From GHz to mHz: A Multiwavelength Study of the Acoustically Active 14 August 2004 M7.4 Solar Flare

TL;DR

This study analyzes the electromagnetic and acoustic signatures of the 14 August 2004 M7.4 solar flare across multiple wavelengths, revealing that even moderate flares can generate sun quakes and linking seismic activity to magnetic loop structures.

Contribution

It introduces a hypothesis connecting the seismic activity of active regions to the heights of coronal magnetic loops and their role in particle precipitation and acoustic emission.

Findings

Detected sun quake from a moderate M7.4 flare.

Linked seismic activity to magnetic loop heights.

Suggested rapid chromospheric heating as a trigger for acoustic emission.

Abstract

We carried out an electromagnetic acoustic analysis of the solar flare of 14 August 2004 in active region AR10656 from the radio to the hard X-ray spectrum. The flare was a GOES soft X-ray class M7.4 and produced a detectable sun quake, confirming earlier inferences that relatively low-energy flares may be able to generate sun quakes. We introduce the hypothesis that the seismicity of the active region is closely related to the heights of coronal magnetic loops that conduct high-energy particles from the flare. In the case of relatively short magnetic loops, chromospheric evaporation populates the loop interior with ionized gas relatively rapidly, expediting the scattering of remaining trapped high-energy electrons into the magnetic loss cone and their rapid precipitation into the chromosphere. This increases both the intensity and suddenness of the chromospheric heating, satisfying the basic conditions for an acoustic emission that penetrates into the solar interior.