Giotto Comet Halley Dust Impact experiment: Studies of discrete impact events

Abstract

Analysis of discrete pulse height data from specific individual events of the Giotto Comet Halley Dust Impact Detectors DID-1 and DID-4 has been completed. The cumulative flux for the mid-size range of this Giotto comet dust experiment has been studied and results are presented. The technique employed in the investigation utilized a constant number of events for each data sample, thus providing a variable time interval for each sample group. A cumulative flux was calculated and the data window shifted for additional flux calculations. This provided the basis for a presentation of the cumulative flux detected by the experiment from event one of pre-encounter time through a post-encounter period of 1000s. Inside the cometopause, anomalous peaks, followed by plateaus, are observed which deviate from a 1/R² curve, seen in both pre- and post-encounter data. The relationship of these flux variations to plasma depletion zones, magnetic pile-up regions and the contact surface zone is discussed.