Ulysses in the south polar cap at solar maximum: Heliospheric magnetic field

Observations during the recent ascent of Ulysses to the south polar region are reported. Large variations in field magnitude are associated principall y with solar wind interaction regions. The observed spiral angle agrees rea sonably well with the Parker model. The magnetic flux, the product of the r adial field component and the square of the radial distance (r(2) B-R), is independent of latitude implying non-radial expansion of the solar wind. Tw o magnetic sectors are present up to a latitude of approximate to -78 degre es above which a single negative (inward) polarity is observed consistent w ith the polar field not yet having reversed. Crossings between sectors, ext rapolated back to the sun, appear consistent with a single warped current s heet tilted slightly to the rotation axis. Field lines in the polar region passing near the cur-rent sheet originate at low latitudes. They provide ac cess of high energy solar particles to the polar region.