Letter to the Editor
Hinode EUV spectroscopic observations of coronal oscillations
SP2RC, Department of Applied Mathematics, University of Sheffield, Sheffield, S3 7RH, UK e-mail: [robertus;y.taroyan]@sheffield.ac.uk
Accepted: 25 August 2008
Context. Waves offer a unique opportunity to understand and diagnose the properties of the solar coronal plasma.
Aims. Hinode/EIS observations are analysed to detect wave and oscillatory motions in the solar corona.
Methods. The EIS observations were carried out using a selection of EUV lines. Hinode/XRT images are taken concurrently.
Results. Two examples of oscillations in active regions are presented. We analysed the evolution of the intensities and Doppler shifts. The Hinode/XRT images suggest that both events occurred along loop-like structures. The first event is interpreted as a slow sausage (acoustic) type wave with a period of 1.2 mHz. The second example is associated with a transverse, most likely kink type, wave with a period of 3 mHz. The EUV line ratios were then used to determine the value of the coronal magnetic field.
Key words: techniques: spectroscopic / Sun: corona / Sun: oscillations / line: profiles / magnetohydrodynamics (MHD)
© ESO, 2008