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The response of the solar coronal magnetic field to small-scale photospheric boundary motions including the possible formation of current sheets via the Parker scenario is one of open questions of solar physics. Here we address the problem…

Solar and Stellar Astrophysics · Physics 2015-05-14 A. L. Wilmot-Smith , D. I. Pontin , G. Hornig

We present a new computational method for smoothly matching general relativistic ideal magnetohydrodynamics (MHD) to its force-free limit. The method is based on a flux-conservative formalism for MHD and its force-free limit, and a vector…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Vasileios Paschalidis , Stuart L. Shapiro

We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general…

Astrophysics · Physics 2009-11-13 M. K. Georgoulis , Barry J. LaBonte

Extrapolation codes for modelling the magnetic field in the corona in cartesian geometry do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, \textit{e.g.}, a single active region.…

Solar and Stellar Astrophysics · Physics 2011-04-13 T. Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

An interpolation method to evaluate magnetic fields given unstructured, scattered magnetic data is presented. The method is based on the reconstruction of the global magnetic field using a superposition of orthogonal functions. The…

Computational Physics · Physics 2023-03-15 Minglei Yang , Diego del-Castillo-Negrete , Guannan Zhang , Matthew Beidler

We derive a new 3D model for magnetic particle imaging (MPI) that is able to incorporate realistic magnetic fields in the reconstruction process. In real MPI scanners, the generated magnetic fields have distortions that lead to deformed…

Numerical Analysis · Mathematics 2020-12-30 Gaël Bringout , Wolfgang Erb , Jürgen Frikel

We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Philip G. Judge , Shadia Habbal , Enrico Landi

Cardiac cine magnetic resonance imaging (MRI) can be considered the optimal criterion for measuring cardiac function. This imaging technique can provide us with detailed information about cardiac structure, tissue composition and even blood…

Image and Video Processing · Electrical Eng. & Systems 2022-05-25 Nourelhouda Groun , Maria Villalba-Orero , Enrique Lara-Pezzi , Eusebio Valero , Jesus Garicano-Mena , Soledad Le Clainche

Magnetic field extrapolation from the solar photosphere to the corona plays an important role in solar physics research. In this work, we present a fully-implicit viscous-relaxation nonlinear force-free field (FIVR-NLFFF) extrapolation code…

Solar and Stellar Astrophysics · Physics 2025-09-18 Zhenhua Liu , Chaowei Jiang

We propose a new method to compute magnetic surfaces that are parametrized in Boozer coordinates for vacuum magnetic fields. We also propose a measure for quasi-symmetry on the computed surfaces and use it to design coils that generate a…

Plasma Physics · Physics 2022-08-17 Andrew Giuliani , Florian Wechsung , Matt Landreman , Georg Stadler , Antoine Cerfon

The shapes of solar coronal loops are sensitive to the presence of electrical currents that are the carriers of the nonpotential energy available for impulsive activity. We use this information in a new method for modeling the coronal…

Solar and Stellar Astrophysics · Physics 2021-06-29 A. Malanushenko , C. Schrijver , M. L. DeRosa , M. S. Wheatland

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

A nonlinear force-free solution is constructed for the coronal magnetic field in NOAA solar active region AR 10953 based on a photospheric vector magnetogram derived from Hinode satellite observations on 30 April 2007, taking into account…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. S. Wheatland , K. D. Leka

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

Magnetic Resonance Imaging (MRI) is a noninvasive imaging technique that provides exquisite soft-tissue contrast without using ionizing radiation. The clinical application of MRI may be limited by long data acquisition times; therefore, MR…

Image and Video Processing · Electrical Eng. & Systems 2020-07-10 Shen Zhao , Lee C. Potter , Kiryung Lee , Rizwan Ahmad

We construct maximally recoverable codes (corresponding to partial MDS codes) which are based on linearized Reed-Solomon codes. The new codes have a smaller field size requirement compared with known constructions. For certain asymptotic…

Information Theory · Computer Science 2021-10-15 Han Cai , Ying Miao , Moshe Schwartz , Xiaohu Tang

This work introduces a systematic method for identifying analytical and semi-analytical solutions of force-free magnetic fields with plane-parallel and axial symmetry. The method of separation of variables is used, allowing the…

High Energy Astrophysical Phenomena · Physics 2025-01-28 Konstantinos N. Gourgouliatos

Observations of surface magnetic fields are now within reach for many stellar types thanks to the development of Zeeman-Doppler Imaging. These observations are extremely useful for constraining rotational evolution models of stars, as well…

Solar and Stellar Astrophysics · Physics 2015-09-24 Victor Réville , Allan Sacha Brun , Antoine Strugarek , Sean P. Matt , Jérôme Bouvier , Colin P. Folsom , Pascal Petit

In this review, I focus on the structure and evolution of the coronal magnetic fields modelled from observations. The development of instruments measuring the photospheric and chromospheric magnetic fields with a high spatial and time…

Solar and Stellar Astrophysics · Physics 2011-01-18 Stephane Regnier

The reduction of magnetic forces on electromagnetic coils is an important consideration in the design of high-field devices such as the stellarator or tokamak. Unfortunately, these forces may be too time-consuming to evaluate by…

Plasma Physics · Physics 2024-10-15 Siena Hurwitz , Matt Landreman , Alan Kaptanoglu