Magnetoacoustic Waves in Sunspots

Khomenko, E. V.; Collados, M.; Bellot Rubio, L. R.
Referencia bibliográfica

The Astrophysical Journal, Volume 588, Issue 1, pp. 606-619.

Fecha de publicación:
5
2003
Número de autores
3
Número de autores del IAC
1
Número de citas
37
Número de citas referidas
33
Descripción
Observed variations of the magnetic field strength in sunspot umbrae consist of intrinsic oscillations and ``false'' oscillations due to time-dependent opacity effects. Here we present an approach intended for the separation of these components. We develop a mathematical formalism based on the analytical solution of the MHD equations including gravity, inclination of the magnetic field, and effects of nonadiabaticity. The theoretical results are compared with observations in the near-infrared at 1.56 μm by Bellot Rubio and coworkers using the Tenerife Infrared Polarimeter. It is shown that part of the detected field strength variations can be intrinsic magnetic field oscillations caused by magnetoacoustic waves.