Nonlinear Evolution of Non-axisymmetric Dynamical Instability in a Slender Accretion Torus

摘要

The nonlinear evolution of non-axisymmetric dynamical instability has been interpreted here wuhin the framework of soliton theory.The dispersion relation of a two-dimensional slender accretion torus in the long wavelength incompressible limit is similar to that of the linearized KdV equation.We argue that the ’planet-like’ solutions of nonlinear dynamical instability in the numerical simulations should he the soliton solutions of KdV equation.We also find that the vorticity of accretion disk is a non-conservation quantity due to the variation of density and entropy in the nonlinear evolution of dynamical instability It is the cause of the redistribution of angular momentum during the instability.