LOW-ENERGY CHARGED-PARTICLES IN THE HIGH-LATITUDE HELIOSPHERE

Low energy ion and electron measurements made over the south and north polar regions of the sun by the HI-SCALE instrument on the Ulysses sp acecraft during its solar minimum polar passages are summarized. The p olar flux levels were considerably reduced in comparison to fluxes in the vicinity of the heliospheric current sheet. Flux variations with a period of similar to 26 days were seen to nearly 80 degrees S but wer e not observed over the northern pole. Solar particle events originati ng from near-equatorial activity were seen at high southern latitudes, but not at high northern latitudes. Comparisons with in-ecliptic meas urements made during the same time interval on the IMP8 spacecraft sug gest that the polar differences are largely spatial and not temporal. The flux of low energy (similar to 0.8-5.0 MeV/nucl) anomalous oxygen was measured to be similar to 50% higher over the northern polar regio n than in the south. The flux of solar wind iron, measurable because o f its convection into the instrument by the high speed polar solar win d, is estimated to be about a factor of two larger over the south pole than over the north.