Transport matrix and electric field formation in stochastic magnetic field

The anomalous transport of high-temperature plasma in the region of a stochastic magnetic field line is studied. Plasmas in toroidal systems such as tokamaks are considered. The plasma transport matrix in the stochastic region is derived, with the assumption of a quasilinear approximation for the diffusivity of the magnetic field line, D_M. By use of this transport matrix, the radial electric field formation and the associated temperature distribution in the stochastic region are obtained. The magnitude of radial electric field is found to depend on the value of D_M and on the heat fluxes and temperatures of electrons and ions in the nonstochastic region. The buildup of the radial electric field, in turn, affects the transport coefficients as well as the temperature gradients in that region.