Stability of toroidal drift-type waves in the presence of a velocity field

The instability associated with the toroidal drift-type wave is shown to be stabilized by a radially varying equilibrium poloidal velocity field of suitable magnitude and curvature. The radial mode envelope is now much more extended than its conventional localized Gaussian form. The role of velocity curvature (V(r)θdouble-prime) is found to have robust effects on the stability and radial structure of the mode. Velocity shear (V(r)θ') on the other hand is found to have a rather insignificant role in this matter. copyright 1995 American Institute of Physics