2D hybrid simulations of super-diffusion at the magnetopause driven by Kelvin-Helmholtz instability [electronic resource].
- Published
- Washington, D.C. : United States. Dept. of Energy, 2009.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Additional Creators
- Los Alamos National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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- Restrictions on Access
- Free-to-read Unrestricted online access
- Summary
- This manuscript describes the self-consistent simulation of diffusion at the magnetopause driven by Kelvin-Helmholtz (KH) instability. Two-dimensional hybrid (kinetic ions, fluid electrons) simulations of the most KH-unstable configuration where the shear flow is oriented perpendicular to the uniform magnetic field are carried out. The motion of the simulation particles are tracked during the run and their mean-square displacement normal to the magnetopause is calculated from which diffusion coefficients are determined. The diffusion coefficients are found to be time dependent, with Dₓ ∝ t{sup α}, where α > 1. Additionally, the probability distribution functions (PDF) of the 'jump lengths' the particles make over time are found to be non-gaussian. Such time-dependent diffusion coefficients and non-gaussian PDF's have been associated with so-called 'super-diffusion', in which diffusive mixing of particles is enhanced over classical diffusion. The results indicate that while turbulence associated with the break-down of vortices contributes to this enhanced diffusion, it is the growth of large-scale, coherent vortices is the more important process in facilitating it.
- Report Numbers
- E 1.99:la-ur-09-01442
E 1.99: la-ur-09-1442
la-ur-09-1442
la-ur-09-01442 - Other Subject(s)
- Note
- Published through SciTech Connect.
01/01/2009.
"la-ur-09-01442"
" la-ur-09-1442"
Journal at Geophysical Research ISSN 0148-0227 FT
Gary, S Peter; Winske, Dan; Cowee, Misa M. - Funding Information
- AC52-06NA25396
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