Leaky-box approximation to the fractional diffusion model of cosmic rays

Two models of anomalous diffusion of cosmic ray in the leaky-box approximation are compared: one of them is based on the decoupled time-space L'evy flights and the other on fractional walks with a finite free motion velocity. Distributions of first passage time and paths are computed and evolution of diffusion packets to equilibrium state is shown. Calculations demonstrate essential difference between the two models: the coupled scheme gives more realistic results.