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Author Yeates, Anthony R.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ASSIMILATION ♦ ELECTRIC FIELDS ♦ EVOLUTION ♦ MAGNETIC FIELDS ♦ MAGNETOHYDRODYNAMICS ♦ PHOTOSPHERE ♦ SPHERICAL CONFIGURATION ♦ SUN ♦ SURFACES ♦ TIME DEPENDENCE
Abstract Accurate estimates of the horizontal electric field on the Sun’s visible surface are important not only for estimating the Poynting flux of magnetic energy into the corona but also for driving time-dependent magnetohydrodynamic models of the corona. In this paper, a method is developed for estimating the horizontal electric field from a sequence of radial-component magnetic field maps. This problem of inverting Faraday’s law has no unique solution. Unfortunately, the simplest solution (a divergence-free electric field) is not realistically localized in regions of nonzero magnetic field, as would be expected from Ohm’s law. Our new method generates instead a localized solution, using a basis pursuit algorithm to find a sparse solution for the electric field. The method is shown to perform well on test cases where the input magnetic maps are flux balanced in both Cartesian and spherical geometries. However, we show that if the input maps have a significant imbalance of flux—usually arising from data assimilation—then it is not possible to find a localized, realistic, electric field solution. This is the main obstacle to driving coronal models from time sequences of solar surface magnetic maps.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2017-02-10
Publisher Place United States
Journal Astrophysical Journal
Volume Number 836
Issue Number 1


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