Model Calculations of Magnetic Flux Tubes - Part Two - Stationary Results for Solar Magnetic Elements
Based on the methods of a preceding paper (Deinzer et al., 1984) we present models of stationary magnetic flux elements which are thought to build the basic strncture of the solar photospheric magnetic field. The main results are: a) A model with a density reduction to half of the ambient value and a reduction of the vertical convective transport coefficient by a factor 0.2 is well comparable with the semi- empirical model of Chapman (1979). b) The tube is surrounded by a dark region of gas which is significantly cooler than the undisturbed photo sphere at the same height. This reduces the "hot wall effect" and points to the necessity of an additional heating process for the upper layers of the flux tube atmosphere. c) The inclination of the isotherms with respect to the lines of constant gravitational potential in the nonmagnetic surroundings of the tube leads to a downflow around the magnetic strncture with a velocity of ∼ 1 km s-1. d) The energetics of the observable layers (τ ≍ 1) of the tube is dominated by horizontal radiative influx. Convective transport along the tube plays a secondary role.
Astronomy and Astrophysics
- Pub Date:
- October 1984