The dust distribution within the inner coma of comet P/Halley 1982i - Encounter by Giotto's impact detectors

Analysis of the data from Giotto's Dust Impact Detection System experiment (DIDSY) is presented. These data represent measurement of the size of dust grains incident on the Giotto dust shield along its trajectory through the coma of comet P/Halley on 1986 March 13/14. First detection occurred at some 287,000 km distance from the nucleus on the inbound leg; the majority of the DIDSY subsystems remained operational after closest approach (604 km) yielding the last detection at about 202,000 km from the nucleus. In order to improve the data coverage (and especially for the smallest grains, to approximately 10^-19kg particle mass), data from the PIA instrument has been combined with DIDSY data. For the close encounter period (-5 min to +5 min), the cumulative mass distribution function has been investigated.