On instability of three-dimensional dynamic equilibrium states of self-gravitating Vlasov-Poisson gas

Abstract

The Vlasov-Poisson kinetic equations describe the dynamics of point masses in a self-consistent gravitational field. For example, these equations describe clusters of stars, galaxies or interstellar gas, large-scale processes in the Universe. For stationary solutions to the Vlasov-Poisson kinetic equations, a sufficient stability condition has already been obtained previously. However, it has not been conversed until now (neither for small perturbations, nor, especially, for finite ones). The Vlasov-Poisson kinetic equations are related to equations of hydrodynamic type, for which, in turn, there are methods for conversing sufficient stability conditions (at least, in the linear approximation). In this paper, absolute instability for spatial dynamic equilibrium states of Vlasov-Poisson gas with respect to small three-dimensional (3D) perturbations will be proved by the direct Lyapunov method.