Similarities and differences between solar and stellar flare pulsation processes

TL;DR

This review compares solar and stellar flare pulsations, highlighting their similarities, differences, and underlying physical mechanisms, and emphasizes the continuity of magnetic activity across different astrophysical scales.

Contribution

It provides a comprehensive comparison of QPPs in solar and stellar flares, revealing common scaling relations and physical processes, and linking solar physics to stellar magnetic activity.

Findings

Solar and stellar QPPs share similar physical mechanisms.

Stellar QPPs have longer periods, from minutes to hours.

Both types of QPPs follow common scaling relations.

Abstract

Quasi-periodic pulsations (QPPs) are oscillatory signatures commonly detected in the light curves of solar and stellar flares, offering valuable diagnostics of the underlying magnetic and plasma processes. This review compares the observational characteristics, detection methods, and physical interpretations of QPPs in both solar and stellar contexts. Solar flare QPPs, extensively studied in X-rays and EUV bands using instruments such as GOES, STIX, and Fermi, display typical periods of tens of seconds and show correlations with flare duration and magnetic loop length. Stellar QPPs, observed in X-rays and white light by missions such as Kepler, TESS, and XMM-Newton, exhibit much longer periods - ranging from minutes to hours - consistent with larger-scale magnetic structures in more active stars. Despite differences in scale and observing band, statistical and comparative studies reveal common scaling relations and damping behaviors, suggesting that both solar and stellar QPPs are manifestations of the same fundamental mechanisms, likely magnetohydrodynamic oscillations or oscillatory reconnection within flare loops. The comparison underscores a continuity between solar and stellar magnetic activity, linking the solar detailed physical processes to stellar-scale phenomena and providing constraints for future models and surveys.