Ulysses scientists try to catch the solar wind
20 April 1999
More than 50 scientists met at the European Space Research and TechnologyCentre (ESTEC) in Noordwijk, Netherlands, on 14, 15 and 16 April to discuss the latest scientific results to come from the Ulysses out-of-eclipticmission.Meeting for the 41st time in its long history (the first meeting took place over 20 years ago at JPL in May, 1978), the Ulysses Science Working Team (SWT) reviewed the status of the mission, and actively debated the recent scientific findings reported in more than 30 presentations.
Of particular interest was the question "Has Ulysses once again caught up with the fast solar wind?" Presently located some 25 degrees below the Sun's equator, Ulysses has reached the latitude at which, earlier in the mission, it became immersed in fast flowing solar wind from the polar regions. All indications are, however, that this time the boundary between the fast polar wind and slow wind from the equatorial belt is out-running the spacecraft as it heads poleward. Scientists expect that the well ordered pattern of fast and slow wind that Ulysses encountered near solar minimum will give way to a more chaotic situation as solar activity increases. The continued absence of prolonged periods of fast wind at Ulysses seems to bear this out.
Another Ulysses experiment has detected samples of solar wind material that have been absorbed by dust particles in the inner heliosphere, only to be re-emmited at a later time to become a separate population of energetic particles.
