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

在载流等离子体中得到了与螺旋度输运有关的热和粒子输运。螺旋度通量表示平行电流密度的输运，是由具有圆极化分量的电场产生的。圆极化分量的涨落引起跨场非线性平行电流的有限平均，从而产生摩擦电子热流和离子非线性极化电流，从而产生粒子通量。因此，扰动电场的圆极化以这样的方式将螺旋度通量、电子热通量和粒子通量联系在一起，使得热和粒子沿与螺旋度通量相反的方向传输。无论螺旋度是由振荡场从外部注入还是在等离子体内部产生，这一结果都适用。在伴随快速重联的磁流体弛豫中，由扭结型不稳定性引起的磁涨落产生有限的磁压缩，相应的横向电场通过渡越时间衰减而耗散。这种耗散机制并没有改变螺旋度，而是耗散了涨落能量，从而导致离子的直接加热。这与基于撕裂模湍流的缓慢弛豫过程相反，在撕裂模湍流中，平行电场主要被耗散，它伴随着电子的优先加热和螺旋度的耗散。

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.