3.3 Penumbral modeling

The previous section stresses the point that the penumbra is a phenomenon of complex interaction of magneto-convective forces and radiation in a regime of inclined magnetic field of intermediate strength. One simplified view on this problem is to consider a separation between convective plumes and a magnetic configuration as it is done in the field-free gap model. Another simplified view is by dealing with the problem in ideal MHD, in which the thin flux tube approximation is applicable. The latter perspective is taken in the siphon flow model and the dynamic extension of it, the moving tube model. Yet, for a full understanding it seems necessary to take into account dissipative magneto-convection driven by radiation. But we want to stress that simplified models often help to isolate the dominating physical processes, and to understand the essentials.
  Go to previous page Go up Go to next page