AAS Meeting #194 - Chicago, Illinois, May/June 1999
Session 93. Quiet Photosphere, Chromosphere and Transition Region
Display, Thursday, June 3, 1999, 9:20am-4:00pm, Southeast Exhibit Hall

[Previous] | [Session 93] | [Next]

[93.14] Intensity Oscillations in Sunspot Plumes

A. Fludra (Rutherford Appleton Laboratory, UK)

Sunspot plumes are compact features, located close to sunspots and bright in the transition region lines emitted between 1.7 \times 105 and 4\times 105~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 Å\ 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 Å, Ne~V 572.4 Å\ and Ne~VI 562.8 Å\ lines (1.7-4\times 105~K). Inspection of CDS data for several other sunspots shows that all sunspot plumes show the intensity oscillations of the O~V 629.7 Å\ line and other transition region lines in the 1.7-4\times 105~K temperature range.

This work was supported by the United Kingdom PPARC.

If the author provided an email address or URL for general inquiries, it is a s follows:


[Previous] | [Session 93] | [Next]