A Ring of Polarized Light: Evidence for Twisted Coronal Magnetism in Cavities

Coronal prominence cavities may be manifestations of twisted or sheared magnetic fields capable of storing the energy required to drive solar eruptions. The Coronal Multi-Channel Polarimeter (CoMP), recently installed at Mauna Loa Solar Observatory, can measure polarimetric signatures of current-car...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2011-04, Vol.731 (1), p.L1-jQuery1323917904989='48'
Main Authors: Dove, J. B, Gibson, S. E, Rachmeler, L. A, Tomczyk, S, Judge, P
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
ATMOSPHERES
ELECTROMAGNETIC RADIATION
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC FLUX
MAGNETISM
MAGNETOHYDRODYNAMICS
MECHANICS
POLARIZATION
RADIATIONS
RINGS
SOLAR ATMOSPHERE
SOLAR CORONA
STELLAR ATMOSPHERES
STELLAR CORONAE
VISIBLE RADIATION
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Summary:Coronal prominence cavities may be manifestations of twisted or sheared magnetic fields capable of storing the energy required to drive solar eruptions. The Coronal Multi-Channel Polarimeter (CoMP), recently installed at Mauna Loa Solar Observatory, can measure polarimetric signatures of current-carrying magnetohydrodynamic (MHD) systems. For the first time, this instrument offers the capability of daily full-Sun observations of the forbidden lines of Fe XIII with high enough spatial resolution and throughput to measure polarimetric signatures of current-carrying MHD systems. By forward-calculating CoMP observables from analytic MHD models of spheromak-type magnetic flux ropes, we show that a predicted observable for such flux ropes oriented along the line of sight is a bright ring of linear polarization surrounding a region where the linear polarization strength is relatively depleted. We present CoMP observations of a coronal cavity possessing such a polarization ring.
ISSN:2041-8205
2041-8213
DOI:10.1088/2041-8205/731/1/L1