Current Drive in Recombining Plasma
Authors: P.F. Schmit and N.J. Fisch
Abstract:
The Langevin equations describing the average collisional dynamics of suprathermal particles in
nonstationary plasma remarkably admit an exact analytical solution in the case of recombining
plasma. The current density produced by arbitrary particle fluxes is derived including the effect
of charge recombination. Since recombination has the effect of lowering the charge density of the
plasma, thus reducing the charged particle collisional frequencies, the evolution of the current density
can be modified substantially compared to plasma with fixed charge density. The current drive
efficiency is derived and optimized for discrete and continuous pulses of current, leading to the
discovery of a nonzero "residual" current density that persists indefinitely under certain conditions,
a feature not present in stationary plasmas.
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Submitted to: Physics of Plasmas (August 2011)
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Download PPPL-4654 (pdf 718 KB 11 pp)
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