Outer radiation belt of relativistic electrons during the minimum of the 23rd solar cycle

Abstract

The data on fluxes of electrons with energy Ee > 1 MeV and on radiation doses under the Al shielding of about 2 g/cm2 measured on the GLONASS satellite (circular orbit with altitude 20000 km and inclination 65°) for the period from December 2006 through May 2010 are analyzed. The minimum of the 23rd solar cycle turned out to be the longest for all over the space exploration age. Consequently, average semiannual electron fluxes and daily radiation doses are showing the decrease by more than an order of magnitude in comparison with the levels observed in 2007. We present an example of a diffusion wave of relativistic electrons; the wave develops in a period between magnetic storms. This process may result in a significant increase of the radiation dose measured in the orbit, even under the conditions of weak geomagnetic disturbances. The dynamics of variations in relativistic electron fluxes during the magnetic storm of April 5–6, 2010, is discussed so far as this is the first strong flux enhancement in the 24th solar cycle.