Regularized Biot–Savart Laws for Modeling Magnetic Flux Ropes

Titov, V. S.; Downs, Cooper; Mikić, Z.; Török, Tibor; Linker, J. A.; Caplan, Ronald M.

doi:10.3847/2041-8213/aaa3da

Cited by 49 publications

(80 citation statements)

References 32 publications

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“…We have very recently developed a new model, which allows one to construct analytical flux-rope configurations with an arbitrary axis shape(Titov et al 2018). This model would have strongly facilitated the construction of the complex pre-eruptive configuration, but it was not yet available when we performed the simulation described here.…”

mentioning

confidence: 99%

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Török¹,

Downs²,

Linker³

et al. 2018

ApJ

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159

114

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Solar eruptions are the main driver of space-weather disturbances at the Earth. Extreme events are of particular interest, not only because of the scientific challenges they pose, but also because of their possible societal consequences. Here we present a magnetohydrodynamic (MHD) simulation of the 14 July 2000 "Bastille Day" eruption, which produced a very strong geomagnetic storm. After constructing a "thermodynamic" MHD model of the corona and solar wind, we insert a magnetically stable flux rope along the polarity inversion line of the eruption's source region and initiate the eruption by boundary flows. More than 10 33 ergs of magnetic energy are released in the eruption within a few minutes, driving a flare, an EUV wave, and a coronal mass ejection (CME) that travels in the outer corona at ≈ 1500 km s −1 , close to the observed speed. We then propagate the CME to Earth, using a heliospheric MHD code. Our simulation thus provides the opportunity to test how well in situ observations of extreme events are matched if the eruption is initiated from a stable magnetic-equilibrium state. We find that the flux-rope center is very similar in character to the observed magnetic cloud, but arrives ≈ 8.5 hours later and ≈ 15 • too far to the North, with field strengths that are too weak by a factor of ≈ 1.6. The front of the flux rope is highly distorted, exhibiting localized magnetic-field concentrations as it passes 1 AU. We discuss these properties with regard to the development of space-weather predictions based on MHD simulations of solar eruptions.

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mentioning

confidence: 99%

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Török¹,

Downs²,

Linker³

et al. 2018

ApJ

Self Cite

159

114

View full text Add to dashboard Cite

show abstract

“…The Data-Optimized Coronal Field Model 3 (DOCFM; Dalmasse et al 2019) proposes such a solution by combining a parametrized FFF model with forward modeling of the coronal polarization signal in the Fe XIII lines. In this framework, the FFF model is parametrized through its electric currents 4 , which can either be a surface-boundary parametrization for FFF extrapolation methods, or a volume parametrization of the coronal electric currents for flux rope insertion methods (e.g., van Ballegooijen 2004;Titov et al 2014Titov et al , 2018. The parametrized FFF model is then optimized by minimizing the mean squared error between the polarization signal predicted for the FFF model and the real polarization signal (e.g.…”

