Anomalous plasma particle transport due to low-frequency perturbations in the edge region of the nuclear fusion toroidal devices in the crossed electric and magnetic fields is investigated now intensively (see, for example, [1]).
In turbulence of small amplitudes the electron trajectories are stochastic. At achievement of the large amplitudes when frequency of the electron oscillations in the vortical convective cell of the perturbation exceeds the growth rate of its excitation the vortical cell changes in its vicinity the electron density gradient ∇n_e, which strengthens the next vortical cells. Thus on the vortical cell boundaries the jumps of n_e(r) arise. On these jumps the growth rates of the next vortical cell excitation are much more than the growth rate, determined by not perturbed ∇n_e. Thus, ordering of cells arises similar investigated in [2]. It provides faster electron transport. In other words, the selfconsistent excitation of the low-frequency convective cells in the nonequilibrium plasma, drifting in crossed electric and magnetic fields in nuclear fusion devices, by a radial gradient of density is unstable concerning occurrence of correlations. Thus convective-diffusion radial particle transport and partly ordered lattice of vortical convective cells in space (r, z) arise. The perturbations of lattice electron bunches reflect resonant electrons. The perturbations of lattice electron holes trap resonant electrons. The convective-diffusion equation, describing these convective-diffusion radial dynamics of the electrons has been derived.
It has been shown, that in the plasma, drifting in crossed electric and magnetic fields in nuclear fusion devices, two kinds of vortical perturbations, strongly distinguished on properties, are excited: not moving and quickly moving vortical convective cells. The spatial structures of these not moving and quickly moving convective cells have been constructed. It has been shown, that the radial dimensions of these convective cells depend on their amplitudes and essentially depend on a radial gradient of density and magnetic field.
It has been shown, that the observed fingers of density in peripheral area may be explained by the formation of these convective cells.
The dispersion equation, describing the excitation of the perturbations in collisional plasma of nuclear fusion devices, drifting in the crossed electric and magnetic fields, has been derived. It has been shown, that there is the universal parameter, controlling the excitation of these perturbations. It has been obtained, that at the certain values of the system, determined by this parameter, the excitation of these perturbations is suppressed. Certainly, in this case the anomalous radial transport is suppressed.

References