Effects of a Ring Current on Cosmic Radiation

A theoretical analysis of the effect of an equatorial ring current on the latitude variation of the primary cosmic radiation has been carried out. It has been found that a ring current of the size suggested by Schmidt should lead to observable effects on the latitude variation. In particular, if a ring current of radius equal to 7.5 earth radii and current strength sufficient to produce a field of $100\gamma$ at the earth's equator exists, then the knee in the latitude variation is a feature of the rigidity cut-off curve rather than of the primary spectrum. The primary spectrum obtained with the use of geomagnetic theory which includes a ring current is satisfactorily fitted with a function of the form $J=0.29\mathrm{}{E}^{-0.9\mathrm{}}$ ${\left({\mathrm{cm}}^2\mathrm{s}\mathrm{e}\mathrm{c}\mathrm{s}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{a}\mathrm{d}\right)}^{-1\mathrm{}}$, where $E$ is the total energy of a primary particle. Certain features of time variations of the cosmic-ray intensity apparently disagree with the theory.