Abstract
The magnetic field in an axisymmetric pore is current free and can be represented by a flux tube with a magnetic potential of the formAJ 0(kr)e -kz. For a given magnetic flux the field in this pore model is uniquely defined if the magnetic pressure balances the gas pressure at two levels. For models with fluxes of 0.5–3.0 × 1020 mx the surface radius varies from 1100–2700 km (diameters of 3–8 arc-sec) and the Wilson depression is estimated at 200 km. As the flux increases, the field becomes nearly horizontal at the edge of the pore and eventually a penumbra is formed. The distinction between pores and sunspots is investigated; the critical flux is about 1020 Mx, corresponding to a radius of 1500 km.
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Visitor, as a member of the High Altitude Observatory Solar Project, at Sacramento Peak Observatory, Sunspot, N.M., U.S.A.
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Simon, G.W., Weiss, N.O. On the magnetic field in pores. Sol Phys 13, 85–103 (1970). https://doi.org/10.1007/BF00963944
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DOI: https://doi.org/10.1007/BF00963944