EDP Sciences
Free access
Issue
A&A
Volume 369, Number 3, April III 2001
Page(s) 1122 - 1139
Section Physical and chemical processes
DOI http://dx.doi.org/10.1051/0004-6361:20010171


A&A 369, 1122-1139 (2001)
DOI: 10.1051/0004-6361:20010171

Numerical simulations of linear magnetohydrodynamic waves in two-dimensional force-free magnetic fields

I. Arregui, R. Oliver and J. L. Ballester

Departament de Física, Universitat de les Illes Balears, 07071 Palma de Mallorca, Spain
    e-mail: ramon.oliver@uib.es; dfsjlb0@ps.uib.es

(Received 4 August 2000 / Accepted 26 January 2001)

Abstract
High resolution observations of the solar corona made with instruments onboard the SOHO and TRACE spacecrafts have provided new evidence for the presence of oscillations in a variety of coronal magnetic structures. Most of these observations have been interpreted in terms of linear standing or propagating magnetohydrodynamic (MHD) waves, but the theoretical understanding is far from complete since analytical solutions to the linearised MHD wave equations can only be found for very simple magnetic configurations. Taking into account that the solar corona is basically structured by force-free magnetic fields, our purpose in this paper is to present the derivation of the linear MHD wave equations for a two-dimensional force-free magnetic field configuration having longitudinal invariance, as well as to introduce a numerical code to solve the resulting system of coupled partial differential equations. The accuracy of the code has been checked by numerically solving two cases for which analytical or simple numerical solutions exist. To our knowledge, this is the only two-dimensional code developed to study the normal MHD modes of oscillation of a general force-free field with longitudinal invariance.


Key words: magnetohydrodynamics -- methods: numerical -- Sun: oscillations -- Sun: magnetic fields

Offprint request: I. Arregui, arregi@hubble.uib.es




© ESO 2001