Plasma Motions and Turbulent Magnetic Diffusivity of Active Region AR 12158 Using a Minimum Energy Functional and Non-Force-Free Reconstructions of Vector Magnetograms

详细信息    查看全文

• 作者：Benoit Tremblay ; Alain Vincent
• 关键词：Magnetic fields ; photosphere ; Velocity fields ; photosphere ; Active regions ; Granulation
• 刊名：Solar Physics
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：292
• 期：1
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Astrophysics and Astroparticles; Atmospheric Sciences; Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics);
• 出版者：Springer Netherlands
• ISSN：1573-093X
• 卷排序：292

文摘

We present a generalization of the resistive minimum-energy fit (MEF-R: Tremblay and Vincent, Solar Phys.290, 437, 2015) for non-force-free (NFF) magnetic fields. In MEF-R, an extremum principle is used to infer two-dimensional maps of plasma motions [\(\boldsymbol{v}(x,y)\)] and magnetic eddy diffusivity [\(\eta _{\mathrm{eddy}}(x,y)\)] at the photosphere. These reconstructions could be used as boundary conditions in data-driven simulations or in data assimilation. The algorithm is validated using the analytical model of a resistive expanding spheromak by Rakowski, Laming, and Lyutikov (Astrophys. J.730, 30, 2011). We study the flaring Active Region AR 12158 using a series of magnetograms and Dopplergrams provided by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). The results are discussed for a non-force-free magnetic-field reconstruction [\(\boldsymbol{B}_{\mathrm{NFF}}\)] (Hu and Dasgupta in Solar Phys.247, 87, 2008). We found that the vertical plasma velocities [\(v_{z}(x,y)\)] inferred using MEF-R are very similar to the observed Doppler velocities [\(v_{r}(x,y)\)]. Finally, we study the potential spatial correlation between microturbulent velocities and significant values of \(\eta_{\mathrm{eddy}}(x,y)\).