A Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections in NOAA AR 12192, Initiated with an Extrapolated Non-force-free Field

Prasad, A.; Bhattacharyya, R.; Hu, Qiang; Kumar, Sanjay; Nayak, Sushree S.

doi:10.3847/1538-4357/aac265

Cited by 33 publications

(33 citation statements)

References 70 publications

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“…The dynamics of the MFLs leading to the flare require full MHD simulations with these NFFF as initial fields. This has been presented in Prasad et al (2018).…”

Section: Resultsmentioning

confidence: 99%

Study of magnetic field topology of active region 12192 using an extrapolated non-force-free magnetic field

Prasad

Bhattacharyya

et al. 2018

Proc. IAU

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The solar active region (AR) 12192 was one of the most flare productive region of solar cycle 24, which produced many X-class flares; the most energetic being an X3.1 flare on October 24, 2014 at 21:10 UT. Customarily, such events are believed to be triggered by magnetic reconnection in coronal magnetic fields. Here we use the vector magnetograms from solar photosphere, obtained from Heliospheric Magnetic Imager (HMI) to investigate the magnetic field topology prior to the X3.1 event, and ascertain the conditions that might have caused the flare. To infer the coronal magnetic field, a novel non-force-free field (NFFF) extrapolation technique of the photospheric field is used, which suitably mimics the Lorentz forces present in the photospheric plasma. We also highlight the presence of magnetic null points and quasi-separatrix layers (QSLs) in the magnetic field topology, which are preferred sites for magnetic reconnections and discuss the probable reconnection scenarios.

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“…The dynamics of the MFLs leading to the flare require full MHD simulations with these NFFF as initial fields. This has been presented in Prasad et al (2018).…”

Section: Resultsmentioning

confidence: 99%

Study of magnetic field topology of active region 12192 using an extrapolated non-force-free magnetic field

Prasad

Bhattacharyya

et al. 2018

Proc. IAU

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“…These MRs being intermittent and local, successfully mimic physical MRs. The ILES property of MPDATA have proven instrumental in a series of advanced numerical studies across a range of scales and physical scenarios, including studies related to the coronal heating along with data-constrained simulations of solar flares and coronal jets (Bhattacharyya et al 2010;Kumar & Bhattacharyya 2011; 6 bora et al Kumar et al 2015Kumar et al , 2017Prasad et al 2017Prasad et al , 2018Nayak et al 2019Nayak et al , 2020. The simulations reported in this paper also benefit from ILES property of MPDATA.…”

Section: The Numerical Modelmentioning

confidence: 97%

Evolution of three-dimensional coherent structures in Hall magnetohydrodynamics

Bora,

Bhattacharyya,

Smolarkiewicz

2020

Preprint

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The work extends the computational model EULAG-MHD to include Hall magnetohydrodynamics (HMHD)-important to explore physical systems undergoing fast magnetic reconnection at the order of the ion inertial length scale. Examples include solar transients along with reconnections in magnetosphere, magnetotail and laboratory plasmas. The paper documents the results of two distinct sets of implicit large-eddy simulations in the presence and absence of the Hall forcing term, initiated with an unidirectional sinusoidal magnetic field. The HMHD simulation while benchmarking the code also emphasizes the complexity of three dimensional (3D) evolution over its two dimensional (2D) counterpart. The magnetic reconnections onset significantly earlier in HMHD. Importantly, the magnetic field generated by the Hall term breaks any inherent symmetry, ultimately making the evolution 3D. The resulting 3D reconnections develop magnetic flux ropes and magnetic flux tubes. Projected on the reconnection plane, the ropes and tubes appear as magnetic islands, which later break into secondary islands, and finally coalesce to generate an X-type neutral point. These findings are in agreement with the theory and contemporary simulations of HMHD, and thus verify our extension of the EULAG-MHD model. The second set explores the influence of the Hall forcing on generation and ascend of a magnetic flux rope from sheared magnetic

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“…Subsequently, an optimal pair α = {α 1 , α 3 } is obtained by an iterative method which finds the pair that minimizes the average deviation between the observed (B t ) and the calculated (b t ) transverse field on the photospheric boundary. This is estimated by the following metric (Prasad et al 2018):…”

Section: Non-force-free Extrapolation Of Magnetic Fieldmentioning

confidence: 99%

“…However, missing from the simulations were the small-scale magnetic features and their influence on the MFL dynamics-which cannot be captured by analytical/semi-analytical models. A numerical NFFF extrapolation model developed by ; ; Gary (2009); Hu et al (2010) was used to initialize the MHD evolution of NOAA AR 12192 using the HMI vector magnetogram taken approximately 30 minutes prior to a confined X3.1 flare (Prasad et al 2018). Another NFFF initiated simulation, for the case of a blowout jet event was recently studied in Nayak et al (2019).…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections and Coronal dimmings during the X2.1 flare in NOAA AR 11283

Prasad,

Dissauer,

et al. 2020

Preprint

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The magnetohydrodynamics of active region NOAA 11283 is simulated using an initial non-force-free magnetic field extrapolated from its photospheric vector magnetogram. We focus on the magnetic reconnections at a magnetic null point that participated in the X2.1 flare on 2011 September 6 around 22:21 UT (SOL2011-09-06T22:21X2.1) followed by the appearance of circular flare ribbons and coronal dimmings. The initial magnetic field from extrapolation displays a three-dimensional (3D) null topology overlying a sheared arcade. Prior to the flare, magnetic loops rise due to the initial Lorentz force, and reconnect at the 3D null, leading to expansion and loss of confined plasma that produce the observed pre-flare coronal dimmings. Further, the simulated dynamics documents the transfer of twist from the arcade to the overlying loops through reconnections, developing a flux rope. The non-parallel field lines comprising the rope and lower-lying arcades form an X-type geometry. Importantly, the simultaneous reconnections at the 3D null and the X-type geometry can explain the observed circular and parallel flare ribbons. Reconnections at the 3D null transform closed inner spine field lines into open field lines of the outer spine. The footpoints of these open field lines correspond to a ring-shaped coronal dimming region, tracing the dome. Further, the flux rope bifurcates because of these reconnections which also results in the generation of open magnetic field lines. The plasma loss along the open field lines can potentially explain the observed coronal dimming.

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A Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections in NOAA AR 12192, Initiated with an Extrapolated Non-force-free Field

Cited by 33 publications

References 70 publications

Study of magnetic field topology of active region 12192 using an extrapolated non-force-free magnetic field

Study of magnetic field topology of active region 12192 using an extrapolated non-force-free magnetic field

Evolution of three-dimensional coherent structures in Hall magnetohydrodynamics

Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections and Coronal dimmings during the X2.1 flare in NOAA AR 11283

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