On the Sidereal Time Variation of the Cosmic Radiation

If it is supposed that the positive and negative cosmic-ray particles are not equal in number, the resulting space charge will be neutralized by slowly moving ions which should follow the motion of the stars. If the cosmic-ray particles are not isotropic relative to the stellar system, as for example if they do not share the motion of galactic rotation, the relative motion of the slow ions and the cosmic-ray particles of opposite sign produces in effect an electric current. Calculation shows that the resulting magnetic field may become as great as ${10}^{-1\mathrm{}}$ gauss if there is a considerable difference between the number of positive and negative particles. It is shown that the anisotropy corresponding to even a small sidereal time variation of the cosmic radiation would imply such great magnetic fields as to bend the paths of cosmic-ray particles in curves of radii small compared with interstellar distances. Therefore, the high degree of isotropy of the cosmic radiation is a necessary consequence of the fact that it consists mainly of charged particles and does not tell us anything about the place of origin of the radiation.