Explanipedia

FOCUS-HTS: a new stellarator coil design code for three-dimensional high-temperature superconducting magnets Open

Xianyi Nie, Jinqing Peng, Yidong Xie, Guodong Yu, Ke Liu , et al. · 2025

Stellarators mainly utilize magnetic fields from external coils to confine the plasma, enabling steady-state operation while avoiding instabilities like disruptions raised from plasma currents. Similar to tokamaks, the fusion power of stel…

Host SUMOylation in bacterial infections and immune defense mechanisms Open

Yuhua Xu, Xi Ma, Zhifeng Wu, Ruitong Huang, Chenxi Liao , et al. · 2025

SUMOylation, the covalent attachment of small ubiquitin-like modifier proteins (SUMO) to lysine residues of target substrates, has emerged as a crucial post-translational modification regulating various cellular processes. Recent studies h…

Convergence and Stability of Discrete Exterior Calculus for the Hodge Laplace Problem in Two Dimensions Open

Caoxiang Zhu, Snorre H. Christiansen, Kaibo Hu, Anil N. Hirani · 2025

We prove convergence and stability of the discrete exterior calculus (DEC) solutions for the Hodge-Laplace problems in two dimensions for families of meshes that are non-degenerate Delaunay and shape regular. We do this by relating the DEC…

Sensitivity of magnetic islands in permanent magnet stellarators using the gradient and Hessian methods Open

Amelia Chambliss, Caoxiang Zhu, D. Gates, M. C. Zarnstorff, Tony Qian · 2025

Stellarator plasmas are known to be very sensitive to perturbations in the magnetic field. The permanent magnet stellarator was in part developed as a solution to high machining tolerances placed on the shape properties of electromagnetic …

Verification of the Shafranov shift in free-boundary VMEC, DESC, and SPEC calculations with elliptical geometry Open

S. R. Hudson, Dario Panici, Caoxiang Zhu, Gabriel S. Woodbury Saudeau, A. Baillod , et al. · 2025

Given a set of current-carrying filaments that create a magnetic field with rotating elliptical flux surfaces, we present verification calculations using the VMEC, DESC, and SPEC free-boundary magnetohydrostatic equilibrium codes for both …

Optimizing omnigenity like quasisymmetry for stellarators Open

Hai Liu, Guodong Yu, Caoxiang Zhu, Ge Zhuang · 2025

Omnigenous magnetic fields, where the bounce-averaged radial drift vanishes, offer a promising solution to confine charged particles in fusion devices, particularly in stellarators. However, nonquasisymmetric omnigenity has remained undere…

A new continuous optimization method of standardized cubic permanent magnets for stellarators Open

Xiangyu Zhang, Dehong Chen, Guosheng Xu, Zhiyuan Lu, Caoxiang Zhu , et al. · 2025

Stellarator configurations can be realized using permanent magnets in combination with tokamak-like planar coils. From the perspective of engineering feasibility and cost-effectiveness, using standardized cubic permanent magnets with a fin…

Design of 3D equilibria and coils for steady-state operation of tokamaks Open

Y. Liang, Yao Zhou, Fangling Dong, Caoxiang Zhu, Guodong Yu , et al. · 2024

Inspired by the respective advantages of tokamaks and stellarators, we propose a quasi-axisymmetric (QA) tokamak-stellarator hybrid concept as a steady-state operation mode of standard tokamaks. Using stellarator optimization tools, we obt…

Quasi-single-stage optimization for permanent magnet stellarators Open

Guodong Yu, Ke Liu, Tianyi Qian, Yidong Xie, Xianyi Nie , et al. · 2024

Advanced stellarators are typically optimized in two stages. The plasma equilibrium is optimized first, followed by the design of coils/permanent magnets. However, the coils/permanent magnets in the second stage may become too complex to a…

Effects of magnetic helicity on 3D equilibria and self-organized states in KTX reversed field pinch Open

