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A. A. Norton, P. A. Gilman (High Altitude Observatory, NCAR)
We are interested in what solar surface magnetism can tell us about the interior toroidal magnetic fields. Because some fraction of solar surface magnetism must be a direct result of the dynamics of the interior toroidal field, we feel it is worthwhile to study the patterns of flux which emerge and attempt to recover the basic properties of the toroidal bands and their time dependent behavior.
New theory predicts a global instability resulting in a tipping of the toroidal bands with respect to the equatorial plane. We search for evidence of a tipped toroidal field for some phases of the solar cycle by examining the dominant latitude of emerging flux as a function of longitude. In order to determine the extent to which we can recover the toroidal field dynamics from observations, we use a model to artificially generate sunspot distributions from subsurface toroidal fields that we have assigned certain properties such as latitudinal width, peak field strength and degree of tipping with respect to the equatorial plane. Observational studies set an upper limit of 15 degrees to the tipping angle. Model results which best fit the observed data are those having a toroidal band with a tipping angle of 10 degrees at high latitudes (early in the sunspot cycle) gradually decreasing to 0 degrees as the sunspot band migrates towards the equator.
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Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.