BOOTSTRAPPING THE CORONAL MAGNETIC FIELD WITH STEREO: UNIPOLAR POTENTIAL FIELD MODELING
We investigate the recently quantified misalignment of {alpha}{sub mis} {approx} 20{sup 0}-40{sup 0} between the three-dimensional geometry of stereoscopically triangulated coronal loops observed with STEREO/EUVI (in four active regions (ARs)) and theoretical (potential or nonlinear force-free) magnetic field models extrapolated from photospheric magnetograms. We develop an efficient method of bootstrapping the coronal magnetic field by forward fitting a parameterized potential field model to the STEREO-observed loops. The potential field model consists of a number of unipolar magnetic charges that are parameterized by decomposing a photospheric magnetogram from the Michelson Doppler Imager. The forward-fitting method yields a best-fit magnetic field model with a reduced misalignment of {alpha}{sub PF} {approx} 13{sup 0}-20{sup 0}. We also evaluate stereoscopic measurement errors and find a contribution of {alpha}{sub SE} {approx} 7{sup 0}-12{sup 0}, which constrains the residual misalignment to {alpha}{sub NP} {approx} 11{sup 0}-17{sup 0}, which is likely due to the nonpotentiality of the ARs. The residual misalignment angle, {alpha}{sub NP}, of the potential field due to nonpotentiality is found to correlate with the soft X-ray flux of the AR, which implies a relationship between electric currents and plasma heating.
- OSTI ID:
- 21443245
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 140, Issue 3; Other Information: DOI: 10.1088/0004-6256/140/3/723; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
ELECTRIC CURRENTS
FORCE-FREE MAGNETIC FIELDS
GEOMETRY
NONLINEAR PROBLEMS
PLASMA HEATING
POTENTIALS
SIMULATION
SOFT X RADIATION
SOLAR CORONA
SUN
THREE-DIMENSIONAL CALCULATIONS
TOPOLOGY
ULTRAVIOLET RADIATION
ATMOSPHERES
CURRENTS
ELECTROMAGNETIC RADIATION
HEATING
IONIZING RADIATIONS
MAGNETIC FIELDS
MAIN SEQUENCE STARS
MATHEMATICS
RADIATIONS
SOLAR ATMOSPHERE
STARS
STELLAR ATMOSPHERES
STELLAR CORONAE
X RADIATION