Phase mixing of nonlinear visco-resistive Alfvén waves

Aims. We investigate the behaviour of nonlinear, nonideal Alfvén wave propagation within an inhomogeneous magnetic environment. Methods. The governing MHD equations are solved in 1D and 2D using both analytical techniques and numerical simulations. Results. We find clear evidence for the ponderomoti...

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Bibliographic Details
Published in:	Astronomy and astrophysics (Berlin) 2011-03, Vol.527, p.A149
Main Authors:	McLaughlin, J. A., De Moortel, I., Hood, A. W.
Format:	Article
Language:	eng
Subjects:	Astronomy Earth, ocean, space Exact sciences and technology magnetic fields magnetohydrodynamics (MHD) shock waves Sun: corona Sun: oscillations waves
Online Access:	Get full text
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Summary:	Aims. We investigate the behaviour of nonlinear, nonideal Alfvén wave propagation within an inhomogeneous magnetic environment. Methods. The governing MHD equations are solved in 1D and 2D using both analytical techniques and numerical simulations. Results. We find clear evidence for the ponderomotive effect and visco-resistive heating. The ponderomotive effect generates a longitudinal component to the transverse Alfvén wave, with a frequency twice that of the driving frequency. Analytical work shows the addition of resistive heating. This leads to a substantial increase in the local temperature and thus gas pressure of the plasma, resulting in material being pushed along the magnetic field. In 2D, our system exhibits phase mixing and we observe an evolution in the location of the maximum heating, i.e. we find a drifting of the heating layer. Conclusions. Considering Alfvén wave propagation in 2D with an inhomogeneous density gradient, we find that the equilibrium density profile is significantly modified by both the flow of density due to visco-resistive heating and the nonlinear response to the localised heating through phase mixing.
ISSN:	0004-6361 1432-0746