Sunquake Generation by Coronal Magnetic Restructuring

Abstract

Sunquakes are the surface signatures of acoustic waves in the Sun's interior that are produced by some but not all flares and coronal mass ejections (CMEs). This paper explores a mechanism for sunquake generation by the magnetic field changes that occur during flares and CMEs, using MHD simulations with a semiempirical FAL-C atmosphere to demonstrate the generation of acoustic waves in the interior in response to changing magnetic tilt in the corona. We find that Alfven-sound resonance combined with the ponderomotive force produces acoustic waves in the interior with sufficient energy to match sunquake observations when the magnetic field angle changes by the order of 10 degrees in a region where the coronal field strength is a few hundred gauss or more. The most energetic sunquakes are produced when the coronal field is strong, while the variation of magnetic field strength with height and the time scale of the tilt change are of secondary importance.

6 pages, 3 figures; accepted to ApJ

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• Investigation of Relationship Between High-Energy X-ray Sources and Photospheric and Helioseismic Impacts of X1.8 Solar Flare of October 23, 2012
• Sunquakes of Solar Cycle 24
• The Chromospheric Response to the Sunquake generated by the X9.3 Flare of NOAA 12673
• Alfvén Waves in Solar Flares
• Time path of turbulence and multi-fractality of magnetic field in the evolution of an active region