Letter to the Editor

X-ray quasi-periodic pulsations in solar flares as magnetohydrodynamic oscillations

¹ Department of Physics, University of Warwick, Coventry CV4 7AL, UK e-mail: foullonc@astro.warwick.ac.uk
² Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK

Received: 21 June 2005
Accepted: 2 August 2005

Abstract

We report the first observation at high spatial resolution of long-period quasi-periodic pulsations (QPP) of X-ray radiation during solar flares, made possible with the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), supported by complementary data at other wavelengths from space-based and ground-based telescopes. Evidence for the presence of a transequatorial loop possibly responsible for the detected periodicity connected with its kink mode is found. Our findings suggest that QPP can be interpreted as a periodic pumping of electrons in a compact flaring loop, modulated by oscillations in a magnetically linked and larger loop acting as a long-period magnetohydrodynamic resonator.