THE TEMPERATURE-VARIATION ACROSS THE BOUNDARY OF DARK SPOTS ON THE SOLAR SURFACE

We suppose the transport of energy in a sunspot (or pore) is described by a diffusion process. The thermal conductivities in the spot and it s surroundings are assumed to be constant and isotropic, but with a re duced conductivity in the spot. The sunspot and the ambient medium are . represented by semi-infinite strips of variable depth, with one comm on boundary. This interface is a plane inclined at an arbitrary angle with respect to the vertical in order to simulate the inclined magneti c field at the umbral/penumbral, penumbral/photospheric or pore/photos pheric boundary. We show that the region with high conductivity below the interface produces a thermal disturbance in the surface layers of the umbra which manifests itself as a temperature enhancement at the u mbral surface in a region near the boundary, resulting in a decreased temperature contrast across the surface. The thermal disturbance in th e neighboring medium is confined to a very small region.