Section: Combining Surface Magnetograms With Off-limb Coronal Polarimmentioning

confidence: 99%

Models and data analysis tools for the Solar Orbiter mission

Rouillard

Pinto

Vourlidas

et al. 2020

A&A

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Context. The Solar Orbiter spacecraft will be equipped with a wide range of remote-sensing (RS) and in-situ (IS) instruments to record novel and unprecedented measurements of the solar atmosphere and the inner heliosphere. To take full advantage of these new datasets, tools and techniques must be developed to ease multi-instrument and multi-spacecraft studies. In particular the currently inaccessible low solar corona below two solar radii can only be observed remotely. Furthermore techniques must be used to retrieve coronal plasma properties in time and in three dimensional (3D) space. Solar Orbiter will run complex observation campaigns that provide interesting opportunities to maximise the likelihood of linking IS data to their source region near the Sun. Several RS instruments can be directed to specific targets situated on the solar disk just days before data acquisition. To compare IS and RS, data we must improve our understanding of how heliospheric probes magnetically connect to the solar disk. Aims. The aim of the present paper is to briefly review how the current modelling of the Sun and its atmosphere can support Solar Orbiter science. We describe the results of a community-led effort by European Space Agency (ESA)'s Modelling and Data Analysis Working Group (MADAWG) to develop different models, tools, and techniques deemed necessary to test different theories for the physical processes that may occur in the solar plasma. The focus here is on the large scales and little is described with regards to kinetic processes. To exploit future IS and RS data fully, many techniques have been adapted to model the evolving 3D solar magneto-plasma from the solar interior to the solar wind. A particular focus in the paper is placed on techniques that can estimate how Solar Orbiter will connect magnetically through the complex coronal magnetic fields to various photospheric and coronal features in support of spacecraft operations and future scientific studies. Methods. Recent missions such as STEREO, provided great opportunities for RS, IS, and multi-spacecraft studies. We summarise the achievements and highlight the challenges faced during these investigations, many of which motivated the Solar Orbiter mission. We present the new tools and techniques developed by the MADAWG to support the science operations and the analysis of the data from the many instruments on Solar Orbiter. Results. This article reviews current modelling and tool developments that ease the comparison of model results with RS and IS data made available by current and upcoming missions. It also describes the modelling strategy to support the science operations and subsequent exploitation of Solar Orbiter data in order to maximise the scientific output of the mission. Conclusions. The on-going community effort presented in this paper has provided new models and tools necessary to support mission operations as well as the science exploitation of the Solar Orbiter data. The tools and techniques will no doubt evolve significantly as we refine our proc...

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“…A generative 3D magnetic field model (i.e., extrapolation/reconstruction) parametrized through its electric currents. This can be done either at the photospheric boundary (e.g., by means of the transverse magnetic field or the force-free parameter) or in the volume (e.g., for flux rope insertion methods; e.g., van Ballegooijen 2004;Titov et al 2014Titov et al , 2018). The generative model then creates the physical state of the corona (e.g., magnetic field, plasma pressure, density, temperature).…”

Section: Summary Of Approachmentioning

confidence: 99%

Data-optimized Coronal Field Model. I. Proof of Concept

Dalmasse

Savcheva

Gibson

et al. 2019

ApJ

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Deriving the strength and direction of the three-dimensional (3D) magnetic field in the solar atmosphere is fundamental for understanding its dynamics. Volume information on the magnetic field mostly relies on coupling 3D reconstruction methods with photospheric and/or chromospheric surface vector magnetic fields. Infrared coronal polarimetry could provide additional information to better constrain magnetic field reconstructions. However, combining such data with reconstruction methods is challenging, e.g., because of the opticalthinness of the solar corona and the lack and limitations of stereoscopic polarimetry. To address these issues, we introduce the Data-Optimized Coronal Field Model (DOCFM) framework, a model-data fitting approach that combines a parametrized 3D generative model, e.g., a magnetic field extrapolation or a magnetohydrodynamic model, with forward modeling of coronal data. We test it with a parametrized flux rope insertion method and infrared coronal polarimetry where synthetic observations are created from a known "ground truth" physical state. We show that this framework allows us to accurately retrieve the ground truth 3D magnetic field of a set of force-free field solutions from the flux rope insertion method. In observational studies, the DOCFM will provide a means to force the solutions derived with different reconstruction methods to satisfy additional, common, coronal constraints. The DOCFM framework therefore opens new perspectives for the exploitation of coronal polarimetry in magnetic field reconstructions and for developing new techniques to more reliably infer the 3D magnetic fields that trigger solar flares and coronal mass ejections.

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Regularized Biot–Savart Laws for Modeling Magnetic Flux Ropes

Cited by 49 publications

References 32 publications

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Sun-to-Earth MHD Simulation of the 2000 July 14 “Bastille Day” Eruption

Models and data analysis tools for the Solar Orbiter mission

Data-optimized Coronal Field Model. I. Proof of Concept

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