Computer Physics Communications最新文献

{"title":"Redistribution of the post-reaction internal energies in DSMC using quantum-kinetic model","authors":"Chi-Ho Chou,&nbsp;Kuo-Long Pan","doi":"10.1016/j.cpc.2025.109641","DOIUrl":"10.1016/j.cpc.2025.109641","url":null,"abstract":"<div><div>The Direct Simulation Monte Carlo (DSMC) method has been largely adopted to analyze problems regarding hypersonic, non-equilibrium, and microscopic flows. In this study, we investigate the thermal-chemical effects on combustion at the microscopic scale using this particle collision-based method. It is realized that the existing Larsen-Borgnakke (L-B) model dealing with transfers of various internal energies cannot provide valid solutions for the reactions, and consequently the system fails to reach thermal equilibrium. To overcome this problem, we propose a modified quantum-kinetic (Q-K) model and corresponding redistribution algorithm to satisfy the required detailed balance, based on the solver dsmcFoam+ in the open-source software OpenFOAM. This allows a more straightforward way to handle post-energy redistribution in chemical reactions in comparison to those of the other methods, thus reducing the computational cost and manipulation. To verify the accuracy, spontaneous combustion of premixed <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> is simulated, which includes polyatomic reactions and non-equilibrium processes, followed by three-dimensional simulation for the Mars Pathfinder probe. Compared with the L-B redistribution method, substantial improvement and excellent solutions to the issues are demonstrated by using the new approach, paving the way for accurate and efficient studies of complex problems involving polyatomic chemical reactions and non-equilibrium processes.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"314 ","pages":"Article 109641"},"PeriodicalIF":7.2,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143934609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generalizable models of magnetic hysteresis via physics-aware recurrent neural networks","authors":"Abhishek Chandra ,&nbsp;Taniya Kapoor ,&nbsp;Bram Daniels ,&nbsp;Mitrofan Curti ,&nbsp;Koen Tiels ,&nbsp;Daniel M. Tartakovsky ,&nbsp;Elena A. Lomonova","doi":"10.1016/j.cpc.2025.109650","DOIUrl":"10.1016/j.cpc.2025.109650","url":null,"abstract":"<div><div>Hysteresis is a ubiquitous phenomenon in magnetic materials; its modeling and identification are crucial for understanding and optimizing the behavior of electrical machines. Such machines often operate under uncertain conditions, necessitating modeling methods that can generalize across unobserved scenarios. Traditional recurrent neural architectures struggle to generalize hysteresis patterns beyond their training domains. This paper mitigates the generalization challenge by introducing a physics-aware recurrent neural network approach to model and generalize the hysteresis manifesting in sequentiality and history-dependence. The proposed method leverages ordinary differential equations (ODEs) governing the phenomenological hysteresis models to update hidden recurrent states. The effectiveness of the proposed method is evaluated by predicting generalized scenarios, including first-order reversal curves and minor loops. The results demonstrate robust generalization to previously untrained regions, even with noisy data, an essential feature that hysteresis models must have. The results highlight the advantages of integrating physics-based ODEs into recurrent architectures, including superior performance over traditional methods in capturing the complex, nonlinear hysteresis behaviors in magnetic materials. The codes and data related to the paper are at <span><span>github.com/chandratue/HystRNN</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"314 ","pages":"Article 109650"},"PeriodicalIF":7.2,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143921718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"STREAmS-2.1: Supersonic turbulent accelerated Navier-Stokes solver version 2.1","authors":"Francesco Salvadore ,&nbsp;Giulio Soldati ,&nbsp;Alessandro Ceci ,&nbsp;Giacomo Rossi ,&nbsp;Antonio Memmolo ,&nbsp;Giacomo Della Posta ,&nbsp;Davide Modesti ,&nbsp;Srikanth Sathyanarayana ,&nbsp;Matteo Bernardini ,&nbsp;Sergio Pirozzoli","doi":"10.1016/j.cpc.2025.109652","DOIUrl":"10.1016/j.cpc.2025.109652","url":null,"abstract":"<div><div>We present STREAmS-2.1, an updated version of the flow solver STREAmS <span><span>[1]</span></span>, lastly updated in Bernardini et al. Comput. Phys. Commun. 