A Siphon-Flow Model of the Photospheric Evershed Flow in a Sunspot
Abstract
The Evershed flow at photospheric heights in a sunspot penumbra is modeled theoretically as a siphon flow along individual, arched magnetic flux tubes embedded in an atmosphere permeated by a uniform magnetic field. This approach is suggested by the recent evidence that the penumbra is a deep structure with a significant amount of emerging flux, rather than a shallow structure overlying field-free gas. The model resolves two problems associated with siphon-flow models based on a shallow penumbra: it produces arched flux tubes of sufficient horizontal extent, and it explains how the optically thin flux tubes carrying the Evershed flow can appear dark.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1993
- DOI:
- 10.1086/172522
- Bibcode:
- 1993ApJ...407..398T
- Keywords:
-
- Penumbras;
- Photosphere;
- Solar Magnetic Field;
- Solar Physics;
- Sunspots;
- Solar Atmosphere;
- Stellar Models;
- Solar Physics;
- MAGNETOHYDRODYNAMICS: MHD;
- SUN: SUNSPOTS