Suppression of Rayleigh-Taylor instability by flow curvature

The question of whether it is the shear [V(r)'] or the curvature [V(r)''] in the flow profile [V(r)] which plays the dominant role in suppressing the low-frequency (omega < omega(i), where omega(i) is the ion gyrofrequency) instabilities and fluctuations is investigated. Rayleigh-Taylor (RT) instability is considered in this work. The role of flow curvature is found to have a robust effect on the stability and on the radial structure of the mode. For a positive value in the flow curvature RT is suppressed whereas a negative flow curvature excites the mode. Flow shear, on the other hand, plays an insignificant role in this matter. These theoretical findings are in agreement with the recent experimental results. (C) 1997 American Institute of Physics.