Magnetic field oscillations in sunspots and active regions

Balthasar, Horst; Collados, Manuel; Muglach, Karin
Bibliographical reference

In: Proceedings of the SOHO 10/GONG 2000 Workshop: Helio- and asteroseismology at the dawn of the millennium, 2-6 October 2000, Santa Cruz de Tenerife, Tenerife, Spain. Edited by A. Wilson, Scientific coordination by P. L. Pallé. ESA SP-464, Noordwijk: ESA Publications Division, ISBN 92-9092-697-X, 2001, p. 163 - 167

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1
2001
Number of authors
3
IAC number of authors
0
Citations
4
Refereed citations
3
Description
In order to investigate the oscillatory behaviour of the magnetic field in sunspots and pores, full Stokes measurements of 1.56 μm iron lines have been performed using the Tenerife Infrared Polarimeter (TIP) at the German Vacuum Tower Telescope on Tenerife. As expected, velocity oscillations have power peaks at five minutes. First results for temporal variations of the magnetic field show that they occur in locally restricted areas in sunspots. Periods in the five minute range are preferred. In addition, we investigate magnetograms taken with the Michelson Doppler Imager (MDI) on SOHO. Intensity images in white light and around 160 nm were obtained with TRACE as well. Intensity power is strongly with TRACE as well. Intensity power is strongly suppressed in the sunspot area, although we find powerpeaks in the five and three minute ranges.