ULYSSES OBSERVATIONS OF A RECURRENT HIGH-SPEED SOLAR-WIND STREAM AND THE HELIOMAGNETIC STREAMER BELT

Near-ecliptic solar wind observations by Ulysses on its way to the pol ar regions of the Sun, compared with those from IMP 8 at 1 AU, showed that high-speed streams decay and broaden with heliocentric distance f rom IMP 8 to Ulysses, as expected. In July 1992 while travelling south at approximately 13-degrees-S and 5.3 AU, Ulysses encountered a recur rent high-speed stream, that may also have been observed at IMP 8. The stream has been observed a total of 14 times, once in each solar rota tion through June 1993 at approximately 34-degrees-S. The source of th e high-speed stream is an equatorward extension of the south polar cor onal hole. From July 1992 through June 1993, averages of solar wind pe ak speed increased while density decreased with heliographic latitude. Both the stream and a low-speed, high-density flow, presumably associ ated with the heliomagnetic (coronal) streamer belt encircling the hel iomagnetic equator, crossed Ulysses with the solar rotation period unt il April 1993 when the spacecraft was at approximately 29-degrees-S he liographic latitude. After this time, as the spacecraft climbed to hig her latitudes, the central portion of the streamer belt with lowest sp eed and highest density disappeared. Therefore, at its maximum inclina tion, the belt was tilted at approximately 29-degrees to the heliograp hic equator at this point in the solar cycle.