Low-frequency potential structures in a nonuniform dusty magnetoplasma

The Linear and nonlinear properties of a modified convective cell (MCC) in a nonuniform dusty magnetoplasma with a perpendicular plasma flow are inves tigated. It is shown that the free energy of the equilibrium plasma flow ca n drive the MCC at nonthermal levels. By choosing some specific profiles fo r the sheared plasma flow and the dust number density, we analyze the eigen value equation for deducing the growth rate and the threshold of a convecti ve mode instability which arises due to its interaction with the shear plas ma flows. Our analytical results show that a Rayleigh-type instability sets in provided that the characteristic width of the flow does not exceed a ce rtain value. On the other hand, the nonlinear equation, which governs the d ynamics of the nonlinearly interacting convective modes, admits stationary solutions in the form of a vortex chain associated with zonal flows, as wel l as tripolar and global vortices. The relevance of our investigation to a laboratory experiment is discussed. (C) 2001 Elsevier Science B.V. All righ ts reserved.