Superpenumbral vortices
Abstract
Spectroheliograms, especially in Hα, often show vortex structures in the superpenumbral area of a sunspot, which covers a region from the outer boundary of the spot to about five spot radii. Attempts were made at the beginning of this century to understand the physics of these solar vortices, but pure hydrodynamical or electrodynamical theories failed. The model presented in this paper is based on simplified magnetohydrodynamic equations. The assumptions chosen render an analytical solution practicable, and an obvious explanation for this long-standing problem is obtained. Although this magnetohydrodynamic theory is accomplished in a simple way, it is able to reproduce the main facts of the statistical observations and quantitative measurements.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 1996
- DOI:
- 10.1093/mnras/278.3.821
- Bibcode:
- 1996MNRAS.278..821P
- Keywords:
-
- MHD;
- SUN: CHROMOSPHERE;
- SUNSPOTS