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In this work, the Flux-Coordinate Independent (FCI) approach to plasma turbulence simulations is formulated for the case of generic, static magnetic fields, including those possessing stochastic field lines. It is then demonstrated that FCI…

Plasma Physics · Physics 2015-04-28 F. Hariri , P. Hill , M. Ottaviani , Y. Sarazin

Advanced divertor configurations modify the magnetic geometry of the diverter to achieve a combination of strong magnetic flux expansion, increased connection length and higher divertor volume - to improve detachment stability,…

Plasma Physics · Physics 2020-08-26 Thomas Body , Andreas Stegmeir , Wladimir Zholobenko , David Coster , Frank Jenko

We present a technique for handling Dirichlet boundary conditions with the Flux Coordinate Independent (FCI) parallel derivative operator with arbitrary-shaped material geometry in general 3D magnetic fields. The FCI method constructs a…

Plasma Physics · Physics 2017-03-08 Peter Hill , Brendan Shanahan , Ben Dudson

This paper proposes a geomagnetic and inertial combined navigation approach based on the flexible correction-model predictive control algorithm (Fc-MPC). This approach aims to overcome the limitations of existing combined navigation methods…

Systems and Control · Electrical Eng. & Systems 2024-12-10 Xiaohui Zhang , Xingming Li , Songnan Yang , Wenqi Bai , Yirong Lan

This study presents a finite difference method (FDM) to model the electromagnetic field propagation in eccentric coaxial waveguides filled with lossy uniaxially anisotropic media. The formulation utilizes conformal transformation to map the…

Computational Engineering, Finance, and Science · Computer Science 2025-01-24 Raul O. Ribeiro , Maria A. Martinez , Guilherme S. Rosa , Rafael A. Penchel

Fluid simulation of stellarator edge transport is difficult due to the complexities of mesh generation; the stochastic edge and strong nonaxisymmetry inhibit the use of field aligned coordinate systems. The recent implementation of the Flux…

Plasma Physics · Physics 2016-12-21 Brendan Shanahan , Peter Hill , Ben Dudson

A hybrid spectral/finite-element code is developed to numerically solve the resistive finite-pressure magnetohydrodynamic equilibria without the necessity of postulating nested magnetic flux surfaces in the non-axisymmetric toroidal…

Plasma Physics · Physics 2024-12-30 Jian Zhang , Ping Zhu , Chris C. Hegna

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

We present a collection of well-conditioned integral equation methods for the solution of electrostatic, acoustic or electromagnetic scattering problems involving anisotropic, inhomogeneous media. In the electromagnetic case, our approach…

Numerical Analysis · Mathematics 2018-05-15 Lise-Marie Imbert-Gerard , Felipe Vico , Leslie Greengard , Miguel Ferrando

A new numerical scheme to solve the Einstein field equations based upon the generalized harmonic decomposition of the Ricci tensor is introduced. The source functions driving the wave equations that define generalized harmonic coordinates…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Frans Pretorius

In this work, we develop a novel fault detection and isolation (FDI) scheme for discrete-time two-dimensional (2D) systems that are represented by the Fornasini-Marchesini model II (FMII). This is accomplished by generalizing the basic…

Systems and Control · Computer Science 2016-09-20 Amir Baniamerian , Nader Meskin , Khashayar Khorasani

We present a new technique for the numerical simulation of axisymmetric systems. This technique avoids the coordinate singularities which often arise when cylindrical or polar-spherical coordinate finite difference grids are used,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. Alcubierre , S. Brandt , B. Bruegmann , D. Holz , E. Seidel , R. Takahashi , J. Thornburg

We propose a numerical method for the solution of electromagnetic problems on axisymmetric domains, based on a combination of a spectral Fourier approximation in the azimuthal direction with an IsoGeometric Analysis (IGA) approach in the…

Numerical Analysis · Mathematics 2020-07-15 Abele Simona , Luca Bonaventura , Carlo de Falco , Sebastian Schöps

We develop an efficient algorithm, coordinate descent FCI (CDFCI), for the electronic structure ground state calculation in the configuration interaction framework. CDFCI solves an unconstrained non-convex optimization problem, which is a…

Chemical Physics · Physics 2019-07-03 Zhe Wang , Yingzhou Li , Jianfeng Lu

The magnetic field outside the earth is in good approximation a harmonic vector field determined by its values at the earth's surface. The direction problem seeks to determine harmonic vector fields vanishing at infinity and with prescribed…

Analysis of PDEs · Mathematics 2019-09-26 Ralf Kaiser , Tobias Ramming

We present an exact solution to the problem of a self-consistent equilibrium force-free magnetic flux rope. Unlike other approaches, we use magnetostatic equations and assume only a relatively rapid decrease in the axial magnetic field at…

Pattern Formation and Solitons · Physics 2024-08-19 O. K. Cheremnykh , V. M. Lashkin

We present a novel randomized block coordinate descent method for the minimization of a convex composite objective function. The method uses (approximate) partial second-order (curvature) information, so that the algorithm performance is…

Optimization and Control · Mathematics 2018-02-28 Kimon Fountoulakis , Rachael Tappenden

We consider the method of mappings for performing shape optimization for unsteady fluid-structure interaction (FSI) problems. In this work, we focus on the numerical implementation. We model the optimization problem such that it takes…

Optimization and Control · Mathematics 2024-06-21 Johannes Haubner , Michael Ulbrich

It is shown that conformal symmetry exists in force-free electrodynamics (FFE) in Minkowski spacetime, a foundational framework for describing magnetospheres around astronomical objects. In force-free magnetospheres, charges are constrained…

General Relativity and Quantum Cosmology · Physics 2026-03-27 Huiquan Li , Jianyong Wang

This paper deals with the modelling of superconducting and resistive wires with a helicoidal symmetry, subjected to an external field and a transport current. Helicoidal structures are three-dimensional, and therefore yield computationally…

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