|Dr. Anatoly Lagutin (Altai state university, Russia)|
|"Anomalous diffusion of cosmic rays in the Galaxy"|
A key to understanding the mechanism of cosmic-ray origin and acceleration is the determination of how cosmic-ray particles propogate through the interstellar medium (ISM). If the medium is a quasi- homogeneous the propagation process can be described by Ginzburg- Syrovatskyfs normal diffusion model.
However, recent results show that homogeneous diffusion models failed to reproduce observations. Multiscale structures in the Galaxy, found during the last few decades, may be taken as a support to this conclusion.
Theory and observations show that the ISM is inhomogeneous (fractal- like) on the hundreds of parsecs scales. The stars formation regions also demonstrate fractal features with a spatial scales up to about a kpc.
The particles emitted by Galactic sources en route to the Solar system pass through the regions of the Galaxy that have different properties. In such inhomogeneous ISM, the normal diffusion model certainly is not kept valid.