Intensity Oscillations in Sunspot Plumes
Abstract
Sunspot plumes are compact features, located close to sunspots and bright in the transition region lines emitted between 1.7 x 10(5) and 4x 10(5) K. Observations of a sunspot plume in the active region AR8249 have been made with the Coronal Diagnostic Spectrometer (CDS) on SOHO with a 15-second time resolution. We report the finding of intensity oscillations of the O V 629.7 Angstroms line in the sunspot plume, with an amplitude up to 10 percent. Fourier analysis gives two periods of 167 and 182 seconds. Oscillations are also seen in the Ne IV 543.9 Angstroms , Ne V 572.4 Angstroms and Ne VI 562.8 Angstroms lines (1.7-4x 10(5) K). Inspection of CDS data for several other sunspots shows that all sunspot plumes show the intensity oscillations of the O V 629.7 Angstroms line and other transition region lines in the 1.7-4x 10(5) K temperature range. This work was supported by the United Kingdom PPARC.
- Publication:
-
American Astronomical Society Meeting Abstracts #194
- Pub Date:
- May 1999
- Bibcode:
- 1999AAS...194.9314F