Stochastic acceleration of cometary pickup ions - The classic leaky box model
Abstract
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.
- Authors:
-
- California Univ., Los Angeles (USA)
- Publication Date:
- OSTI Identifier:
- 5642388
- Resource Type:
- Journal Article
- Journal Name:
- Astrophysical Journal; (USA)
- Additional Journal Information:
- Journal Volume: 341; Journal ID: ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMETS; MATHEMATICAL MODELS; ACCELERATION; COSMIC RADIATION; HALLEY COMET; HYDROMAGNETIC WAVES; INTERPLANETARY SPACE; ION TEMPERATURE; MAGNETOHYDRODYNAMICS; PLANETARY MAGNETOSPHERES; SHOCK WAVES; TURBULENCE; ATMOSPHERES; FLUID MECHANICS; HYDRODYNAMICS; IONIZING RADIATIONS; MECHANICS; PLANETARY ATMOSPHERES; RADIATIONS; SPACE; 640107* - Astrophysics & Cosmology- Planetary Phenomena
Citation Formats
Barbosa, D D. Stochastic acceleration of cometary pickup ions - The classic leaky box model. United States: N. p., 1989.
Web. doi:10.1086/167510.
Barbosa, D D. Stochastic acceleration of cometary pickup ions - The classic leaky box model. United States. https://doi.org/10.1086/167510
Barbosa, D D. 1989.
"Stochastic acceleration of cometary pickup ions - The classic leaky box model". United States. https://doi.org/10.1086/167510.
@article{osti_5642388,
title = {Stochastic acceleration of cometary pickup ions - The classic leaky box model},
author = {Barbosa, D D},
abstractNote = {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.},
doi = {10.1086/167510},
url = {https://www.osti.gov/biblio/5642388},
journal = {Astrophysical Journal; (USA)},
issn = {0004-637X},
number = ,
volume = 341,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 1989},
month = {Thu Jun 01 00:00:00 EDT 1989}
}