8. Summary and conclusions
We have used a potential magnetic field with equilibrium plasma quantities exponentially decaying with height as a simplified model of a coronal arcade. Fast magnetosonic waves have been launched at a fixed spatial location of the arcade. The slow and Alfvén modes have been eliminated by considering the low plasma limit and by taking , , respectively.
The strategy we followed was to reduce the general MHD problem of wave excitation in a coronal arcade, to a simple yet relevant model problem. The physical conditions established in the model presented in this paper are relatively simple-no gravity and no pressure terms being implemented. These and other simplifying assumptions disqualify the results for being suitable for a direct comparison with observations, although the present problem still contains enough physics to study time-dependent wave propagation. Our model is an extension of the latest numerical simulations by Murawski & Roberts (1994) and Murawski & Goossens (1994), which were performed for straight magnetic field topology. However, we have benefited from these studies as we have gained an improved physical insight into the process of wave propagation in a curved magnetic field. This insight will be used in subsequent, more realistic investigations in which those assumptions will be relaxed.
© European Southern Observatory (ESO) 1998
Online publication: January 16, 1998