Observations of simultaneous coronal loop shrinkage and expansion during the decay phase of a solar flare
Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, UK e-mail: firstname.lastname@example.org
2 Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street, Palo Alto, CA 94304, USA
Accepted: 9 March 2006
We report what we believe are the first direct and unambiguous observations of simultaneous coronal magnetic flux loop shrinkage and expansion during the decay phase of a solar flare. The retracting and expanding loops were observed nearly face-on (i.e., with the loop major axis approximately orthogonal to the line of sight) in emission in imaging data from the Yohkoh Soft X-ray Telescope (SXT). The retracting loop is observed to shrink with a speed of 118 ± 66 km s-1. The faint outward moving loop-like feature occurred ~200´´ above the shrinking loop during the time of the shrinking loop. We estimate the speed of the outward moving loop was ~129 ± 74 km s-1. We interpret the shrinking loop and simultaneous outward moving loop as direct evidence for reconnected magnetic field lines during a flare.
Key words: Sun: corona / Sun: flares / Sun: magnetic fields / Sun: X-rays, gamma rays / magnetohydrodynamics (MHD)
© ESO, 2006