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arXiv · 1503.02741

Estimating electric current densities in solar active regions

M. S. Wheatland
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Abstract

Electric currents in solar active regions are thought to provide the energy released via magnetic reconnection in solar flares. Vertical electric current densities $J_z$ at the photosphere may be estimated from vector magnetogram data, subject to substantial uncertainties. The values provide boundary conditions for nonlinear force- free modelling of active region magnetic fields. A method is presented for estimating values of $J_z$ taking into account uncertainties in vector magnetogram field values, and minimizing $J_z^2$ across the active region. The method is demonstrated using the boundary values of the field for a force-free twisted bipole, with the addition of noise at randomly chosen locations.

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M. S. Wheatland. 2015-03-10. Estimating electric current densities in solar active regions. https://doi.org/10.1007/s11207-015-0672-5

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