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H. Uitenbroek, K.S. Balasubramaniam (NSO/Sac Peak)
Narrow-band filter imaging in the G band at 430 nm has been used to track the evolution of small-scale magnetic field elements for more than two decades. Because of the presence of many lines of the CH molecule, and the relatively high contrast at this short wavelength the G-band region is exceptionally suitable for this task. Howeve, despite the frequent use of G-band brightness as magnetic field proxy it has not yet been well established what the precise mechanism is that makes the small scale magnetic elements appear bright. In particular, it is unclear why there is no one-to-one correlation between magnetic field and G-band brightness, as has been established from co-spatial magnetograms in atomic lines.
To obtain a better understanding of the elusive G-band brightening mechanism we obtained high spatial- and spectral resolution spectra of the G-band region in Stokes I and V at the Dunn Solar Telescope on Sacramento Peak. We use the molecular Zeeman effect to determine line-of-sight magnetic field strength directly in the CH lines that provide most of the opacity in the G band, avoiding difficulties with co-aligning images and magnetograms taken seperately. We compare our observations with radiative transfer modeling of the Stokes profiles in snapshots of a magneto-hydrodynamic simulation of solar convection.
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The author(s) of this abstract have provided an email address for comments about the abstract: huitenbroek@nso.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.