Suppression of cross-field turbulent transport of passive scalar concentration in two dimensional magnetohydrodynamics

A theory of the cross-field turbulent transport of a passive scalar in a magnetized, two dimensional, electrically conducting fluid is presented. Both a renormalized quasilinear calculation and analyses of an exactly solvable simple model demonstrate that weak magnetic fields in a highly conducting medium are capable of strongly suppressing the turbulent cross-field transport by alteration of the Lagrangian correlation time of a scalar fluid element, without effect on the turbulence intensity. Passive scalar transport along the magnetic field is unchanged. An explicit expression for the effective cross-field diffusivity is given. {copyright} {ital 1997} {ital The American Physical Society}