The effect of p-modes on thin magnetic flux tubes

Abstract

We examine the effect of p-modes impinging on thin magnetic flux tubes. The aim of the study is to see whether global p-modes can excite wave motions of significant amplitude in a magnetic flux tube. For simplicity we treat an isothermal flux tube with the same temperature as the external gas. We calculate the linear response of the tube when p-modes in the ambient are incident on it. This interaction leads to the excitation of a tube wave, which is allowed to leak out of the lower boundary. In general we find that the interaction is non-resonant, in contrast to the unstratified tube. The amplitude of the tube wave is largest for external p-modes of low degree and moderate order. We also calculate the absorption cross-section of p-modes by flux tubes.