Sensitivity of p-mode absorption on magnetic region properties and kernel functions

¹ Applied Mathematics Department, The University of Sheffield, S3 7RH, UK
e-mail: app07adg@sheffield.ac.uk; R.Jain@sheffield.ac.uk
² JILA, University of Colorado at Boulder, USA
e-mail: hindman@lcd.colorado.edu

Received: 8 October 2010
Accepted: 1 December 2010

Abstract

Aims. Magnetohydrodynamic (MHD) sausage tube waves are excited in magnetic flux tubes by p-mode forcing. These tube waves carry energy away from the p-mode cavity which results in a source of absorption. We wish to see the effect of an ensemble of randomly distributed thin magnetic flux tubes on the absorption of p-modes for the model plage region and also study the effect of the spacial weighting function on the theoretically calculated absorption coefficients.

Methods. We calculate the absorption coefficients of p modes for a model plage, assumed to consist of an ensemble of many thin magnetic flux tubes with randomly distributed plasma properties. Each magnetic flux tube in the ensemble is modelled as axisymmetric, non-interacting, vertically oriented and untwisted.

Results. We find that the magnitude and the form of the absorption coefficient is sensitive to the plasma-β of the tubes which is consistent with previous work. Both the random distribution used to model the ensemble of flux tubes and the spatial weighting function inherent to the measurement of the absorption affect the absorption. As the width of the weighting function increases, the absorption increases.