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Title: Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains

Abstract

Quasi-periodic rapidly propagating wave trains are frequently observed in extreme ultraviolet observations of the solar corona, or are inferred by the quasi-periodic modulation of radio emission. The dispersive nature of fast magnetohydrodynamic waves in coronal structures provides a robust mechanism to explain the detected quasi-periodic patterns. We perform 2D numerical simulations of impulsively generated wave trains in coronal plasma slabs and investigate how the behavior of the trapped and leaky components depend on the properties of the initial perturbation. For large amplitude compressive perturbations, the geometrical dispersion associated with the waveguide suppresses the nonlinear steepening for the trapped wave train. The wave train formed by the leaky components does not experience dispersion once it leaves the waveguide and so can steepen and form shocks. The mechanism we consider can lead to the formation of multiple shock fronts by a single, large amplitude, impulsive event and so can account for quasi-periodic features observed in radio spectra.

Authors:
; ;  [1]
  1. Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)
Publication Date:
OSTI Identifier:
22654378
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 847; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPUTERIZED SIMULATION; DISPERSIONS; DISTURBANCES; EMISSION; EVOLUTION; EXTREME ULTRAVIOLET RADIATION; FAST MAGNETOACOUSTIC WAVES; MAGNETOACOUSTICS; MAGNETOHYDRODYNAMICS; NONLINEAR PROBLEMS; PERIODICITY; PERTURBATION THEORY; PLASMA; SHOCK WAVES; SOLAR CORONA; SPECTRA; SUN; TWO-DIMENSIONAL CALCULATIONS; WAVEGUIDES

Citation Formats

Pascoe, D. J., Goddard, C. R., and Nakariakov, V. M., E-mail: D.J.Pascoe@warwick.ac.uk. Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA8DB8.
Pascoe, D. J., Goddard, C. R., & Nakariakov, V. M., E-mail: D.J.Pascoe@warwick.ac.uk. Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains. United States. doi:10.3847/2041-8213/AA8DB8.
Pascoe, D. J., Goddard, C. R., and Nakariakov, V. M., E-mail: D.J.Pascoe@warwick.ac.uk. Sun . "Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains". United States. doi:10.3847/2041-8213/AA8DB8.
@article{osti_22654378,
title = {Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains},
author = {Pascoe, D. J. and Goddard, C. R. and Nakariakov, V. M., E-mail: D.J.Pascoe@warwick.ac.uk},
abstractNote = {Quasi-periodic rapidly propagating wave trains are frequently observed in extreme ultraviolet observations of the solar corona, or are inferred by the quasi-periodic modulation of radio emission. The dispersive nature of fast magnetohydrodynamic waves in coronal structures provides a robust mechanism to explain the detected quasi-periodic patterns. We perform 2D numerical simulations of impulsively generated wave trains in coronal plasma slabs and investigate how the behavior of the trapped and leaky components depend on the properties of the initial perturbation. For large amplitude compressive perturbations, the geometrical dispersion associated with the waveguide suppresses the nonlinear steepening for the trapped wave train. The wave train formed by the leaky components does not experience dispersion once it leaves the waveguide and so can steepen and form shocks. The mechanism we consider can lead to the formation of multiple shock fronts by a single, large amplitude, impulsive event and so can account for quasi-periodic features observed in radio spectra.},
doi = {10.3847/2041-8213/AA8DB8},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 847,
place = {United States},
year = {Sun Oct 01 00:00:00 EDT 2017},
month = {Sun Oct 01 00:00:00 EDT 2017}
}