A&A 386, 653-657 (2002)
Oscillations on the Sun in regions with a vertical magnetic field
I. Sunspot umbral oscillationsV. I. Zhukov
Central Astronomical Observatory of Russian Academy of Sciences, 65 Pulkovo, 196 140 St. Petersburg, Russia
(Received 29 August 2001 / Accepted 29 January 2002 )
We have calculated the spectrum of eigenmodes of umbral oscillations. The eigenmodes of oscillations with periods from several tens of minutes ( g-modes) to several tens of seconds ( p-modes) have been found. It is shown that the 3-min umbral oscillations are p-modes modified by the magnetic field.
Key words: Sun: sunspots -- Sun: oscillations -- magnetohydrodynamics (MHD)
© ESO 2002