A NUMERICAL-SIMULATION OF 2-DIMENSIONAL RADIATIVE EQUILIBRIUM IN MAGNETOSTATIC FLUX TUBES .2. COMPUTATIONAL RESULTS

We apply a recently developed numerical procedure for obtaining self-c onsistent radiative and mechanical equilibria of solar magnetostatic f lux tubes. The tubes are modeled as localized but continuous field con centrations in a two-dimensional slab geometry, and the radiation is t reated in the LTE limit. The reduced opacities in the tube (stemming f rom the lower gas pressures required for mechanical force balance) lea d to the lateral intrusion of radiative flux into the tube, with subse quent modification of the internal atmosphere. Our calculations show t hat the effect is negligible, however, when the diameter of the tube e xceeds the scale height of the atmosphere in the surface layers (d gre ater than or similar to 100 km) or if convective energy transport in t he tube is itself sufficient to produce a thermal stratification close to that in the surrounding photosphere. That is, two-dimensional radi ative effects are likely to be important only in small tubes in which the upward convective energy flux is strongly suppressed. The treatmen t of the underlying convective layers appears to be of paramount impor tance in determining the computed surface properties.