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Related papers: A Nonlinear Force-Free Magnetic Field Approximatio…

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In earlier works we introduced and tested a nonlinear force-free (NLFF) method designed to self-consistently calculate the free magnetic energy and the relative magnetic helicity budgets of the corona of observed solar magnetic structures.…

Solar and Stellar Astrophysics · Physics 2015-06-22 K. Moraitis , K. Tziotziou , M. K. Georgoulis , V. Archontis

Function-correcting codes are a coding framework designed to minimize redundancy while ensuring that specific functions or computations of encoded data can be reliably recovered, even in the presence of errors. The choice of metric is…

Information Theory · Computer Science 2026-02-18 Gyanendra K. Verma , Abhay Kumar Singh

We present numerical models from the field-aligned Hydrodynamics and Radiation Code (HYDRAD) of a highly asymmetric closed coronal loop with near-singular expansion factor. This loop was chosen to simulate a coronal magnetic flux tube that…

Solar and Stellar Astrophysics · Physics 2023-02-08 Emily I Mason , Spiro K Antiochos , Stephen Bradshaw

Solar filament are commonly thought to be supported in magnetic dips, in particular, of magnetic flux ropes (FRs). In this Letter, from the observed photospheric vector magnetogram, we implement a nonlinear force-free field (NLFFF)…

Solar and Stellar Astrophysics · Physics 2015-06-19 Chaowei Jiang , S. T. Wu , Xueshang Feng , Qiang Hu

Numerical reconstruction/extrapolation of coronal nonlinear force-free magnetic field (NLFFF) usually takes the photospheric vector magnetogram as input at the bottom boundary. Magnetic field observed at the photosphere, however, contains…

Solar and Stellar Astrophysics · Physics 2015-06-16 Chaowei Jiang , Xueshang Feng

In recent years, a two-dimensional (2D) coronal seismology technique applied to spectral-imaging data from the Coronal Multi-channel Polarimeter (CoMP) and UCoMP has enabled routine measurement of the global coronal magnetic field. The…

Solar and Stellar Astrophysics · Physics 2026-01-16 Zihao Yang , Sarah Gibson , Matthias Rempel , Giuliana de Toma

Nonlinear force-free solutions for the magnetic field in the solar corona constructed using photospheric vector magnetic field boundary data suffer from a basic problem: the observed boundary data are inconsistent with the nonlinear…

Solar and Stellar Astrophysics · Physics 2009-07-22 M. S. Wheatland , S. Regnier

We present an efficient and very flexible numerical fast Fourier-Laplace transform, that extends the logarithmic Fourier transform (LFT) introduced by Haines and Jones [Geophys. J. Int. 92(1):171 (1988)] for functions varying over many…

Numerical Analysis · Mathematics 2019-11-05 Johannes Lang , Bernhard Frank

Knowledge regarding the coronal magnetic field is important for the understanding of many phenomena, like flares and coronal mass ejections. Because of the low plasma beta in the solar corona the coronal magnetic field is often assumed to…

Astrophysics · Physics 2008-11-26 Thomas Wiegelmann , Bernd Inhester , Takashi Sakurai

This paper presents novel methods to approximate the nonlinear AC optimal power flow (OPF) into tractable linear/quadratic programming (LP/QP) based OPF problems that can be used for power system planning and operation. We derive a linear…

Systems and Control · Computer Science 2019-03-19 Philipp Fortenbacher , Turhan Demiray

We present a new improved version of our force-free electrodynamics (FFE) numerical code in spherical coordinates that extrapolates the magnetic field in the inner solar corona from a photospheric vector magnetogram. The code satisfies the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Ioannis Contopoulos

We compare magnetic field extrapolations from a photospheric magnetogram with the observationally inferred structure of magnetic loops in a newly developed active region. This is the first time that the reconstructed 3D-topology of the…

Astrophysics · Physics 2009-06-25 T. Wiegelmann , A. Lagg , S. K. Solanki , B. Inhester , J. Woch

Active region EUV loops are believed to trace a subset of magnetic field lines through the corona. Malanushenko et al. (2009) proposed a method, using loop images and line-of-sight photospheric magnetograms, to infer the three-dimensional…

Solar and Stellar Astrophysics · Physics 2021-05-27 Marika I. McCarthy , Dana W. Longcope , Anna Malanushenko

Context: Relaxation theory offers a straightforward method for estimating the energy that is released when a magnetic field becomes unstable, as a result of continual convective driving. Aims: We present new results obtained from nonlinear…

Solar and Stellar Astrophysics · Physics 2015-06-12 Michael Bareford , Alan Hood , Philippa Browning

Coronal magnetic fields evolve quasi statically over long time scales and dynamically over short time scales. As of now there exists no regular measurements of coronal magnetic fields, and therefore generating the coronal magnetic field…

Solar and Stellar Astrophysics · Physics 2023-12-20 P. Vemareddy , Jörn Warnecke , Ph. A. Bourdin

We investigate in details properties of stationary force-free magnetosphere of aligned rotator assuming the last closed field line lying in equatorial plane at large distances from pulsar. The pulsar equations is solved numerically using…

Astrophysics · Physics 2009-11-11 A. N. Timokhin

In numerical simulations of cardiac mechanics, coupling the heart to a model of the circulatory system is essential for capturing physiological cardiac behavior. A popular and efficient technique is to use an electrical circuit analogy,…

For designing high-field electromagnets, the Lorentz force on coils must be computed to ensure a support structure is feasible, and the inductance should be computed to evaluate the stored energy. Also, the magnetic field and its variation…

Applied Physics · Physics 2023-10-19 Matt Landreman , Siena Hurwitz , Thomas M Antonsen

Non-linear force-free extrapolations are a common approach to estimate the 3D topology of coronal magnetic fields based on photospheric vector magnetograms. The force-free assumption is a valid approximation at coronal heights, but for the…

We present numerical studies of the nonlinear, resistive magnetohydrodynamic (MHD) evolution of coronal loops. For these simulations we assume that the loops carry no net current, as might be expected if the loop had evolved due to vortex…

Astrophysics · Physics 2009-10-31 T. D. Arber , A. W. Longbottom , R. A. M. Van der Linden