KINETIC-THEORY OF PROPAGATION AND RUNAWAY GALACTIC COSMIC-RAYS .2. SELF-CONSISTENT MODEL

Nonlinear kinetic equations describing cosmic ray propagation in a sca ttering medium are analyzed. The scattering is determined by cosmic ra y interaction with MHD-fluctuations. We consider a self-consistent mod el in the framework of MHD-wave excitation by the cosmic rays. Our inv estigations show that in the model the region in which cosmic rays are confined occurs naturally around the disk of cosmic ray sources if th e particle energy is sufficiently small (less than 10(8) GeV for some model parameters). At the boundary the scattering is not effective giv ing rise to the runaway flux of cosmic rays. We define this region as the cosmic ray halo of the Galaxy. For higher particle energies the co smic ray flux is not able to produce the MHD-turbulence needed for par ticle scattering and these particles freely leak out from the Galaxy. In the region of low energies the convective transport of particles in the halo may be important. However the runaway flux also arises at th e boundary of the halo in this case.