Coronal oscillations in the vicinity of a sunspot as observed by GIS/CDS

Abstract

We present the analysis and results of GIS time series observed on 19th July 2003 at the boundary between the quiet Sun and an active region, close to a sunspot. The velocity map of NIS/CDS O v 629 Å show two pairs of red and blue shifts surrounding the brightest region. Presumably, we have observed coronal loops with opposite flow velocities. Although our observations were not taken directly at the sunspot, the 3-min oscillations are seen in several coronal spectral lines. Thus the coronal loops can have some connection with the sunspot, in the vicinity. We report here of oscillations in these coronal loops as observed with coronal lines formed around 1MK or higher. Further more, the oscillations form wave packets and are intermittent with no obvious decay. The average time scale of the intermittence is of the order of 20minutes.