Numerical simulations of the CME on 2010 April 8

AbstractWe present 3D zero-beta ideal MHD simulations of the solar flare/CME event that occurred in Active Region 11060 on 2010 April 8. The initial magnetic configurations of the two simulations are stable nonlinear force-free field and unstable magnetic field models constructed by Su et al. (2011) using the flux rope insertion method. The MHD simulations confirm that the stable model relaxes to a stable equilibrium, while the unstable model erupts as a CME. Comparisons between observations and MHD simulations of the CME are also presented.

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Nonlinear force-free modeling of magnetic fields in flare-productive active regions

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316000387 ◽

2015 ◽

Vol 11 (S320) ◽

pp. 167-174

Author(s):

M. S. Wheatland ◽

S. A. Gilchrist

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Boundary Data ◽

Numerical Solutions ◽

Free Field ◽

Active Regions ◽

Coronal Magnetic Field ◽

Nonlinear Force ◽

The Magnetic Field ◽

Force Free Field

AbstractWe review nonlinear force-free field (NLFFF) modeling of magnetic fields in active regions. The NLFFF model (in which the electric current density is parallel to the magnetic field) is often adopted to describe the coronal magnetic field, and numerical solutions to the model are constructed based on photospheric vector magnetogram boundary data. Comparative tests of NLFFF codes on sets of boundary data have revealed significant problems, in particular associated with the inconsistency of the model and the data. Nevertheless NLFFF modeling is often applied, in particular to flare-productive active regions. We examine the results, and discuss their reliability.

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Studying Magnetic Field Variations Accompanying the 2011 June 7 Eruptive Event, by Using Nonlinear Force-Free Field Modeling

Solar Physics ◽

10.1007/s11207-020-01613-3 ◽

2020 ◽

Vol 295 (4) ◽

Author(s):

Y. I. Egorov ◽

V. G. Fainshtein ◽

I. I. Myshyakov ◽

S. A. Anfinogentov ◽

G. V. Rudenko

Keyword(s):

Magnetic Field ◽

Free Field ◽

Eruptive Event ◽

Field Modeling ◽

Nonlinear Force ◽

Magnetic Field Variations ◽

Force Free Field

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Nonlinear force-free field extrapolation of the coronal magnetic field using the data obtained by the Hinode satellite

Journal of Geophysical Research Atmospheres ◽

10.1029/2010ja015610 ◽

2011 ◽

Vol 116 (A1) ◽

pp. n/a-n/a ◽

Cited By ~ 15

Author(s):

Han He ◽

Huaning Wang ◽

Yihua Yan

Keyword(s):

Magnetic Field ◽

Free Field ◽

Coronal Magnetic Field ◽

Nonlinear Force ◽

Force Free Field

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Magnetic field topology from non-force free extrapolation and magnetohydrodynamic simulation of its eventual dynamics

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318001163 ◽

2018 ◽

Vol 13 (S340) ◽

pp. 183-184

Author(s):

Sushree S. Nayak ◽

R. Bhattacharyya ◽

A. Prasad ◽

Q. Hu

Keyword(s):

Magnetic Field ◽

Lorentz Force ◽

Free Field ◽

Magnetic Field Topology ◽

Mhd Simulations ◽

Extrapolation Scheme ◽

Magnetohydrodynamic Simulation ◽

Force Free Field ◽

Contemporary Standard

AbstractMagnetic reconnections (MRs) for various magnetic field line (MFL) topologies are believed to be the initiators of solar eruptive events like flares and coronal mass ejections (CMEs). Consequently, important is a thorough understanding and quantification of the MFL topology and their evolution which leads to MRs. Contemporary standard is to extrapolate the coronal MFLs using equilibrium models where the Lorentz force on the coronal plasma is zero everywhere. In tandem, a non-force-free-field (NFFF) extrapolation scheme has evolved and allows for a Lorentz force which is non-zero only at the photosphere but asymptotically vanishes with height. The paper reports magnetohydrodynamic (MHD)- simulations initiated by NFFF extrapolation of the coronal MFLs for a flare producing active region NOAA 11158. Interestingly, quasi-separatrix layers (QSLs) which facilitate MRs are detected in the extrapolated MFLs and, here the paper makes an attempt to asses the role of QSLs in the flare onsets.

