THE BAND OF SOLAR-WIND VARIABILITY AT LOW HELIOGRAPHIC LATITUDES NEAR SOLAR-ACTIVITY MINIMUM - PLASMA RESULTS FROM THE ULYSSES RAPID LATITUDE SCAN

Near solar activity minimum large variations in the quiescent solar wind now are confined to a narrow latitude band centered near the heliographic equator. During Ulysses' recent rapid latitude scan this band was similar to 43 degrees wide. Flow parameters poleward of the band in the opposite solar hemispheres were nearly the same. Main entry into the band of variable solar wind was via a shock disturbance most likely associated with over-expansion of a coronal mass ejection event. Wind variability within the band was associated primarily with longitudinal structure in the solar corona and solar rotation; high-speed streams observed there were associated with locations where the polar coronal holes extended equatorward toward the Ulysses orbit. Observations indicate that the polar coronal holes at this time occupied only similar to 13% of the low Corona, yet a nearly uniform high-speed wind (average speed similar to 750 km s(-1)) filled similar to 63% of the heliosphere. This indicates the holes expanded by a factor of similar to 4.8 from the low corona to interplanetary space. Much of this lateral expansion occurred beyond 1.74 solar radii from Sun center.