The Time Evolution Effects in Fermi Acceleration by Shock Waves (Ⅲ)

In this paper, a study of the time evolution processes of Fermi acceleration by shock waves in the case of the diffusion coefficient of particles varies with momentum is made. The evolution of the energy spectra and the kinetic energy of accelerated particles with various temporal and spacial distributions of source particles are obtained. The results of calculation show that the energetic particles are not as easy to be accelerated as comparied with the case of the diffusion coefficient independent on momentum. The average kinetic energy increases with time according to the law of-t^2/n, provided that the diffusion coefficitnt varies with the momentum in the form of x-Pⁿ.