Radiative Damping of Coronal-Loop Oscillations

A theoretical interpretation is given to the coronal-loop oscillations that have been recently detected by the UV telescope of the TRACE spacecraft. It is shown that the anomalously rapid damping of coronal-loop oscillations initiated by an external action (a shock wave from a solar flare) is completely explained in terms of the radiative damping mechanism. A coronal loop oscillating with a small but finite (observable) amplitude in an external magnetic field efficiently generates fast magnetosonic modes. As a result, the perturbation energy is completely dissipated during several periods of free oscillations of the loop. The problem is studied in the perfectly conducting plasma approximation. The effect is explained without making any hypotheses about anomalous properties of the plasma inside the coronal loops.