Understanding the Plasma and Magnetic Field Evolution of a Filament Using Observations and Nonlinear Force-free Field Modeling

Yardley., Stephanie L. and Savcheva, Antonia and Green, Lucie M. and Van Driel Gesztelyi, Lídia and Long, David (2019) Understanding the Plasma and Magnetic Field Evolution of a Filament Using Observations and Nonlinear Force-free Field Modeling. ASTROPHYSICAL JOURNAL, 887. ISSN 1538-4357

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Abstract

We present observations and magnetic field models of an intermediate filament present on the Sun in 2012 August, associated with a polarit inversion line that extends from AR 11541 in the east into the quiet Su at its western end. A combination of Solar Dynamics Observator (SDO)/Atmospheric Imaging Assembly, SDO/Helioseismic and Magnetic Image (HMI), and Global Oscillation Network Group Hα data allow us to analyz the structure and evolution of the filament from 2012 August 4 23:00 U to 2012 August 6 08:00 UT when the filament was in equilibrium. B applying the flux rope insertion method, nonlinear force-free fiel models of the filament are constructed using SDO/HMI line-of-sigh magnetograms as the boundary condition at the two times given above Guided by observed filament barbs, both modeled flux ropes are spli into three sections each with a different value of axial flux t represent the nonuniform photospheric field distribution. The flux i the eastern section of the rope increases by 4 × 1020 M between the two models, which is in good agreement with the amount o flux canceled along the internal PIL of AR 11541, calculated to be 3.2 1020 Mx. This suggests that flux cancellation builds flu into the filament’s magnetic structure. Additionally, the number o field line dips increases between the two models in the locations wher flux cancellation, the formation of new filament threads, and growth o the filament is observed. This suggests that flux cancellatio associated with magnetic reconnection forms concave-up magnetic fiel that lifts plasma into the filament. During this time, the free magneti energy in the models increases by 0.2 × 1031 ergs

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