Diffusion approximation of the kinetic equation for the cosmic ray particles distribution function

The charged particle propagation in an irregular magnetic field is investigated. The kinetic equation was used for the mean particle distribution function in an array of random magnetic fields. The interaction of particles with a random magnetic field is specified by the collision integral and the correlation tensor of the random magnetic field. The diffusion approximation is calculated of the kinetic equation in case of particle propagation in a strong magnetic field of interplanetary space, i.e., the particles are specified by helical motion in space. (author)