VARIATIONS IN THE GEOMAGNETIC CUTOFF RIGIDITY DURING THE 2015 MARCH MAGNETIC STORM
From measurements of cosmic rays at the world network of stations, we calculated the variations in the planetary system of geomagnetic cutoff rigidity during the 2015 March moderate geomagnetic storm. Within the axisymmetric model for the restricted Earth magnetosphere taking into account the currents at the magne-topause and the ring current, the distance to the subsolar point and the ring current radius were determined, as well as the contribution of the ring current to the variations in the geomagnetic cutoff rigidity and to the Dst-index.