The Solar Wind Velocity at High Solar Activity: A Search for Latitudinal Effects

Observations by Ulysses during its second out-of-ecliptic orbit have shown that at high solar activity the solar wind appears as a highly variable flow at all heliolatitudes. In the present study Ulysses data from southern latitudes greater than 50 degrees are compared to the contemporary ACE data on the ecliptic plane to search for the presence of latitudinal effects in the large-scale structure of the solar wind velocity. The comparison is performed through a multi-scale statistical analysis of the velocity fluctuations at scales from 1 to 64 days. The results indicate that, from a statistical point of view, no difference appears to exist between the wind velocity pattern at the highest latitudes of the Ulysses southern polar phase and that observed by ACE on the ecliptic.