to destroy the equilibrium. Previously, it was shown that the presence of a quadrupole field inhibits the formation of a back-current. It is shown that a steady state flux can be maintained with a moderate input power, with the resulting rotation being slow enough so that the conditions of stability are given. The study has been performed for reactor grade and experimental parameters. Means to supply a continuous source of particles and additional energy will have to be devised. (author). 17 refs, 3 figs, 1 tab