Pickup water group ions at comet Grigg-Skjellerup
Coates, A. J.; Winningham, J. D.; Borg, H.; Neubauer, F. M.; Amata, E.; Gurgiolo, C.; Formisano, V.; Wilken, B.; Bavassano-Cattaneo, M. B.; Jockers, K.; Johnstone, A. D.; Huddleston, D. E.
United Kingdom, Germany, Sweden, Italy, United States
Abstract
The density and velocity distribution of cometary water group ions was measured by the Giotto spacecraft in the regions upstream and downstream of the ‘bow shock’ at comet Grigg-Skjellerup. The results show that the distributions of ions are ring-like until quite close to the shock, the timescales for pitch angle and energy diffusion appear similar and the ion density follows a r-2 dependence.