2007/11/30 by C. J. Schrijver, Marc L. DeRosa, M. L. DeRosa +19 · 4 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Astrophysics #Computational physics #Coronal loop #Coronal mass ejection #Field (mathematics) #Field line #Flare #Flux (metallurgy) #Geomagnetism and Paleomagnetism Studies #Ionosphere and magnetosphere dynamics #Magnetic field #Physics #Solar and Space Plasma Dynamics #Solar flare #Solar wind #astro-ph
paper · pdf · doi:10.1086/527413
arxiv created 2007/11/30 · openalex publication_date 2008/03/07 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Solar flares and coronal mass ejections are associated with rapid changes in field connectivity and are powered by the partial dissipation of electrical currents in the solar atmosphere. A critical unanswered question is whether the currents involved are induced by the motion of preexisting atmospheric magnetic flux subject to surface plasma flows or whether these currents are associated with the emergence of flux from within the solar convective zone. We address this problem by applying state-of-the-art nonlinear force-free field (NLFFF) modeling to the highest resolution and quality vector-magnetographic data observed by the recently launched Hinode satellite on NOAA AR 10930 around the time of a powerful X3.4 flare. We compute 14 NLFFF models with four different codes and a variety of boundary conditions. We find that the model fields differ markedly in geometry, energy content, and force-freeness. We discuss the relative merits of these models in a general critique of present abilities to model the coronal magnetic field based on surface vector field measurements. For our application in particular, we find a fair agreement of the best-fit model field with the observed coronal configuration, and argue (1) that strong electrical currents emerge together with magnetic flux preceding the flare, (2) that these currents are carried in an ensemble of thin strands, (3) that the global pattern of these currents and of field lines are compatible with a large-scale twisted flux rope topology, and (4) that the ~10 32 erg change in energy associated with the coronal electrical currents suffices to power the flare and its associated coronal mass ejection.