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Title: Alfvén wave propagation through a moderate-amplitude transverse inhomogeneity in a magnetized plasma

Abstract

Parallel propagation of a plane Alfvén wave in a moderate-amplitude Gaussian-shaped transverse inhomogeneity is studied numerically using a fluid model retaining low-frequency kinetic effects. It is shown that in such a situation, common in the solar wind where elongated pressure-balanced structures are frequently observed, phase mixing competes with wave focusing, in contrast with coronal loops or auroral regions where sharp gradients present at the edges of the inhomogeneities make phase mixing dominant. Some understanding about this competition is provided by a model based on an envelope formalism. Depending on the magnitude of the Alfvén wavelength and of the inhomogeneity transverse scale relative to the ion inertial length, various regimes can develop, ranging from the formation of localized gradients when phase mixing dominates to the development of an intense magnetic filament when focusing is stronger, with a different efficiency for the generation of magnetosonic and kinetic Alfvén waves. Electron parallel heating and parallel electric field generation are also briefly discussed.

Authors:
; ; ;  [1]
  1. Laboratoire Lagrange, Université Côte d'Azur, CNRS, Observatoire de la Côte d'Azur, CS 34229, 06304 Nice Cedex 4 (France)
Publication Date:
OSTI Identifier:
22599896
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AMPLITUDES; BALANCES; ELECTRIC FIELDS; ELECTRONS; FILAMENTS; FLUIDS; FOCUSING; GAUSSIAN PROCESSES; HEATING; LENGTH; MIXING; PLASMA; SOLAR WIND; WAVE PROPAGATION; WAVELENGTHS

Citation Formats

Borgogno, D., Laveder, D., Passot, T., and Sulem, P. L. Alfvén wave propagation through a moderate-amplitude transverse inhomogeneity in a magnetized plasma. United States: N. p., 2016. Web. doi:10.1063/1.4960998.
Borgogno, D., Laveder, D., Passot, T., & Sulem, P. L. Alfvén wave propagation through a moderate-amplitude transverse inhomogeneity in a magnetized plasma. United States. doi:10.1063/1.4960998.
Borgogno, D., Laveder, D., Passot, T., and Sulem, P. L. 2016. "Alfvén wave propagation through a moderate-amplitude transverse inhomogeneity in a magnetized plasma". United States. doi:10.1063/1.4960998.
@article{osti_22599896,
title = {Alfvén wave propagation through a moderate-amplitude transverse inhomogeneity in a magnetized plasma},
author = {Borgogno, D. and Laveder, D. and Passot, T. and Sulem, P. L.},
abstractNote = {Parallel propagation of a plane Alfvén wave in a moderate-amplitude Gaussian-shaped transverse inhomogeneity is studied numerically using a fluid model retaining low-frequency kinetic effects. It is shown that in such a situation, common in the solar wind where elongated pressure-balanced structures are frequently observed, phase mixing competes with wave focusing, in contrast with coronal loops or auroral regions where sharp gradients present at the edges of the inhomogeneities make phase mixing dominant. Some understanding about this competition is provided by a model based on an envelope formalism. Depending on the magnitude of the Alfvén wavelength and of the inhomogeneity transverse scale relative to the ion inertial length, various regimes can develop, ranging from the formation of localized gradients when phase mixing dominates to the development of an intense magnetic filament when focusing is stronger, with a different efficiency for the generation of magnetosonic and kinetic Alfvén waves. Electron parallel heating and parallel electric field generation are also briefly discussed.},
doi = {10.1063/1.4960998},
journal = {Physics of Plasmas},
number = 8,
volume = 23,
place = {United States},
year = 2016,
month = 8
}
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