Sunquakes of Solar Cycle 24

TL;DR

This study analyzes helioseismic events caused by solar flares during Solar Cycle 24, revealing that sunquakes are more associated with flare impulsiveness and high-energy particles than with flare magnitude.

Contribution

It introduces a new catalog of helioseismic solar flares and demonstrates that sunquake strength correlates better with X-ray flux derivatives than with flare class.

Findings

Many strong sunquakes are produced by low M-class flares.

Sunquake power correlates with the maximum of the X-ray flux time derivative.

Seismically active flares tend to be more impulsive.

Abstract

The paper presents results of a search for helioseismic events (sunquakes) produced by M-X class solar flares during Solar Cycle 24. The search is performed by analyzing photospheric Dopplergrams from Helioseismic Magnetic Imager (HMI). Among the total number of 500 M-X class flares, 94 helioseismic events were detected. Our analysis has shown that many strong sunquakes were produced by solar flares of low M class (M1-M5), while in some powerful X-class flares helioseismic waves were not observed or were weak. Our study also revealed that only several active regions were characterized by the most efficient generation of helioseismic waves during flares. We found that the sunquake power correlates with the maximum value of the soft X-ray flux time derivative better than with the X-ray class, indicating that the sunquake mechanism is associated with high-energy particles. We also show that the seismically active flares are more impulsive than the flares without helioseismic perturbations. We present a new catalog of helioseismic solar flares, which opens opportunities for performing statistical studies to better understand the physics of sunquakes as well as the flare energy release and transport.