Speaker
Description
First Name: William
Last Name: Ashfield
Affiliation: Southwest Research Institute
All Authors: William Ashfield, Vanessa Polito, Juraj Lörinčík, Bart De Pontieu, Georgios Chintzoglou, Souvik Bose, Nabil Freij, Luc Rouppe van der Voort, Reetika Joshi, Jonas Thoen Faber
Solar and stellar flares often exhibit oscillations, or quasi-periodic pulsations (QPPs), across the electromagnetic spectrum. While magnetic-field reconnection drives these events, it remains to be determined whether oscillatory reconnection causes the quasi-periodicity, or whether waves drive or mediate this process. Exploiting coordinated observations from NASA’s Interface Region Imaging Spectrograph and the Swedish 1-m Solar Telescope, here we present spectroscopic observations of QPPs in a solar flare at high-temporal (<1 s) and high-spatial (~60 km) resolution. Downwards velocities in the flare ribbon show synchronized oscillations at different atmospheric layers with a period of ~32 s. These velocities correlate with hard X-ray emissions, indicating a modulated deposition of accelerated electrons in the chromosphere as the driver. By negating magnetohydrodynamic sausage modes as the modulator, we demonstrate that repeated reconnection drives the QPPs. The QPP-reconnection relationship established here provides observational benchmarks for reconnection models and diagnostics for probing energy release across astrophysical environments.