Sources of the Solar Wind at Ulysses during 1990-2006

Abstract

The Ulysses spacecraft is now well into its third polar orbit around the Sun. Using stackplot displays, we summarize the wind speeds and interplanetary sector polarities recorded by Ulysses since its launch in 1990 and relate the observed patterns to the global evolution of open magnetic regions (coronal holes) over the solar cycle. We verify that the wind speeds are inversely correlated with the rate of flux-tube divergence in the corona, as derived from a current-free extrapolation of the measured photospheric field. We identify the source of each of the long-lived, high-speed streams encountered by Ulysses and discuss their formation, evolution, and rotational properties.