285 (2023) 108644. STREAmS-2.1 merges the features of the curvilinear solver FLEW <span><span>[2]</span></span> which is able to simulate three canonical cases, namely the circular arc channel, the curved boundary layer and the airfoil case. Moreover, three new backends are included, i.e., OpenMP (for CPUs), HIP (for AMD GPUs) and OpenMP-offload (tested on Intel GPUs but potentially portable). Finally, in situ visualization layer based on Catalyst2 technology is integrated into the solver to reduce the visualization effort, especially for huge computational grids.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"314 ","pages":"Article 109652"},"PeriodicalIF":7.2,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143911659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distributed-parallel proper orthogonal/dynamic mode decompositions of large flow data","authors":"Vilas Shinde","doi":"10.1016/j.cpc.2025.109644","DOIUrl":"10.1016/j.cpc.2025.109644","url":null,"abstract":"<div><div>High-fidelity computational fluid dynamics (CFD) simulations produce large databases, which are typically stored on either centralized or distributed machines. Eigen/Singular value decompositions are some of the early-stage and most useful decompositions. The more popular proper orthogonal decomposition (POD) and dynamics mode decomposition (DMD) of fluid flows are essentially based on the eigen/singular value decomposition algorithms. Although there exist very efficient and parallel eigen/singular value solvers, most of them perform poorly when handling large data particularly in distributed settings, and often resort to a partial estimation of eigen/singular value spectra. In this paper, we present a memory-efficient and highly-scalable POD and DMD procedures in distributed-parallel settings, where the parallel DMD algorithm is an improved tall-and-skinny QR (TSQR) DMD algorithm. A Large Eddy Simulations (LES) database of a fully turbulent Shock Wave Boundary Layer Interaction (SBLI) at Mach 2.7 and Reynolds number of <span><math><mn>54</mn><mo>,</mo><mn>600</mn></math></span> based on the inflow boundary layer thickness is employed, first, to evaluate the performance and accuracy of the algorithms, and second, to elucidate some of the three-dimensional coherent flow features of the SBLI pertaining to POD/DMD. The selected POD/DMD modes of the LES flowfields exhibit full 3D flow features, such as, the streamwise-elongated Görtler-like vortices and high-frequency acoustic packets that are physically relevant to the SBLI dynamics.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109644"},"PeriodicalIF":7.2,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The design, verification, and applications of Hotspice: A Monte Carlo simulator for artificial spin ice","authors":"Jonathan Maes ,&nbsp;Diego De Gusem ,&nbsp;Ian Lateur ,&nbsp;Jonathan Leliaert ,&nbsp;Aleksandr Kurenkov ,&nbsp;Bartel Van Waeyenberge","doi":"10.1016/j.cpc.2025.109643","DOIUrl":"10.1016/j.cpc.2025.109643","url":null,"abstract":"<div><div>We present Hotspice, a Monte Carlo simulation software designed to capture the dynamics and equilibrium states of Artificial Spin Ice (ASI) systems with both in-plane (IP) and out-of-plane (OOP) geometries. An Ising-like model is used where each nanomagnet is represented as a macrospin, with switching events driven by thermal fluctuations, magnetostatic interactions, and external fields. To improve simulation accuracy, we explore the impact of several corrections to this model, concerning for example the calculation of the dipole interaction in IP and OOP ASI, as well as the impact of allowing asymmetric rather than symmetric energy barriers between stable states. We validate these enhancements by comparing simulation results with experimental data for pinwheel and kagome ASI lattices, demonstrating how these corrections enable a more accurate simulation of the behavior of these systems. We finish with a demonstration of ‘clocking’ in pinwheel and OOP square ASI as an example of reservoir computing.