Siphon Flows in Isolated Magnetic Flux Tubes
Abstract
Previous studies of siphon flows in magnetic flux tubes have been limited to the case of a low-β plasma, appropriate for an embedded flux tube in the solar corona or chromosphere. Here the author studies steady siphon flows in isolated, thin magnetic flux tubes surrounded by field-free gas, with plasma β ≥ 1, appropriate for conditions in the solar photosphere. The author presents the basic equations governing steady siphon flows in a thin, isolated magnetic flux tube, and discusses the case of a purely horizontal flux tube, for which gravitational forces do not come into play. Qualitative features of isothermal flows in elevated, arched flux tubes are then studied. The author presents the results of some numerical computations of isothermal siphon flows in arched flux tubes and discusses the nature of critical flows and the need for standing "tube shocks" in these flows. Finally, he discusses applications to intense magnetic flux tubes in the solar photosphere and considers the possible interpretation of the Evershed flow in the penumbral photosphere of a sunspot as a siphon flow along isolated magnetic flux tubes.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 1988
- DOI:
- 10.1086/166756
- Bibcode:
- 1988ApJ...333..407T
- Keywords:
-
- Flow Velocity;
- Magnetic Flux;
- Magnetohydrodynamic Waves;
- Solar Atmosphere;
- Solar Corona;
- Steady Flow;
- Acoustic Velocity;
- Computational Astrophysics;
- Critical Flow;
- Siphoning;
- Solar Physics;
- HYDROMAGNETICS;
- PLASMAS;
- SUN: ATMOSPHERIC MOTIONS;
- SUN: SUNSPOTS