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Issue A&A
Volume 440, Number 2, September III 2005
Page(s) L59 - L62
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:200500169



A&A 440, L59-L62 (2005)
DOI: 10.1051/0004-6361:200500169

Letter

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

C. Foullon1, E. Verwichte1, V. M. Nakariakov1 and L. Fletcher2

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.


Key words: Sun: corona -- flares -- oscillations -- X-rays, gamma rays




© ESO 2005


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