</div></div><div><h3>Program summary</h3><div><em>Program title: Hotspice</em></div><div><em>CPC Library link to program files:</em> <span><span>https://doi.org/10.17632/9c3rx36jvn.1</span><svg><path></path></svg></span></div><div><em>Developer's repository link:</em> <span><span>https://github.com/bvwaeyen/Hotspice</span><svg><path></path></svg></span></div><div><em>Licensing provisions:</em> GPLv3</div><div><em>Programming language:</em> Python 3</div><div><em>Nature of problem:</em> To tailor the complex phenomena in Artificial Spin Ice for a specific purpose, simulations are key to rapidly assess whether a given combination of system parameters will yield a desirable result. Therefore, a simulator capable of simulating systems containing thousands of magnets is needed, ideally requiring a minimal amount of input parameters. This is particularly important for use cases such as reservoir computing, where system-scale dynamics are of primary interest.</div><div><em>Solution method:</em> Hotspice approximates each single-domain nanomagnet as an Ising spin, associating energies with its various states and accounting for the magnetostatic interaction between all magnets. By calculating switching rates using the Néel-Arrhenius model, or flipping magnets based on the Metropolis-Hastings algorithm, the dynamics of ASI can be calculated for large arrays and over experimentally relevant timescales.</div><div><em>Additional comments including restrictions and unusual features:</em> While Hotspice is well-suited for large-scale ASI simulations, it relies on higher-level approximations which do not account for the detailed internal magnetization dynamics within individual magnets. To improve simulation accuracy, several model variants have been implemented which differ in their calculation of the magnetostatic interactions, the use of symmetric versus asymmetric energy barriers, and their choice of update algorithm.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109643"},"PeriodicalIF":7.2,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards a complete task-based implementation of a 3D particle-in-cell code: Performance studies and benchmarks","authors":"J.J. Silva-Cuevas ,&nbsp;M. Zych ,&nbsp;K. Peyen ,&nbsp;I. Kabadshow ,&nbsp;M. Lobet","doi":"10.1016/j.cpc.2025.109647","DOIUrl":"10.1016/j.cpc.2025.109647","url":null,"abstract":"<div><div>This article investigates different programming models for miniPIC, a Particle-In-Cell mini-app, to improve overall scalability. An innovative implementation of a fully asynchronous task-based implementation of a 3D Particle-In-Cell code miniPIC is presented for the first time. The task-based model has been specially implemented in the particle-in-cell code via the backend OpenMP and the library Eventify. Four physical studies were selected as benchmarks: thermal plasma, plasma beam diffusion, a laser colliding with a plasma beam sphere, and thermal plasma with an imbalanced artificial operator. Besides, different parametric studies were designed to measure the scalability of the implementation to varying numbers of cores and various physical conditions. The current parametric studies were performed in an Intel cascade lake-based machine and an AMD EPYC-based machine to measure scalability performance on different architectures.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109647"},"PeriodicalIF":7.2,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient computation of the magnetic field created by a toroidal volumetric current of convex cross section with application to the study of the magnetic confinement in tokamaks","authors":"Miguel Camacho ,&nbsp;Rafael R. Boix ,&nbsp;Diego J. Cruz-Zabala ,&nbsp;Joaquín Galdón-Quiroga ,&nbsp;Juan M. Ayllón-Guerola ,&nbsp;Eleonora Viezzer","doi":"10.1016/j.cpc.2025.109642","DOIUrl":"10.1016/j.cpc.2025.109642","url":null,"abstract":"<div><div>In this paper we present an efficient approach for the numerical computation of the static vector potential and the poloidal magnetic field of a toroidal volumetric current with arbitrary convex cross section. The standard integral expressions for both the vector potential and the magnetic field include singularities that have a deleterious effect in the computation of these integrals. In order to handle these singularities, we first introduce a change of variables to polar coordinates with origin at the observation point that makes it possible to remove the singularities of the integrands thanks to the Jacobian factor. Then, two different numerical integration methods are applied to the resulting integrals: Ma-Rokhlin-Wandzura quadrature rules and the double exponential quadrature rule. Both methods efficiently handle the singularities in the derivative of the integrand for the integrals of the vector potential and the magnetic field, and the advantages and disadvantages of each method are discussed. The results obtained for the vector potential and magnetic field are validated by comparing with closed-form results existing for the vector potential and magnetic field of a circular loop and an infinite cylinder, and good agreement is found. Then, the magnetic field code is used to model the plasma toroidal current in a tokamak nuclear fusion reactor, and it is shown that the combined magnetic field of the plasma current and that of the poloidal and toroidal coils leads to magnetic confinement of the charged particles existing in the plasma.