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Giotto magnetic field observations at the outbound quasi-parallel bow shock of comet Halley.

Coates, A. J.; Neubauer, F. M.; Glassmeier, K. H. +4 more

The investigation of the outbound bow shock of comet Halley using Giotto magnetometer data leads to the following results: the shock is characterized by strong magnetic turbulence associated with an increasing background magnetic field and a change in direction by 60° as one goes inward. The thickness of the quasi-parallel shock was 120000 km. The…

Interpretation of the inner coma observations of comet P/Halley by the Halley Multicolour Camera.

Keller, H. U.; Thomas, N.

The brightness dependence with distance of the inner coma of comet P/Halley, as observed by the Halley Multicolour Camera on board Giotto, shows 3 distinct regions. From about 400 - 2000 km from the nucleus, deviations from a z^-1 law are evident where z is the distance from the nucleus centre. Fountain model calculations indicate that s…

Giotto IMS measurements of the production rate of hydrogen cyanide in the coma of comet Halley.

Schwenn, R.; Balsiger, H.; Geiss, J. +7 more

The ion composition measurements in the ionosphere of comet Halley by the ion mass spectrometer (IMS) experiment on the Giotto spacecraft are used to estimate the relative abundance of HCN. From a comparison of the normalized number density of ions with mass-to-charge (M/q) ratio of 28 AMU/e with steady-state photochemical models, it can be determ…

Cometary ion flow variations at comet P/Halley as observed by the Giotto IMS experiments.

Schwenn, R.; Balsiger, H.; Ip, W. -H. +5 more

Using the combined data sets from the angle analyzer and the mass analyzer of the Giotto IMS-HIS experiment, the authors have derived the three-dimensional plasma flow properties of cometary ions for masses ≥12 AMU. The results are in agreement with the theoretical model of charge exchange loss of the hot cometary ions.

Particle observations by EPA/EPONA during the outbound pass of Giotto from comet Halley and their relationship to large scale magnetic field irregularities.

Neubauer, F. M.; Ip, W. -H.; Daly, P. +5 more

The acceleration processes producing spikes seen superimposed on the general intensity time profile of energetic particles obtained with EPA/EPONA during the outbound pass of Giotto on 14/15 March 1986, are studied using complementary magnetic field data. Three different types of spikes were identified. Evidence for the ion pick-up process and pro…