Effect of Finite Beta on Drift-Wave Turbulence and Particle Confinement

This Letter predicts, on the basis of the structure of mode-coupling equations, that if the plasma $\beta$ exceeds the square of the inverse aspect ratio, ${\left(\frac{a}{R}\right)}^2$, the cross-magnetic-field diffusion is greatly enhanced by the appearance of convective cells even in the presence of magnetic shear.