Bibcode
                                    
                            Jurčák, J.; Bello González, N.; Schlichenmaier, R.; Rezaei, R.
    Referencia bibliográfica
                                    Astronomy and Astrophysics, Volume 597, id.A60, 4 pp.
Fecha de publicación:
    
                        12
            
                        2016
            
  Revista
                                    
                            Número de citas
                                    0
                            Número de citas referidas
                                    0
                            Descripción
                                    Context. We recently presented evidence that stable umbra-penumbra
boundaries are characterised by a distinct canonical value of the
vertical component of the magnetic field,
Bstablever. In order to trigger the formation of a
penumbra, large inclinations in the magnetic field are necessary. In
sunspots, the penumbra develops and establishes by colonising both
umbral areas and granulation, that is, penumbral magneto-convection
takes over in umbral regions with
Bver