Solar Physics

, Volume 148, Issue 1, pp 65–84 | Cite as

The temperature variation across the boundary of dark spots on the solar surface

  • Detlev Degenhardt
Article
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Abstract

We suppose the transport of energy in a sunspot (or pore) is described by a diffusion process. The thermal conductivities in the spot and its surroundings are assumed to be constant and isotropic, but with a reduced conductivity in the spot. The sunspot and the ambient medium are represented by semi-infinite strips of variable depth, with one common boundary. This interface is a plane inclined at an arbitrary angle with respect to the vertical in order to simulate the inclined magnetic field at the umbral/penumbral, penumbral/photospheric or pore/photospheric 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 umbral surface in a region near the boundary, resulting in a decreased temperature contrast across the surface. The thermal disturbance in the neighboring medium is confined to a very small region.

Keywords

Magnetic Field Thermal Conductivity Surface Layer Temperature Variation Diffusion Process 
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Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Detlev Degenhardt
    • 1
    • 2
  1. 1.High Altitude ObservatoryNational Center for Atmospheric ResearchBoulderUSA
  2. 2.Universitäts-SternwarteGöttingenGermany

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