C.G. Maclennan and L.J. Lanzerotti Bell Laboratories, Lucent Technologies, Murray Hill, NJ USA R.B. Decker, R.E. Gold, S.E. Hawkins, III, and D. Haggerty Johns Hopkins University/Applied Physics Lab, Laurel, MD USA
The beginning and rise to maximum of solar cycle 23 has the Ulysses spacecraft fortuitously placed at ~5 AU near the ecliptic plane and on a trajectory toward the southern heliosphere pole. The twin instruments, HI-SCALE on Ulysses and EPAM on the ACE spacecraft (at 1 AU), provide an opportunity at this time in the solar cycle to investigate the spatial distribution of charged, solar-produced particles in the near-ecliptic heliosphere inside 5 AU. We report here examinations and comparisons of the composition (Z > 2 ions) of heliosphere particles with energies ~0.5-10 MeV/nucl during the years 1998 to the present as measured at these two locations. In particular, we compare the composition radial gradients between 1 and 5 AU as a function of helioradius and heliolatitude, as Ulysses begins its southward swing during its solar maximum mission. We also show comparisons of the ion composition as a function of heliolatitude for Ulysses first two orbits over the same southern heliolatitude range.