Imaging and Spectral Observations of Quasi-Periodic Pulsations in a Solar Flare

TL;DR

This study analyzes quasi-periodic pulsations in a solar flare across multiple wavelengths, revealing a consistent 4-minute period linked to magnetic reconnection and non-thermal electron acceleration.

Contribution

It provides detailed multi-wavelength observations of QPPs in a solar flare and links them to magnetic reconnection processes, a novel comprehensive analysis of this phenomenon.

Findings

QPPs show a consistent 4-minute period across different emissions.

QPPs originate from the flare ribbon, appearing at the ribbon front.

Spectral data indicate broad line widths and red Doppler velocities during QPP peaks.

Abstract

We explore the Quasi-Periodic Pulsations (QPPs) in a solar flare observed by Fermi Gamma-ray Burst Monitor (GBM), Solar Dynamics Observatory (SDO), Solar Terrestrial Relations Observatory (STEREO), and Interface Region Imaging Spectrograph (IRIS) on 2014 September 10. QPPs are identified as the regular and periodic peaks on the rapidly-varying components, which are the light curves after removing the slowly-varying components. The QPPs display only three peaks at the beginning on the hard X-ray (HXR) emissions, but ten peaks on the chromospheric and coronal line emissions, and more than seven peaks (each peak is corresponding to a type III burst on the dynamic spectra) at the radio emissions. An uniform quasi-period about 4 minutes are detected among them. AIA imaging observations exhibit that the 4-min QPPs originate from the flare ribbon, and tend to appear on the ribbon front. IRIS spectral observations show that each peak of the QPPs tends to a broad line width and a red Doppler velocity at C I, O IV, Si IV, and Fe XXI lines. Our findings indicate that the QPPs are produced by the non-thermal electrons which are accelerated by the induced quasi-periodic magnetic reconnections in this flare.