The energy flux of MHD wave modes excited by realistic photospheric drivers
Abstract
The mechanism(s) responsible for solar coronal heating are still an unresolved and challenging task. In the framework of 3D numerical modelling of MHD wave excitation and propagation in the strongly stratified solar atmosphere we analyse the mode coupling and estimate the wave energy partition which can be supplied to the upper layers of the solar atmosphere by locally decomposed slow, fast and Alfven modes. These waves are excited by a number of realistic photospheric drivers which are mimicking the random granular buffeting, the coherent global solar oscillations and swirly motion observed in e.g. magnetic bright points. Based on a self-similar approach, a realistic magnetic flux tubes configuration is constructed and implemented in the VALIIIC model of the solar atmosphere. A novel method for decomposing the velocity perturbations into parallel, perpendicular and azimuthal components in 3D geometry is developed using field lines to trace a volume of constant energy flux. This method is used to identify the excited wave modes propagating upwards from the photosphere and to compute the percentage energy contribution of each mode. We have found, that for all cases where torsional motion is present, the main contribution to the flux (60%) is by Alfven wave. In the case of the vertical driver it is found to mainly excite the fast- and slow-sausage modes and a horizontal driver primarily excites the slow kink mode.
- Publication:
-
40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E.847F