Plasma transport induced by kinetic Alfven wave turbulence
- Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033 (Japan)
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)
- X-Computational Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
At the Earth's magnetopause that separates the hot-tenuous magnetospheric plasma from the cold dense solar wind plasma, often seen is a boundary layer where plasmas of both origins coexist. Plasma diffusions of various forms have been considered as the cause of this plasma mixing. Here, we investigate the plasma transport induced by wave-particle interaction in kinetic Alfven wave (KAW) turbulence, which is one of the candidate processes. We clarify that the physical origin of the KAW-induced cross-field diffusion is the drift motions of those particles that are in Cerenkov resonance with the wave: E Multiplication-Sign B-like drift that emerges in the presence of non-zero parallel electric field component and grad-B drift due to compressional magnetic fluctuations. We find that KAW turbulence, which has a spectral breakpoint at which an MHD inertial range transits to a dissipation range, causes selective transport for particles whose parallel velocities are specified by the local Alfven velocity and the parallel phase velocity at the spectral breakpoint. This finding leads us to propose a new data analysis method for identifying whether or not a mixed plasma in the boundary layer is a consequence of KAW-induced transport across the magnetopause. The method refers to the velocity space distribution function data obtained by a spacecraft that performs in situ observations and, in principle, is applicable to currently available dataset such as that provided by the NASA's THEMIS mission.
- OSTI ID:
- 22068809
- Journal Information:
- Physics of Plasmas, Vol. 19, Issue 10; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
58 GEOSCIENCES
ALFVEN WAVES
ASTROPHYSICS
BOUNDARY LAYERS
CHERENKOV RADIATION
DATA ANALYSIS
DIFFUSION
DISTRIBUTION FUNCTIONS
ELECTRIC FIELDS
FLUCTUATIONS
MAGNETOHYDRODYNAMICS
MAGNETOPAUSE
NASA
PARTICLE INTERACTIONS
PHASE VELOCITY
PLASMA
PLASMA DRIFT
RESONANCE
SPATIAL DISTRIBUTION
TURBULENCE