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Related papers: Tokamak to Stellarator Conversion using Permanent …

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Quasi-axisymmetric stellarators are the stellarator analogue of the axisymmetric tokamak, retaining many of its favorable confinement properties, its compacity and its relative coil simplicity, while avoiding its principal limitation, the…

Plasma Physics · Physics 2026-03-23 J. L. Velasco , I. Calvo , J. M. García-Regaña

A common optimization problem in the areas of magnetized plasmas and fusion energy is the design of magnets to produce a given three-dimensional magnetic field distribution to high precision. When designing arrays of permanent magnets for…

Plasma Physics · Physics 2024-02-20 K. C. Hammond , A. A. Kaptanoglu

Stellarator magnetic configurations need to be optimized in order to meet all the required properties of a fusion reactor. In this work, it is shown that a flat-mirror quasi-isodynamic configuration (i.e. a quasi-isodynamic configuration…

Plasma Physics · Physics 2023-11-08 J. L. Velasco , I. Calvo , E. Sánchez , F. I. Parra

We introduce a topology optimization method to design permanent magnets for advanced stellarators. Recent researches show that permanent magnets have great potentials to simplify stellarator coils. We adopt state-of-the-art numerical…

Nuclear fusion using magnetic confinement holds promise as a viable method for sustainable energy. However, most fusion devices have been experimental and as we move towards energy reactors, we are entering into a new paradigm of…

Plasma Physics · Physics 2023-10-04 Timothy Nunn , Vignesh Gopakumar , Sebastien Kahn

A long-term energy option that is just approaching the horizon after decades of struggle, is fusion. Recent developments allow us to apply techniques from spin physics to advance its viability. The cross section for the primary fusion fuel…

To better understand the dependence of the magnetic field structure in the plasma edge on the plasma boundary shape, in the context of X-point and island divertor designs, we define and develop a class of stellarators called umbilic…

Plasma Physics · Physics 2026-01-28 R. Gaur , D. Panici , T. M. Elder , M. Landreman , K. E. Unalmis , Y. Elmacioglu , D. Dudt , R. Conlin , E. Kolemen

A common scientific inverse problem is the placement of magnets that produce a desired magnetic field inside a prescribed volume. This is a key component of stellarator design, and recently permanent magnets have been proposed as a…

Plasma Physics · Physics 2022-10-05 Alan A. Kaptanoglu , Tony Qian , Florian Wechsung , Matt Landreman

The Tokamak device is the most promising candidate for producing sustainable electric power by nuclear fusion. It is a torus-shaped device that confines plasma by a strong magnetic field. The development, design and control of the design…

Plasma Physics · Physics 2022-11-17 M. Holst , V. Kungurtsev , S. Mukherjee

In piecewise omnigenous magnetic fields, charged particles remain perfectly confined in the abscence of collisions and turbulence. This concept extends the traditional notion of omnigenity, the theoretical principle upon which most of…

Designing magnets for three-dimensional plasma confinement is a key task for advancing the stellarator as a fusion reactor concept. Stellarator magnets must produce an accurate field while leaving adequate room for other components and…

Plasma Physics · Physics 2025-03-12 K. C. Hammond

Optimised stellarators and other magnetic-confinement devices having the property that the average magnetic curvature is favourable for all particle orbits are called maximum-$J$ devices, and have recently been shown to be immune to…

Plasma Physics · Physics 2017-08-15 G. G. Plunk , J. W. Connor , P. Helander

In preparation for extending the JOREK nonlinear MHD code to stellarators, a hierarchy of stellarator-capable reduced and full MHD models has been derived and tested. The derivation was presented at the EFTC 2019 conference. Continuing this…

Plasma Physics · Physics 2021-07-01 Nikita Nikulsin , Matthias Hoelzl , Alessandro Zocco , Karl Lackner , Sibylle Guenter

Design and modeling of a stellarator fusion reactor is a multidisciplinary effort that requires a tight integration between simulation of highly nonlinear multi-physics and representation of non-planar complex geometries. The critical…

Plasma Physics · Physics 2023-11-23 Merle Backmeyer , Nicolo Riva , Mika Lyly , Alexandre Halbach , Valtteri Lahtinen

Forty-five years ago a coordinate system was shown to exist that gave simple but exact expressions whenever and wherever a toroidal plasma equilibrium $\vec{\nabla}p=\vec{j}\times\vec{B}$ exists. These coordinates, now called Boozer…

Plasma Physics · Physics 2026-04-21 Allen H Boozer

Optimized stellarator configurations and their analytical properties are obtained using a near-axis expansion approach. Such configurations are associated with good confinement as the guiding center particle trajectories and neoclassical…

Plasma Physics · Physics 2020-08-26 R. Jorge , W. Sengupta , M. Landreman

We consider the novel problem of optimizing a large set of passive superconducting coils (PSCs) with currents induced by a background magnetic field rather than power supplies. In the nuclear fusion literature, such coils have been proposed…

Plasma Physics · Physics 2025-01-23 Alan A. Kaptanoglu , Matt Landreman , Michael C. Zarnstorff

Being three-dimensional, stellarators have the advantage that plasma currents are not essential for creating rotational-transform; however, the external current-carrying coils in stellarators can have strong geometrical shaping, which can…

Plasma Physics · Physics 2025-09-16 S. Guinchard , S. R. Hudson , E. J. Paul

This study investigates a simplified stellarator configuration employing circular coils, in which rotational transform is generated by tilting the toroidal field (TF) coils. A pair of axisymmetric poloidal field (PF) coils is introduced to…

Plasma Physics · Physics 2026-04-09 Ashit Kumar Nath , Yasuhiro Suzuki

Permanent magnets provide an attractive path for shaping university-scale stellarator magnetic fields. Previous work has shown that greedy permanent magnet optimization (GPMO) can produce sparse, grid-aligned arrays that match target…

Plasma Physics · Physics 2025-12-18 Armin Ulrich , Mason Haberle , Alan A. Kaptanoglu