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109642"},"PeriodicalIF":7.2,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"POLARIS: The POLArized RadIation Simulator for Mie scattering in optically thick dusty plasmas","authors":"Julia Kobus ,&nbsp;Stefan Reißl ,&nbsp;Moritz Lietzow-Sinjen ,&nbsp;Alexander Bensberg ,&nbsp;Andreas Petersen ,&nbsp;Franko Greiner ,&nbsp;Sebastian Wolf","doi":"10.1016/j.cpc.2025.109645","DOIUrl":"10.1016/j.cpc.2025.109645","url":null,"abstract":"<div><div>POLARIS is a 3D Monte-Carlo radiative transfer code written in C++ for simulating the Mie scattering of laser light in optically thick nanodusty plasmas. Originally developed for astrophysical applications, POLARIS has been adapted to address the specific needs of the plasma physics community. To achieve this, a given number of photon packages characterized by their traveling direction <span><math><mover><mrow><mi>d</mi></mrow><mrow><mo>→</mo></mrow></mover></math></span>, wavelength <em>λ</em>, intensity, and polarization state in terms of the Stokes vector <span><math><mover><mrow><mi>S</mi></mrow><mrow><mo>→</mo></mrow></mover></math></span> is generated to mimic the emission of a laser source with a Gaussian intensity distribution. These photon packages are then tracked along their probabilistic paths through the particle cloud, with scattering processes determined stochastically based on probability density distributions derived from the optical properties of the dust particles. POLARIS allows simulations for arbitrary wavelengths and grain sizes, as long as the far-field approximation holds. This paper introduces this adapted version of POLARIS to the plasma physics community, highlighting its capabilities for modeling light scattering in dusty plasmas and serving as a comprehensive reference for its application. In doing so, POLARIS provides a powerful tool for the in-situ analysis of optically thick dusty plasmas.</div></div><div><h3>Program summary</h3><div><em>Program Title:</em> POLARIS</div><div><em>CPC Library link to program files:</em> <span><span>https://doi.org/10.17632/8d3jm3x29t.1</span><svg><path></path></svg></span></div><div><em>Developer's repository link:</em> <span><span>https://github.com/polaris-MCRT/POLARIS</span><svg><path></path></svg></span></div><div><em>Licensing provisions:</em> GPLv3</div><div><em>Programming language:</em> C++, Python 3</div><div><em>Nature of problem:</em> Simulating Mie scattering in dense dusty plasmas to enable in-situ analysis of these systems.</div><div><em>Solution method:</em> Tracing the random paths of photon packages through a three dimensional grid filled with dust particles making stochastic decisions on scattering processes based on probability density distributions given by the optical properties of the dust particles.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109645"},"PeriodicalIF":7.2,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143894784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FLOW36: A spectral solver for phase-field based multiphase turbulence simulations on heterogeneous computing architectures","authors":"Alessio Roccon ,&nbsp;Giovanni Soligo ,&nbsp;Alfredo Soldati","doi":"10.1016/j.cpc.2025.109640","DOIUrl":"10.1016/j.cpc.2025.109640","url":null,"abstract":"&lt;div&gt;&lt;div&gt;We present FLOW36, a GPU-ready solver for interface-resolved simulations of multiphase turbulence. The simulation framework relies on the coupling of direct numerical simulation of turbulence, used to describe the flow field, with a phase-field method, used to describe the shape and deformation of a deformable interface and the presence of surfactants. An additional transport equation for a passive scalar can be solved to describe heat transfer in multiphase turbulence. The governing equations are solved in a cuboid domain bounded by two walls along the wall-normal direction where no-slip, free-slip or fixed/moving wall boundary conditions can be applied, while periodicity is applied along the streamwise