A Review of Discontinuities (and Alfv6n Waves) in Interplanetary Space: Uiysses Results

The Ulysses mission explored for the first time our heliosphere at all latitudes up to * 80 and therefore has been an ideal mission to study potential gradients in heliolatitude (and radial distance) of discontinuity occurrence rates and types, Directional discontinuities (DDs) are shown to be dependent on the type of solar wind streams that they are embedded in. There are 5 to 10 times as many DDs in high-speed streams as in slow speed streams. The explanation is that rotational discontinuities (RDs) are the phase-steepened edges of Alfv6n waves. The nonlinear Alfw % waves in high-speed streams have ~/BO-1-2, and are arc-polarized spherical waves. Dissipation at these “intermediate shocks ” (the RDs) have been sought, but not found. A