Nonlinear stationary vortices in gravitating fluid
The problem of nonlinear self-organization of perturbations in differentially rotating, nonuniform, gravitating systems is studied. Two types of stationary nonlinear solutions, in the form of tripolar vortices and vortex chains of gravitational potential and density, dependent on the spatial profiles of the basic state quantities, are found. They propagate with a constant velocity perpendicularly to the basic state gradients, and characteristic time scales for the creation of such vortical structures are shown to be much shorter than the corresponding intervals for gravitational contraction.
Tripolar vortex in plasma flow
Abstract Strongly nonlinear processes in a two-component plasma with sheared flow, in the low-frequency limit, in comparison with the ion gyro frequency Ωi, and for perturbations propagating perpendicularly to the ambient magnetic field are studied. In the linear domain such a system is prone to the development of instability of the Kelvin–Helmholtz type. In the nonlinear regime this instability can saturate into stationary travelling solutions of the form of vortex chains and tripolar vortices, which are found in this paper.
Drift waves in plasmas with sheared flows
In the standard approach to the problem of shear stabilization of drift waves the diamagnetic drift velocity v* is regarded as a constant, which is usually not satisfied at the edge of a tokamak plasma. In configurations of this type, with a steep density gradient and radially sheared transverse velocity field, the magnetic shear stabilization criteria are severely restricted, and the velocity profile curvature v0″(x) is found to play a crucial role. In the strongly nonlinear regime, unstable drift waves may saturate into stationary coherent vortex-type structures. The latter include a tripolar vortex.