The scattering of cosmic rays by the stars of a galaxy

Abstract

The problem dealt with in this note may be formulated in the following way: imagine a galaxy of N stars, each carrying a magnetic dipole of moment μ(n) (n=1, 2, …N) and assume that the density, defined as the number of stars per unit volume, varies according to any given law, while the dipoles are oriented at random because of their very weak coupling. Under this condition the resultant field of the whole galaxy almost vanishes. Let there be an isotropic distribution of charged cosmic particles entering the galaxy from outside. Our problem is to find the intensity distribution in all directions around a point within the galaxy. Its importance arises from the fact that if the distribution should prove to be anisotropic a means would be available for determining whether cosmic rays come from beyond the galaxy, independent of the galactic rotation effect already considered by Compton and Getting. (1)