Coronal Mass Ejections in the solar wind at high solar latitudes: an overview

Ulysses has provided the first direct measurements of coronal mass ejections, CMES, in the solar wind at high heliographic latitudes. This paper provides an overview of new and unexpected results from the plasma experiment on Ulysses, supplemented with magnetic field measurements, during the spacecraft`s first excursion to high solar latitudes. A striking aspect of the high-latitude CMEs observed is that they all had high speeds, with the overall average speed being 730 km s{sup {minus}1}. A new class of forward-reverse shock pairs, associated with expansion of CMES, has been discovered at high latitudes. Of six certain CMEs observed at high latitudes, three have associated shock pairs of this nature. Combined Ulysses and Yohkoh observations suggest that the flux rope topology characteristic of some CMEs results from reconnection within the legs of neighboring magnetic loops embedded within the escaping CMES.