Anomalous Diffusion of Plasma Current and Anomalous Transports Induced by Plasma Turbulence

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Heat and particle transports which are associated with the helicity transport are obtained in a current-carrying plasma. The helicity flux represents the transport of parallel current density and is produced by an electric field with a circularly polarized component. Fluctuations with circularly polarized components induce finite average in cross-field nonlinear parallel current, which leads to generation of frictional electron heat flux as well as ion nonlinear polarization current which produces particle flux. The circular polarization of the perturbed electric field thus relates the helicity flux, electron heat flux and the particle flux in such a manner that the heat and the particle transports in the direction opposite to the helicity flux. This result applies whether the helicity is injected externally by oscillating fields or it is generated internally in the plasma.In the magnetohydrodynamic relaxation accompanying fast reconnections, magnetic fluctuations originating from kink-type instabilities yield a finite magnetic compression, and the corresponding transverse electric field is dissipated through the transit-time damping. This dissipation mechanism does not change the helicity, while it dissipates the fluctuation energy to result in direct heating of ions. This is in contrast to a slow relaxation process based on the tearing mode turbulence, where the parallel electric field is predominantly dissipated, which accompanies preferential heating of electrons and dissipation of the helicity.