A two-dimensional vortex subjected to shear flow is considered in Rayleigh-
Taylor mode of magnetized plasmas. It is shown that, when vortex-flow is al
most absent, linear instability is suppressed due to shear-flow. In the pre
sence of a vortex, however, there is a possibility of secondary instability
excitation. It is demonstrated that the efficiency of this secondary insta
bility depends on the sense of rotation and strength of vortex-flow and she
ar-flow. (C) 2000 American Institute of Physics. [S1070-664X(00)04609-7].