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Relationship between wave energy and free energy from pickup ions in the Comet Halley Environment

Johnstone, A. D.; Huddleston, D. E.

The free energy available from the implanted heavy ion population at comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. We obtain upstream and downstream free energies separately for t…

Quasi-linear velocity space diffusion of heavy cometary pickup ions on bispherical diffusion characteristics

Coates, A. J.; Johnstone, A. D.; Huddleston, D. E.

We consider an ion transport equation describing the source, convection, adiabatic acceleration, and quasi-linear velocity diffusion of cometary pickup ions. The equation is solved numerically along solar wind plasma flow lines for the environment of comet Halley, to obtain distributions at positions on the Giotto spacecraft trajectory which may b…

Observations of Plasma Dynamics in the Coma of P/Halley by the Giotto Ion Mass Spectrometer

Schwenn, R.; Balsiger, H.; Ip, W. -H. +7 more

Observations in the coma of P/Halley by the Giotto ion mass spectrometer (IMS) are reported. The high-energy range spectrometer (HERS) of the IMS obtained measurements of protons and alpha particles from the far upstream region to the near ionopause region and of ions of mass 12-32 at distances of about 250,000 to 40,000 km from the nucleus. Plasm…

Properties of mass-loading shocks 2. Magnetohydrodynamics

Neubauer, F. M.; Zank, G. P.; Oughton, S. +1 more

The one-dimensional magnetohydrodynamics of shocked flows subjected to significant mass loading are considered. Recent observations at comets Giacobini-Zinner and Halley suggest that simple nonreacting MHD is an inappropriate description for active cometary bow shocks. The thickness of the observed cometary shock implies that mass loading represen…

Electron distributions upstream of the comet Halley bow shock: Evidence for adiabatic heating

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

We report on three-dimensional plasma electron (22 eV to 30 keV) observations upstream of the comet Halley bow shock, obtained by the RPA-1 COPERNIC (Rème Plasma Analyzer-Complete Positive Ion, Electron and Ram Negative Ion Measurements near Comet Halley) experiment on the Giotto spacecraft. Besides electron distributions typical of the undisturbe…