Relationship between wave processes in sunspots and quasi-periodic pulsations in active region flares

TL;DR

This paper investigates the link between sunspot oscillations and quasi-periodic pulsations in solar flares, showing that 3-minute waves from sunspots can trigger flare pulsations via coronal loops.

Contribution

It establishes a phenomenological relationship and suggests that 3-minute sunspot oscillations can induce flare pulsations through wave leakage along coronal loops.

Findings

Increase in 3-min oscillation power before flares

Flares exhibit bursty 3-min periodicity

Oscillations propagate along coronal loops to flare sites

Abstract

A phenomenological relationship between oscillations in a sunspot and quasi-periodic pulsations in flaring energy releases at an active region above the sunspot, is established. The analysis of the microwave emission recorded by the Nobeyama Radioheliograph at 17 GHz shows a gradual increase in the power of the 3-min oscillation train in the sunspot associated with AR 10756 before flares in this active region. The flaring light curves are found to be bursty with a period of 3 min. Our analysis of the spatial distribution of the 3-min oscillation power implies that the oscillations follow from sunspots along coronal loops towards the flaring site. It is proposed that quasi-periodic pulsations in the flaring energy releases can be triggered by 3-min slow magnetoacoustic waves leaking from sunspots.