The heliospheric magnetic field at solar minimum as observed by ULYSSES

Abstract

Since February 1992 the Ulysses spacecraft has been in a polar orbit round the Sun, reaching 80 deg heliolatitude over the south pole in September 1994 and over the north pole in July 1995. During this time solar activity has been gradually declining towards its present minimum in mid-1996. We discuss how the large scale configuration of the heliospheric magnetic field and its embedded current sheet have evolved throughout this period, based upon measurements obtained by the magnetometer experiment on Ulysses, contrasting the snapshot of the field configuration obtained under solar minimum conditions during the fast transit from south pole to north pole with the results from earlier years where the slower traversal of latitude allowed efffects of the evolution of the corona with solar activity to be more apparent.