The Solar Wind in Three Dimensions

Abstract

Ulysses, which is in a polar orbit about the Sun, is providing the first direct observations of the solar wind at high heliographic latitudes. Among the new results from Ulysses summarized here are the following: 1. On the declining phase of the solar activity cycle and near solar minimum solar wind variability is largely confined to a relatively narrow latitude band centered on the heliographic equator. 2. Solar wind speed far from the Sun is anti-correlated with ionization temperature in the low corona. 3. A polytrope of the form T = (2.0 × 105)N 0.57, where T and N are the proton density and temperature, describes the free expansion of the high-speed wind at high latitudes. 4. Equipartition of plasma and magnetic field energy does not occur in the high-speed wind, the plasma beta there typically being ~3.0. 5. Corotating interaction regions have opposed north-south tilts in the northern and southern hemispheres. 6. A new class of forward-reverse shock pairs associated with over-expanding coronal mass ejections has been identified at high heliographic latitudes.KeywordsSolar WindCoronal Mass EjectionSolar Wind SpeedHeliocentric DistanceHeliospheric Current SheetThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.