Kinetic effects in spherical gravitating systems

The kinetic processes of collisional evolution in anisotropic spherical gravitating systems are considered. A generalization of the classical formula for the relaxation time in anisotropic gravitating media is derived in the Fokker-Planck-Landau approximation. It is shown for gravitating stellar systems that the larger the degree of their anisotropy, the higher the rate of relaxation processes. In particular, for spherical systems with nearly radial orbits, the characteristic times of these processes can be comparable to the crossing time. The results obtained can be of interest for a great variety of problems in the dynamics of gravitating systems, for example, in the problems of stability for various models of gravitating systems, in investigating the dynamics of young star clusters at early stages of their evolution, the dynamical evolution and stability of highly flattened galactic disks, in the problems of the distribution of stars around a black hole, and in a number of other problems.