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AIMS: We develop an optimization principle for computing stationary MHD equilibria. METHODS: Our code for the self-consistent computation of the coronal magnetic fields and the coronal plasma uses non-force-free MHD equilibria. Previous…

Astrophysics · Physics 2008-11-26 Thomas Wiegelmann , Thomas Neukirch

This article is devoted to the shape optimization of the internal structure of an electric motor, and more precisely of the arrangement of air and ferromagnetic material inside the rotor part with the aim to increase the torque of the…

Optimization and Control · Mathematics 2024-02-13 Alessio Cesarano , Charles Dapogny , Peter Gangl

This paper presents an easy-to-control volume peeling method for multi-axis machining based on the computation taken on vector fields. The current scalar field based methods are not flexible and the vector-field based methods do not…

Computational Geometry · Computer Science 2023-10-05 Neelotpal Dutta , Tianyu Zhang , Guoxin Fang , Ismail E. Yigit , Charlie C. L. Wang

We consider systems of nonlinear magnetostatics and quasistatics that typically arise in the modeling and simulation of electric machines. The nonlinear problems, eventually obtained after time discretization, are usually solved by…

Numerical Analysis · Mathematics 2023-11-27 Herbert Egger , Felix Engertsberger , Bogdan Radu

Accelerated proximal gradient methods have recently been developed for solving quasi-static incremental problems of elastoplastic analysis with some different yield criteria. It has been demonstrated through numerical experiments that these…

Optimization and Control · Mathematics 2020-11-13 Yoshihiro Kanno

Context: The majority of studies on stressed 3D magnetic null points consider magnetic reconnection driven by an external perturbation, but the formation of a genuine current sheet equilibrium remains poorly understood. This problem has…

Solar and Stellar Astrophysics · Physics 2012-09-07 Jorge Fuentes-Fernandez , Clare E. Parnell

'Coil design' is an inverse problem in which arrangements of wire are designed to generate a prescribed magnetic field when energized with electric current. The design of gradient and shim coils for magnetic resonance imaging (MRI) are…

Classical Physics · Physics 2010-02-19 Michael Poole , Pierre Weiss , Hector Sanchez Lopez , Michael Ng , Stuart Crozier

We study the min-max optimization problem where each function contributing to the max operation is strongly-convex and smooth with bounded gradient in the search domain. By smoothing the max operator, we show the ability to achieve an…

Optimization and Control · Mathematics 2019-05-31 Hakan Gokcesu , Kaan Gokcesu , Suleyman Serdar Kozat

In stars and planets, magnetic fields are believed to originate from the motion of electrically conducting fluids in their interior, through a process known as the dynamo mechanism. In this Letter, an optimization procedure is used to…

Fluid Dynamics · Physics 2015-03-20 Ashley P. Willis

A Grad-Shafranov equation (GSE) valid for compact quasisymmetric stellarators is derived by an asymptotic expansion around a vacuum field carried to first order. We obtain an equation for the existence of flux surfaces leading up to the…

Plasma Physics · Physics 2025-03-25 Nikita Nikulsin , Wrick Sengupta , Stefan Buller , Amitava Bhattacharjee

We propose a new class of finite element approximations to ideal compressible magnetohydrodynamic equations in smooth regime. Following variational approximations developed for fluid models in the last decade, our discretizations are built…

Numerical Analysis · Mathematics 2024-02-29 Valentin Carlier , Martin Campos-Pinto

We propose an extremely versatile approach to address a large family of matrix nearness problems, possibly with additional linear constraints. Our method is based on splitting a matrix nearness problem into two nested optimization problems,…

Numerical Analysis · Mathematics 2025-08-14 Miryam Gnazzo , Vanni Noferini , Lauri Nyman , Federico Poloni

The mining in physics and biology for accelerating the hardcore algorithm to solve non-deterministic polynomial (NP) hard problems has inspired a great amount of special-purpose ma-chine models. Ising machine has become an efficient solver…

Emerging Technologies · Computer Science 2022-04-06 Wenchen Sun , Wenjia Zhang , Yuanyuan Liu , Qingwen Liu , Zuyuan He

It is demonstrated that finite-pressure, approximately quasi-axisymmetric stellarator equilibria can be directly constructed (without numerical optimization) via perturbations of given axisymmetric equilibria. The size of such perturbations…

Plasma Physics · Physics 2022-06-22 G. G. Plunk

Boundary conforming coordinates are commonly used in plasma physics to describe the geometry of toroidal domains, for example, in three-dimensional magnetohydrodynamic equilibrium solvers. The magnetohydrodynamic equilibrium configuration…

Plasma Physics · Physics 2025-02-07 Robert Babin , Florian Hindenlang , Omar Maj , Robert Köberl

In this work we describe a numerical optimization method for computing stationary MHD-equilibria. The newly developed code is based on a nonlinear force-free optimization principle. We apply our code to model the solar corona using synoptic…

Solar and Stellar Astrophysics · Physics 2020-11-11 Thomas Wiegelmann , Thomas Neukirch , Dieter H. Nickeler , Iulia Chifu

In shape optimisation it is desirable to obtain deformations of a given mesh without negative impact on the mesh quality. We propose a new algorithm using least square formulations of the Cauchy-Riemann equations. Our method allows to…

Optimization and Control · Mathematics 2021-06-09 José A. Iglesias , Kevin Sturm , Florian Wechsung

This paper details a methodology to transcribe an optimal control problem into a nonlinear program for generation of the trajectories that optimize a given functional by approximating only the highest order derivatives of a given system's…

Optimization and Control · Mathematics 2025-09-09 Thomas L. Ahrens , Ian M. Down , Manoranjan Majji

In this self-contained document, we aim to present the basic theoretical building blocks to understand modeling of stellarator magnetic fields, some of the challenges associated with modeling, and optimization for designing stellarators. As…

Plasma Physics · Physics 2020-08-11 Lise-Marie Imbert-Gerard , Elizabeth J. Paul , Adelle M. Wright

We consider a 2d permanent magnet synchronous machine operating in a sequence of static operating points coming from a drive cycle. We aim to find a rotor design which maximizes the efficiency defined as the quotient of input and output…

Optimization and Control · Mathematics 2026-04-01 Nepomuk Krenn , Théodore Cherrière , Sebastian Schöps , Peter Gangl