Astrophysical: Sunspots

  • Publication
    Magnetic aspects of the evolution of sunspots
    The spectroscopic determinations of the solar magnetic fields are based on the Zeeman effect observed in relation to a number of absorption lines of the solar...
  • Publication
    Magnetic field fluctuations in the shocked umbral chromosphere
    Context. Umbral chromospheric observations show the presence of magnetoacoustic shocks. Several recent studies have reported magnetic field fluctuations...
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    Magnetic field oscillations in sunspots and active regions
    In order to investigate the oscillatory behaviour of the magnetic field in sunspots and pores, full Stokes measurements of 1.56 μm iron lines have been...
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    Magnetic fields of opposite polarity in sunspot penumbrae
    Context. A significant part of the penumbral magnetic field returns below the surface in the very deep photosphere. For lines in the visible, a large portion of...
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    Magnetic Flux Cancellation in the Moat of Sunspots: Results from Simultaneous Vector Spectropolarimetry in the Visible and the Infrared
    We analyze multiwavelength observations of the cancellation of a moving magnetic feature and a plage element at the outer edge of the moat of an isolated, round...
  • Publication
    Magneto-acoustic Waves in Sunspots: First Results From a New Three-dimensional Nonlinear Magnetohydrodynamic Code
    Waves observed in the photosphere and chromosphere of sunspots show complex dynamics and spatial patterns. The interpretation of high-resolution sunspot wave...
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    Magnetoacoustic Wave Energy from Numerical Simulations of an Observed Sunspot Umbra
    We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through three-dimensional MHD numerical...
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    Magnetoacoustic Waves in Sunspots
    Observed variations of the magnetic field strength in sunspot umbrae consist of intrinsic oscillations and ``false'' oscillations due to time-dependent opacity...
  • Publication
    Magnetohydrostatic Sunspot Models from Deep Subphotospheric to Chromospheric Layers
    In order to understand the influence of magnetic fields on the propagation properties of waves, as derived from different local helioseismology techniques...