|Budget Amount *help
¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1999 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1998 : ¥900,000 (Direct Cost : ¥900,000)
We are constructing the realistic model of the cosmic ray propagation in the Galaxy.
Taking the picture that cosmic rays are propagating, scattered by the galactic magnetic field, two approaches are taken. One is called 'Brown Motion Model', in which cosmic rays move on the lattice and are scattered at the grid point anisotropically. Another is 'diffusion model' where we solve the diffusion equation with anisotropic magnetic field.
In 'Brown Motion Model', the distance between grid points is estimated from the observation, if we assume cosmic rays of the higher energy have the more tendency to preserve the original direction. This tendency is derived from the turbulent magnetic field, and this approach turns out to be promising.
In 'diffusion model', the analytic solution is obtained for the first time for the boundary condition including both the galactic plane and the halo. The solution is not so simple as to compare with the observations. So exploration of the parameters is not enough, but we can reproduce the 'knee' under the certain set of the parameters.
These results are summarized as the master theses under my supervision. These are 'The stochastic model of cosmic ray propagations' 'The cosmic ray propagation in anisotropic galactic magnetic fields', 'The random walk model of cosmic rays in the galaxy with the halo' and 'The scattering of cosmic rays in the random magnetic field'. Two of four are now studying at the doctor course of National Astronomical Observatory and we will publish the results with them soon.
Following this track, we can get the average structure of the magnetic field in the Galaxy and can get the better understanding of the cosmic propagation.