Ke Liu, Guodong Yu, Yuhua Huang, Wenzhe Mao, Yidong Xie , et al. · 2024

The reversed field pinch (RFP) is a toroidal magnetic configuration in which plasmas can spontaneously transform into different self-organized states. Among various states, the ‘quasi-single-helical’ (QSH) state has a dominant component fo…

Quasi-single-stage optimization for permanent magnet stellarators Open

Guodong Yu, Ke Liu, Tianyi Qian, Yidong Xie, Xianyi Nie , et al. · 2024

Advanced stellarators are typically optimized in two stages. The plasma equilibrium is optimized first, followed by the design of coils/permanent magnets. However, the coils/permanent magnets in the second stage may become too complex to a…

Design and construction of the MUSE permanent magnet stellarator Open

Tony Qian, X. Chu, Christopher C. Pagano, D. Patch, M. C. Zarnstorff , et al. · 2023

This paper documents the design and construction of MUSE, the world's first permanent magnet (PM) stellarator and the first quasi-axisymmetric experiment. The purpose of MUSE is to develop and assess a new way of building optimised stellar…

FES 2023 Theory & Simulation Performance Target Open

S. R. Hudson, Adelle Wright, A. S. Ware, J.C. Schmitt, J.D. Hanson , et al. · 2023

The Report for the 2023 Theory & Simulation Performance Target (TSPT) is presented herein. The 1st, 2nd and 3rd Quarter Reports are given in Sec. I, Sec. II and Sec. III. These are unchanged from those previously submitted, except that in …

Stellarator Simplification using Permanent Magnets (PM4Stell) Open

K. Hammond, D. Gates, Robert Mercurio, D.A. Maurer, D Bishop , et al. · 2023

This Report describes the design and prototyping of an array of rare-Earth permanent magnets to form a stellarator. This effort was motivated by the hypothesis that the usage of permanent magnets, rather than electromagnetic coils with com…

Stellarator Simplification using Permanent Magnets (PM4Stell) Open

K. Hammond, D. Gates, Robert Mercurio, D.A. Maurer, D Bishop , et al. · 2023

This Report describes the design and prototyping of an array of rare-Earth permanent magnets to form a stellarator. This effort was motivated by the hypothesis that the usage of permanent magnets, rather than electromagnetic coils with com…

A novel scheme for error field correction in permanent magnet stellarators Open

A. Rutkowski, K. Hammond, Caoxiang Zhu, D. Gates, Amelia Chambliss · 2022

Stellarators offer a promising path towards fusion reactors, but their design and construction are complicated by stringent tolerance requirements on highly complex 3D coils. A potential way to simplify the engineering requirements for ste…

Design of an arrangement of cubic magnets for a quasi-axisymmetric stellarator experiment Open

K. Hammond, Caoxiang Zhu, Keith Corrigan, D. Gates, R. Lown , et al. · 2022

The usage of permanent magnets to shape the confining magnetic field of a stellarator has the potential to reduce or eliminate the need for non-planar coils. As a proof-of-concept for this idea, we have developed a procedure for designing …

PM4Stell: A prototype permanent magnet stellarator structure Open

Caoxiang Zhu, K. Hammond, Adam Rutkowski, Keith Corrigan, D Bishop , et al. · 2022

Permanent magnets provide a possible solution to simplify complicated stellarator coils. A prototype permanent magnet stellarator structure, PM4Stell, has been funded to demonstrate the technical feasibility of using permanent magnets to c…

Simpler optimized stellarators using permanent magnets Open

Tony Qian, M. C. Zarnstorff, D Bishop, A. Chamblis, A. Dominguez , et al. · 2022

A first-of-a-kind optimized stellarator for confining plasma has been designed and is being constructed with planar circular coils and permanent magnets composed of identical elements. The equilibrium is optimized to be quasi-axisymmetric …

Design of an arrangement of cubic magnets for a quasi-axisymmetric stellarator experiment Open

