contains two reviews.
In the review by V.A. Rozhansky, the problem of currents and self-consistent electric fields in the magnetized fully ionized plasma is considered. The situation in fully ionized plasma is completely different from that in solid state, gases, or partially ionized plasmas, where the current density is proportional to the electric field. In contrast, in a fully ionized magnetized plasma, a homogeneous electric field causes drift both for electrons and ions, while a current in the direction of the electric
field is absent. A perpendicular current arises when the electric field is temporary or spatially dependent. Various mechanisms, when the perpendicular currents are driven by inertia, collisions with neutrals and different components of viscosity tensor are analyzed in the review. Current systems in a vicinity of a biased electrode are studied in connection with such applications as probes, unipolar arc formation, pellets, where two-dimensional or three-dimensional currents systems determine plasma dynamics, shielding properties, and current–voltage characteristics.
Since the end of 80th it became clear that self-consistent electric fields play the key role in the formation of improved confinement regimes (H-regimes) in tokamaks and stellarators. The poloidal drifts suppress the turbulence and hence the turbulent transport coefficients so that the transport barriers with steep density and temperature gradients and reduced transport coefficients are created. It is demonstrated that the electric field structure is consistent with the experimental observations.
In the second review "Correlations and anomalous transport models" by
O.G. Bakunin, numerous aspects of turbulent transport are considered. This review is intended to summarize the recent results from the ultidisciplinary field of anomalous diffusion in turbulent plasma. A description of turbulent transport in the presence of coherent structures, convective rolls, zonal flows, and stochastic magnetic fields is a very complex problem.
From the methodological point of view, this review focuses on the general use of correlation estimates, quasilinear equations, and continuous-time random walk approach. The structure of some derivations, when they may be useful for more general purposes, is given in detail. Thus, the review provides a fairly informative treatment of seed diffusion effects in the framework of the correlation description. The relationship between Lagrangian and Eulerian correlation functions is discussed, and the problem of relations between stochastic instability and transport effects in a stochastic magnetic field is analyzed.
The author reviews in details the percolation approach to turbulent transport. Both the monoscale representation and multiscale approach are considered. The relationships between the transport and correlation exponents are derived. Nonlocal and memory effects in the framework of the continuous-time random walk model are treated
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В продаже с 21.01.2023
