Detections of Multi-Periodic Oscillations during a Circular Ribbon Flare

TL;DR

This study analyzes multi-wavelength observations of a circular-ribbon solar flare, identifying three types of oscillations with different periods, which shed light on the physical mechanisms driving flare dynamics.

Contribution

It reports the first detailed observation of three distinct oscillation types during a circular-ribbon flare, linking thermal and nonthermal processes and suggesting possible wave and reconnection origins.

Findings

Detected a 20-second QPP in X-ray, EUV, and microwave emissions.

Identified 72-second periodic jets likely caused by magnetic reconnection.

Observed a 168-second outer loop perturbation possibly triggered by a blast wave.

Abstract

We present the analysis of three kinds of oscillating behavior using multi-wavelength observations of the 10 November 2013 (SOL2013-11-10T05:14) circular-ribbon flare. This event is a typical circular-ribbon flare with an outer spine structure and homologous jets. We found three kinds of oscillations (or perturbations): i) flux oscillation (or QPP) with a dominant period of about 20 seconds in X-ray, EUV, and microwave emissions, ii) periodic jets with an intermittent cadence of around 72 seconds, iii) an outer loop perturbing half a cycle with a duration of about 168 seconds. Similar to the periodic jets that could be produced by a nonthermal process, like repeated magnetic reconnection, the flare QPP detected in the thermal emissions could have the same origin as the oscillation seen in the nonthermal emissions. The outer-loop perturbation is possibly triggered by a blast wave driven by the circular-ribbon flare, or it might be modulated by the sausage wave or the slow magnetoacoustic wave. The results obtained provide data for further numerical studies on the physical origin of the flare oscillations.