Discussion paper: The eigen oscillations of the solar active regions

Abstract

[1]  The standing MHD-waves in the potential magnetic arcades describing the bipolar active regions are investigated. The eikonal method allows us the analytical study of the short waves which are divided into the Alfvén and magnetosonic waves. The eigen modes of the magnetic arcades are formed as a result of their reflection from the photosphere. The Alfvén mode oscillations of the certain frequency take place on the magnetic surfaces. The fast mode oscillations also take place on some surfaces but they are not magnetic. Each oscillation surface has a discrete set of the eigen frequencies.

Received 11 April 2006; accepted 9 August 2006; published 24 February 2007.

Keywords: Solar active regions; Eigen oscillations; Magnetic arcades.

Index Terms: 7524 Solar Physics, Astrophysics, and Astronomy: Magnetic fields; 7836 Space Plasma Physics: MHD waves and instabilities; 7509 Solar Physics, Astrophysics, and Astronomy: Corona.