and spanwise directions. The numerical method relies on a pseudo-spectral approach where Fourier series (periodic directions) and Chebyshev polynomials (wall-normal direction) are used to discretize the governing equations in space. Equations are advanced in time using an implicit-explicit scheme. From a computational perspective, FLOW36 relies on a multilevel parallelism. The first level of parallelism relies on the message-passing interface (MPI). A second level of parallelism uses OpenACC directives and cuFFT libraries; this second level is used to accelerate the code execution when heterogeneous computing infrastructures are targeted. In this work, we present the numerical method and we discuss the main implementation strategies, with particular reference to the MPI and OpenACC directives and code portability, performance and maintenance strategies. FLOW36 is released open source under the GPLv3 license.&lt;/div&gt;&lt;/div&gt;&lt;div&gt;&lt;h3&gt;Program summary&lt;/h3&gt;&lt;div&gt;&lt;em&gt;Program Title:&lt;/em&gt; FLOW36&lt;/div&gt;&lt;div&gt;&lt;em&gt;CPC Library link to program files:&lt;/em&gt; &lt;span&gt;&lt;span&gt;https://doi.org/10.17632/ygcn7dsb9k.1&lt;/span&gt;&lt;svg&gt;&lt;path&gt;&lt;/path&gt;&lt;/svg&gt;&lt;/span&gt;&lt;/div&gt;&lt;div&gt;&lt;em&gt;Developer's repository link:&lt;/em&gt; &lt;span&gt;&lt;span&gt;https://github.com/MultiphaseFlowLab/FLOW36&lt;/span&gt;&lt;svg&gt;&lt;path&gt;&lt;/path&gt;&lt;/svg&gt;&lt;/span&gt;&lt;/div&gt;&lt;div&gt;&lt;em&gt;Licensing provisions:&lt;/em&gt; GPLv3 License&lt;/div&gt;&lt;div&gt;&lt;em&gt;Programming language:&lt;/em&gt; Modern Fortran&lt;/div&gt;&lt;div&gt;&lt;em&gt;Nature of problem:&lt;/em&gt; Solving the three-dimensional incompressible Navier–Stokes equations in a Cartesian domain configured for open and closed channel flows. A phase-field method is used to describe the shape and topological changes of deformable interfaces. Additional equations are included to account for the presence of surfactants, heat transfer problems and for the transport of point-wise Lagrangian particles.&lt;/div&gt;&lt;div&gt;&lt;em&gt;Solution method:&lt;/em&gt; The system of governing equations is advanced in time using an implicit-explicit strategy while the governing equations are discretized in space using a pseudo-spectral approach: Fourier series are employed along the homogeneous directions while Chebyshev polynomial along the wall-normal direction. A first order explicit Euler method is used to advance the equations for the Lagrangian particles motion. A two-","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109640"},"PeriodicalIF":7.2,"publicationDate":"2025-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A robust fourth-order finite-difference discretization for the strongly anisotropic transport equation in magnetized plasmas","authors":"L. Chacón,&nbsp;J. Hamilton,&nbsp;N. Krasheninnikova","doi":"10.1016/j.cpc.2025.109646","DOIUrl":"10.1016/j.cpc.2025.109646","url":null,"abstract":"<div><div>We propose a second-order temporally implicit, fourth-order-accurate spatial discretization scheme for the strongly anisotropic heat transport equation characteristic of hot, fusion-grade plasmas. Following Du Toit et al. (2018) <span><span>[17]</span></span>, the scheme transforms mixed-derivative diffusion fluxes (which are responsible for the lack of a discrete maximum principle) into nonlinear advective fluxes, amenable to nonlinear-solver-friendly monotonicity-preserving limiters. The scheme enables accurate multi-dimensional heat transport simulations with up to seven orders of magnitude of heat-transport-coefficient anisotropies with low cross-field numerical error pollution and excellent algorithmic performance, with the number of linear iterations scaling very weakly with grid resolution and grid anisotropy, and scaling with the square-root of the implicit timestep. We propose a multigrid preconditioning strategy based on a lower-order approximation that renders the scheme efficient and scalable under grid refinement. Several numerical tests are presented that display the expected spatial convergence rates and strong algorithmic performance, including fully nonlinear magnetohydrodynamics simulations of kink instabilities in a Bennett pinch in 2D helical geometry and of ITER in 3D toroidal geometry.</div></div>","PeriodicalId":285,"journal":{"name":"Computer Physics Communications","volume":"313 ","pages":"Article 109646"},"PeriodicalIF":7.2,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}