General method describing self-similar regimes of nonstationary disc accretion. A possibility of self-organization

Abstract

The hydrodinamic equations are used as a method of modelling nonstationary accretion discs. The obtained model equations are nonlinear and may be resolved with the help of numerical methods or by theoretical group methods. This work is based on model equation obtained under the assumption that viscosity and opacity laws are power functions of the local accretion disc parameters. The obtained self-similar solution provides a possibility of finding self-similar solutions from first and second gandre in dependence on the problem formulation. It is shown that if the accretiondisc mass varies with time resulting from secondary component flux variation, then the viscosity has apparent time dependence. The shape of this dependence in function of varying external flux is given. Using this result a criterion of self-organization occurence of quasi stationary toroidal type is given for the disc. © 1988.