K. Hammond, Caoxiang Zhu, Keith Korrigan, D. Gates, Robert Lown , et al. · 2022

The usage of permanent magnets to shape the confining field of a stellarator has the potential to reduce or eliminate the need for non-planar coils. As a proof-of-concept for this idea, we have developed a procedure for designing an array …

A novel scheme for error field correction in permanent magnet stellarators Open

Adam Rutkowski, K. Hammond, Caoxiang Zhu, D. Gates, Amelia Chambliss · 2022

hiddenSymmetries/simsopt: Graph Optimization framework for all of simsopt class Open

Bharat Medasani, Florian Wechsung, Matt Landreman, R. Jorge, Andrew Giuliani , et al. · 2021

This release extends the graph Optimizable framework to surface and MHD classes. Changes Implemented: Enhancements to graph Optimizable class to keep order of the dependent functions ObjectiveFailure added to LeastSquaresProblem Tolerances…

Stellarator coil design using cubic splines for improved access on the outboard side Open

N. Lonigro, Caoxiang Zhu · 2021

In recent years many efforts have been undertaken to simplify coil designs for stellarators due to the difficulties in fabricating non-planar coils. The FOCUS code removes the need for a winding surface and represents the coils as arbitrar…

Improving the stellarator through advances in plasma theory Open

C. C. Hegna, D. T. Anderson, A. Bader, Torrin Bechtel, A. Bhattacharjee , et al. · 2021

Improvements to the stellarator concept can be realized through advancements in theoretical and computational plasma physics. Herein, recent advances are reported in the topical areas of: (1) improved energetic ion confinement, (2) the imp…

hiddenSymmetries/simsopt: New Coil-n-Currents, Derivatives, and stage II coil optimization Open

Bharat Medasani, Florian Wechsung, Matt Landreman, R. Jorge, Andrew Giuliani , et al. · 2021

Courtesy @florianwechsung, this release introduces new Coil, Current, and Derivative classes and allows for stage-II optimization A new Coil class that represents a Curve and a Current. A list of Coil objects is now passed to BiotSavart (…

SIMSOPT: A flexible framework for stellarator optimization Open

Matt Landreman, Bharat Medasani, Florian Wechsung, Andrew Giuliani, R. Jorge , et al. · 2021

A stellarator is a magnetic field configuration used to confine plasma, and it is a candidate configuration for fusion energy, as well as a general charged particle trap.A stellarator's magnetic field is typically produced using electromag…

Stellarator optimization for good magnetic surfaces at the same time as quasisymmetry Open

Matt Landreman, Bharat Medasani, Caoxiang Zhu · 2021

A method is demonstrated to optimize a stellarator's geometry to eliminate magnetic islands and achieve other desired physics properties at the same time. For many physics quantities that have been used in stellarator optimization, includi…

hiddenSymmetries/simsopt: v0.4.2 Released Open

Bharat Medasani, Florian Wechsung, R. Jorge, Andrew Giuliani, Elizabeth S. Paul , et al. · 2021

This release introduces\n\n1) The ability to compute fieldlines as well as particle trajectories using the guiding center approximation. \n Credits to Florian Wechsung. \n2) A quadratic-flux minimizing surface solver, defined as the minimi…

Computation of the Biot-Savart Line Integral Open

Nick McGreivy, Caoxiang Zhu, Lee M. Gunderson, S. R. Hudson · 2021

One common approach to computing the magnetic field produced by a filamentary current-carrying coil is to approximate the coil as a series of straight segments. The Biot-Savart field from each straight segment is known analytically. Howeve…

Physics basis for design of 3D coils in tokamaks Open

N.C. Logan, Caoxiang Zhu, Jong-Kyu Park, S.M. Yang, Qiming Hu · 2021

Recent progress in 3D tokamak modeling is now leveraged to create a conceptual design of new external 3D field coils for the DIII-D tokamak. In this work generalized perturbed equilibrium code is used to determine optimally efficient spect…

Caoxiang Zhu YOU? Author Swipe