A sunspot model for study of discrete Alfven waves and instabilities
Abstract
We present a model for sunspots where both the umbral and the penumbral regions are considered. The equilibrium configuration is described by a two-plasma vertical cylindrical model with an axial current. Twisted magnetic fields, with a small B(theta)/B(z) are assumed. Using the ideal magnetohydrodynamics (MHD) model, the analysis of discrete Alfven modes and instabilities is based on the numerical investigation of the Hain-Lust equation. The period of the discrete Alfven mode is found to present the same order of magnitude of those observed for running penumbral waves. Good prediction of the sunspot lifetime can also be obtained.
- Publication:
-
Conference Paper
- Pub Date:
- January 1994
- Bibcode:
- 1994uecb.conf.....O
- Keywords:
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- Sunspots;
- Magnetohydrodynamic Waves;
- Magnetohydrodynamics;
- Magnetic Fields;
- Magnetic Field Configurations;
- Mathematical Models;
- Plasma Equilibrium;
- Pressure Effects;
- Penumbras;
- Solar Physics