Voyager 2 observations related to the October-November 2003 solar events

Abstract

A transient flow system observed at 1 AU from October 24-November 7, 2003 (consisting of several shocks, ejecta and possibly other flows) moved away from the Sun for ≈180 days to 73 AU, where Voyager 2 (V2) observed a large Merged Interaction Region (MIR) associated with a fast (560 km/s) stream that followed a forward shock and moved past V2 for ≈1.5 solar rotations. The MIR and stream were associated with a large decrease in the cosmic ray intensity and an exceptionally large enhancement in the flux of ≈2.5 MeV protons. The speed and the cosmic ray profiles observed by V2 were very simple, resembling the profiles of a shock/sheath/ejecta flow and a Forbush decrease, respectively, at 1 AU, but rescaled by a factor by a factor of ≈10. The onset of the MIR-associated decrease in the cosmic ray intensity occurred 10 days after the shock, lasting several days, with a full recovery ≈70 days after the onset. Copyright 2005 by the American Geophysical Union.