8-12 juin, 2014

Résumé

MEF-R: Computing Photospheric Velocity Fields and Eddy Magnetic Diffusivities Using Vector Magnetograms and Dopplergrams

Benoit Tremblay (Université de Montréal)

Alain Vincent (Département de physique, Université de Montréal)

We have developed a generalization of the Minimum Energy Fit (MEF) algorithm (Longcope, 2004) to include an eddy magnetic diffusivity at the Sun's surface which accounts for the effects of subgrid fluctuations. The Resistive Minimum Energy Fit (MEF-R) uses reconstructed vector magnetograms and Dopplergrams as input to infer photospheric velocity fields and eddy magnetic diffusivities consistent with the resistive magnetic induction equation and which minimize an energy-like functional. Applications of the method are currently limited to the linear force-free magnetic field approximation (LFFF) though the MEF-R formalism holds for non force-free magnetic fields. The inferred vertical velocities are close to the observed Doppler velocities. The resulting eddy diffusivity could be used for subgrid scale modeling of photospheric flows.

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