Role of magnetic shear in flow shear suppression

Abstract

The interplay between flow shear and magnetic shear is studied in the three-dimensional reduced magnetohydrodynamic turbulence. It is analytically shown that near the resonance surface, transport quenching by flow shear is weakened by magnetic shear as the latter interferes with shearing process. In particular, anomalous particle transport becomes more efficient in the regime with stronger magnetic shear for a given flow shear while self-regulation of zonal flows becomes less effective. The results suggest that weak magnetic shear could be favorable for the formation of transport barrier. © 2007 American Institute of Physics.