Velocity shear effect on Rayleigh-Taylor vortices in nonuniform magnetized plasmas

Abstract

In this paper, the effect of velocity shear on Rayleigh-Taylor vortices has been demonstrated. An inhomogeneous plasma is considered with a density profile such that the diamagnetic drift velocity V_n=(cT_e/eB)dn₀/dx is a constant and includes the effect of an ambient poloidal shear flow V_eq(x)=V_⊥0'(x-x₀)y. The final equation describing the stationary Rayleigh-Taylor vortex is shown to have the structure of a nonlinear Poisson equation, where the nonlinearity arises essentially because of the velocity shear term. This equation has been solved numerically and it has been shown that qualitatively new two-dimensional monopole vortex solutions may be obtained in the appropriate parameter space. Therefore, a new important nonlinear effect related to equilibrium shear flow has been identified in the calculations of Rayleigh-Taylor vortices which results in monopole-like solutions in plasmas.