Stochastic acceleration of cometary pickup ions - The classic leaky box model

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/167510· OSTI ID:5642388

Barbosa, D D ^[1]

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1. California Univ., Los Angeles (USA)

The acceleration of cometary pickup ions by magnetohydrodynamic waves at P/Giacobini-Zinner is examined in a model where acceleration predominantly occurs downstream of the bow shock throughout the cometosheath where intense magnetic turbulence exists. The mean free path for scattering by the magnetic fluctuations in this region is less than the characteristic dimension of the cometosheath so that pickup ions are rendered isotropic and energized by a modest amount in the process. This principal loss mechanism for the ions is spatial diffusion out of the acceleration region moderated by the self-same accelerating waves. This particular feature constrains the model in a way that the predicted ion spectrum is uniquely determined by the power spectrum of the magnetic turbulence. At both P/Giacobini-Zinner and P/Halley, the turbulence is non-Kolmogoroff with a spectral index of 2 resulting in an ion spectral behavior that is approximately an exponential in ion speed, consistent with a recent analysis of the Giacobini-Zinner data (see Richardson et al.). 44 refs.

• OSTI ID: 5642388
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 341; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ATMOSPHERES
COMETS
COSMIC RADIATION
FLUID MECHANICS
HALLEY COMET
HYDRODYNAMICS
HYDROMAGNETIC WAVES
INTERPLANETARY SPACE
ION TEMPERATURE
IONIZING RADIATIONS
MAGNETOHYDRODYNAMICS
MATHEMATICAL MODELS
MECHANICS
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
RADIATIONS
SHOCK WAVES
SPACE
TURBULENCE