Detections of high-frequency oscillations in solar active region coronal loops

One of the mechanisms proposed as a possible solution to the Sun's coronal heating problem is the damping of energy carried by magnetohydrodynamic (MHD) waves that are expected to be present in active regions. Continuing previous work on total solar eclipse data, we provide further observational evidence for the existence of high-frequency MHD waves in coronal loops. Wavelet analysis is used to identify 21 areas of 4 x 4 arcsec(2) with periodic intensity oscillations. The frequency range of these detections was 0.2-0.3 Hz and all last for at least 3 periods at a confidence level of more than 99%. All of the above detections are made just outside known coronal loops, leading us to suggest a possible, unconventional mechanism.