Plumes and oscillations in the sunspot transition region

¹ Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway e-mail: nils.brynildsen@astro.uio.no; olav.kjeldseth-moe@astro.uio.no
² Max-Planck-Institut für Aeronomie, 37191 Katlenburg-Lindau, Germany e-mail: wilhelm@linmpi.mpg.de

Corresponding author: P. Maltby, per.maltby@astro.uio.no

Received: 23 February 2001
Accepted: 23 April 2001

Abstract

The suggestion that sunspot transition region oscillations are a typical feature of the sunspot plumes is examined. The present observations show 3 min oscillations in the umbra that end at the umbral rim. We find that sunspot plumes located above the umbra show these oscillations, in contrast to plumes above the penumbra. These two findings suggest that the oscillations may be a property of the umbral transition region.