A magnetohydrodynamical model of the inner coma of comet Halley

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA11p15025· OSTI ID:5947594

Cravens, T E ^[1]

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1. Univ. of Michigan, Ann Arbor (USA)

The magnetometer onboard the Giotto spacecraft observed a diamagnetic cavity surrounding the nucleus of comet Halley. The location of the boundary of this boundary of this diamagnetic cavity is determined by a balance between an inward magnetic pressure gradient force and an outward ion-neutral drag force, associated with collisions between the outwardly flowing neutrals and the stagnated ions. A one-dimensional, time-dependent, magnetohydrodynamical model has been developed for the inner coma of comet Halley, and includes ion-neutral collisions, photochemical production and loss of plasma, and finite conductivity. This model is used to investigate the plasma dynamics in the vicinity of the diamagnetic cavity boundary surface. A narrow transition layer with enhanced plasma density is shown to exist just inside the boundary, although a full understanding of this layer will require a two- or three-dimensional MHD model. The flux of cometary ions into this shocklike layer is removed by electron-ion recombination. The thickness of this layer is determined by the Mach number of the incident flow.

• OSTI ID: 5947594
• Journal Information: Journal of Geophysical Research; (USA), Vol. 94:A11; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HALLEY COMET
MATHEMATICAL MODELS
DRAG
DYNAMICS
ION-ATOM COLLISIONS
IONS
MAGNETOHYDRODYNAMICS
MORPHOLOGY
ONE-DIMENSIONAL CALCULATIONS
PHOTOCHEMISTRY
PLASMA
PLASMA DENSITY
PRESSURE GRADIENTS
RECOMBINATION
SPACE VEHICLES
TIME DEPENDENCE
ATOM COLLISIONS
CHARGED PARTICLES
CHEMISTRY
COLLISIONS
COMETS
FLUID MECHANICS
HYDRODYNAMICS
ION COLLISIONS
MECHANICS
VEHICLES
640107* - Astrophysics & Cosmology- Planetary Phenomena