HIGH-LATITUDE ULYSSES OBSERVATIONS OF CIR ACCELERATED IONS AND ELECTRONS

From the comparison of the intensity maxima of similar to 1 MeV/nuc. i ons with those of the 40-65 keV electrons and higher energy ions (simi lar to 2-4 and 4-8 MeV/nuc.), during Ulysses' ascent to the solar sout h pole, 1992-1994, evidence has been found for the similar to 1 MeV/nu c. ions observed at high latitude by the Ulysses spacecraft to have or iginated at mid-latitudes and greater radial distances. The key observ ations presented in this paper are; i) The similar to 1 MeV/nuc.) ion intensity maxima were observed to decay exponentially with latitude, a bove the streamer belt, whereas the electron intensity maxima and high er energy (similar to 4-8 MeV/nuc.) ion intensity maxima varied about a constant level, ii) When the ratios were taken of the ion intensity maxima to the electron intensity maxima for each of the CIR events, ab ove the streamer belt, the ratios decayed exponentially with latitude, and iii) Upon the spacecraft's departure from the streamer belt, the electron maxima were observed to be delayed by similar to 1-4 days, wi th respect to the similar to 1 MeV/nuc. ion maxima. Within the streame r belt they had been typically simultaneous. Evidence was also found f or a delay in the higher energy (greater than or similar to 2 MeV/nuc. ) ions with respect to the lower energy similar to 1 MeV/nuc. ions. Fr om the exponential decay of the ion/electron ratios above the streamer belt, we concluded that the similar to 1 MeV/nuc. ions originated fro m the CIR reverse shock at lower latitudes and greater radial distance s, along with the electrons. The observed delays in the electrons and higher energy ions were a consequence of the particles travelling from the distant reverse shack. Hence, it appears that the ions were accel erated at the reverse shock at lower latitudes, and not at the local p oleward propagating reverse shocks as had been previously suggested.