On the periodic variations of secondary cosmic rays and the geomagnetic Pc4 pulsations in BMAr

In a set of balloon flights in the Brazilian magnetic anomaly region (BMAr) short time periodic variations were observed, i.e. pulsation, of secondary charged and neutral particle fluxes, X- and -ray fluxes with amplitudes of about 2–4%. The pulsations are accompanied by the geomagnetic Pc4 pulsations and have similar periodicity. The phenomenon was observed over various local times and in quiet and disturbed magnetospheric conditions. One of the explanations of this effect, i.e. periodic variation of local cut-off rigidity, and following pulsations of primary and secondary cosmic ray intensity is suggested.     

Non-diffusive particle pulse transport – Application to an anisotropic solar GLE

A theory of the transport of an anisotropic pulse of charged particles injected into the interplanetary magnetic field is applied to an anisotropic ground level event on 24 May 1990. For this event the kinetic regime is considered when the mean free path is comparable with the distance from particle source. Both the source angular particle distribution and the angular dependence of a detector response are included. The theoretically predicted temporal profiles are compared with the particle intensity records measured by several neutron monitors with different asymptotic directions.