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Magnetohydrodynamic study on the effect of the gravity stratification on flux rope ejections

Proceedings of the International Astronomical Union ◽

10.1017/s174392131301096x ◽

2013 ◽

Vol 8 (S300) ◽

pp. 197-200

Author(s):

Paolo Pagano ◽

Duncan H. Mackay ◽

Stefaan Poedts

Keyword(s):

Free Field ◽

Flux Rope ◽

Decisive Role ◽

Propagation Speed ◽

The Sun ◽

Magnetic Structures ◽

Mhd Simulations ◽

Linear Force ◽

Force Free Field ◽

Solar Gravity

AbstractCoronal Mass Ejections (CMEs) are one of the most violent phenomena found on the Sun. One model to explain their occurrence is the flux rope ejection model where these magnetic structures firt form in the solar corona then are ejected to produce a CME. We run simulations coupling two models. The Global Non-Linear Force-Free Field (GNLFFF) evolution model to follow the quasi-static formation of a flux rope and MHD simulations for the production of a CME through the loss of equilibrium and ejection of this flux rope in presence of solar gravity and density stratification. Our realistic multi-beta simulations describe the CME following the flux rope ejection and highlight the decisive role played by the gravity stratification on the CME propagation speed.

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Simulating the Coronal Evolution of Bipolar Active Regions to Investigate the Formation of Flux Ropes

Solar Physics ◽

10.1007/s11207-020-01749-2 ◽

2021 ◽

Vol 296 (1) ◽

Author(s):

S. L. Yardley ◽

D. H. Mackay ◽

L. M. Green

Keyword(s):

Magnetic Field ◽

Large Scale ◽

Initial Conditions ◽

Free Field ◽

Active Regions ◽

Coronal Magnetic Field ◽

Solar Dynamics Observatory ◽

Horizontal Magnetic Field ◽

Nonlinear Force ◽

Force Free Field

AbstractThe coronal magnetic field evolution of 20 bipolar active regions (ARs) is simulated from their emergence to decay using the time-dependent nonlinear force-free field method of Mackay, Green, and van Ballegooijen (Astrophys. J. 729, 97, 2011). A time sequence of cleaned photospheric line-of-sight magnetograms, which covers the entire evolution of each AR, is used to drive the simulation. A comparison of the simulated coronal magnetic field with the 171 and 193 Å observations obtained by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA), is made for each AR by manual inspection. The results show that it is possible to reproduce the evolution of the main coronal features such as small- and large-scale coronal loops, filaments and sheared structures for 80% of the ARs. Varying the boundary and initial conditions, along with the addition of physical effects such as Ohmic diffusion, hyperdiffusion and a horizontal magnetic field injection at the photosphere, improves the match between the observations and simulated coronal evolution by 20%. The simulations were able to reproduce the build-up to eruption for 50% of the observed eruptions associated with the ARs. The mean unsigned time difference between the eruptions occurring in the observations compared to the time of eruption onset in the simulations was found to be ≈5 hrs. The simulations were particularly successful in capturing the build-up to eruption for all four eruptions that originated from the internal polarity inversion line of the ARs. The technique was less successful in reproducing the onset of eruptions that originated from the periphery of ARs and large-scale coronal structures. For these cases global, rather than local, nonlinear force-free field models must be used. While the technique has shown some success, eruptions that occur in quick succession are difficult to reproduce by this method and future iterations of the model need to address this.

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Chromospheric Magnetic Field: A Comparison of He i 10830 Å Observations with Nonlinear Force-free Field Extrapolation

The Astrophysical Journal ◽

10.3847/1538-4357/ab9816 ◽

2020 ◽

Vol 898 (1) ◽

pp. 32 ◽

Cited By ~ 1

Author(s):

Yusuke Kawabata ◽

Andrés Asensio Ramos ◽

Satoshi Inoue ◽

Toshifumi Shimizu

Keyword(s):

Magnetic Field ◽

Free Field ◽

Nonlinear Force ◽

Force Free Field

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Tests and applications of nonlinear force-free field extrapolations in spherical geometry

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313003190 ◽

2012 ◽

Vol 8 (S294) ◽

pp. 553-554

Author(s):

Y. Guo ◽

M. D. Ding

Keyword(s):

Magnetic Field ◽

Analytical Solution ◽

Large Scale ◽

Initial Conditions ◽

Free Field ◽

Spherical Geometry ◽

Source Surface ◽

Field Source ◽

Nonlinear Force ◽

Force Free Field

AbstractWe test a nonlinear force-free field (NLFFF) optimization code in spherical geometry with an analytical solution from Low and Lou. The potential field source surface (PFSS) model is served as the initial and boundary conditions where observed data are not available. The analytical solution can be well recovered if the boundary and initial conditions are properly handled. Next, we discuss the preprocessing procedure for the noisy bottom boundary data, and find that preprocessing is necessary for NLFFF extrapolations when we use the observed photospheric magnetic field as bottom boundaries. Finally, we apply the NLFFF model to a solar area where four active regions interacting with each other. An M8.7 flare occurred in one active region. NLFFF modeling in spherical geometry simultaneously constructs the small and large scale magnetic field configurations better than the PFSS model does.

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