Two-dimensional dynamics of two-component plasma with finite β

The collisionless two-dimensional dynamics of a two-component plasma, where the fast ions determine the plasma pressure and the cold ions determine the plasma inertia, is studied both analytically and numerically. The fast ion Larmor radius is assumed to be of the order of the plasma transverse size. The set of equations for such a plasma is obtained, taking into account small but finite plasma pressure (β≪1). It is shown that, in the limit of high cold component density, the dynamics studied in this paper is qualitatively similar to Euler two-dimensional hydrodynamics. The existence of an instability due to nonuniform gradient drift is shown. This instability is similar to the Rayleigh instability in hydrodynamics and the diocotron instability in a nonneutral plasma. Some analytical samples of eigen modes are presented. The stability of axisymmetric equilibrium with a monotone profile of the guiding center density is proved. The ensemble of the large Larmor radius ions with conserved magnetic moments has a potential energy, which reduces when the spatial distribution of the guiding centers becomes more compact. The transformation of this energy to the kinetic energy of E×B turbulence is accompanied by self-localization of the fast ion spatial distribution, which is demonstrated by the numerical simulation.