Volume 387, Number 1, May III 2002
|Page(s)||L13 - L16|
|Published online||15 May 2002|
Letter to the Editor
The detection of 3 & 5 min period oscillations in coronal loops
School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, Scotland
2 L3Com Analytics Corp., NASA GSFC, Code 682.3, Bldg. 26, Greenbelt, MD 20771, USA
3 Department of Physics, Astronomy and Maths, University of Central Lancashire, Preston, PR1 2HE, UK
Corresponding author: I. De Moortel, email@example.com
Accepted: 21 March 2002
High cadence, 171 Å, TRACE observations show that outward propagating intensity disturbances are a common feature in large, quiescent coronal loops. These oscillations are interpreted as propagating slow magneto-acoustic waves. Using a wavelet analysis, we found periods of the order of s. However, a careful study of the location of the footpoints revealed a distinct separation between those loops that support oscillations with periods smaller than 200 s and periods larger than 200 s. It was found that loops that are situated above sunspot regions display intensity oscillations with a period of the order of s, whereas oscillations in “non-sunspot” loops show periods of the order of s. We conclude that the observed longitudinal oscillations are not flare-driven but are most likely caused by an underlying driver exciting the loop footpoints. This result suggests that the underlying oscillations can propagate through the transition region and into the corona.
Key words: MHD / Sun: oscillations / corona / sunspots
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.