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A parareal algorithm for a highly oscillating Vlasov-Poisson system with reduced models for the coarse solving

COMPUTERS & MATHEMATICS WITH APPLICATIONS 2023年 130卷 137-148页

作者： Grigori, Laura Hirstoaga, Sever A. Salomon, Julien Sorbonne Univ Project Team ALPINES Inria F-75589 Paris 12 France Univ Paris CNRS Lab Jacques Louis LJLL L F-75589 Paris 12 France Sorbonne Univ Project Team ANGE Inria F-75589 Paris 12 France

In this paper, we introduce a new strategy for solving highly oscillatory two-dimensional Vlasov-Poisson systems by means of a specific version of the parareal algorithm. The novelty consists in using reduced models, obtained from the two-scale convergence theory, for the coarse solving. The reduced models are useful to approximate the original Vlasov-Poisson model at a low computational cost since they are free of high oscillations. Both models are numerically solved in a particle-in-cell framework. We illustrate this strategy with numerical experiments based on long time simulations of a charged beam in a focusing channel and under the influence of a rapidly oscillating external electric field. On the basis of computing times, we provide an analysis of the efficiency of the parareal algorithm in terms of speedup.

关键词： Vlasov-Poisson system Two-scale convergence Multi-scale models particle-in-cell method Parareal algorithm Parareal speedup

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Spatial core-edge coupling of the particle-in-cell gyrokinetic codes GEM and XGC

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PHYSICS OF PLASMAS 2020年第12期27卷

作者： Cheng, Junyi Dominski, Julien Chen, Yang Chen, Haotian Merlo, Gabriele Ku, Seung-Hoe Hager, Robert Chang, Choong-Seock Suchyta, Eric D'Azevedo, Eduardo Ethier, Stephane Sreepathi, Sarat Klasky, Scott Jenko, Frank Bhattacharjee, Amitava Parker, Scott Univ Colorado Dept Phys Boulder CO 80309 USA Princeton Plasma Phys Lab 100 Stellarator Rd Princeton NJ 08543 USA Univ Texas Austin Austin TX 78712 USA Oak Ridge Natl Lab Comp Sci & Math Div Oak Ridge TN 37831 USA Max Planck Inst Plasma Phys Boltzmannstr 2 D-85748 Garching Germany

Two existing particle-in-cell gyrokinetic codes, GEM for the core region and XGC for the edge region, have been successfully coupled with a spatial coupling scheme at the interface in a toroidal geometry. A mapping technique is developed for transferring data between GEM's structured and XGC's unstructured meshes. Two examples of coupled simulations are presented to demonstrate the coupling scheme. The optimization of GEM for graphics processing unit is also presented.

关键词： Plasma dynamics particle-in-cell method Plasma confinement Computer simulation Tokamaks

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Numerical investigation for shape controlling of ultrathin electron layer

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LASER AND particle BEAMS 2012年第3期30卷 489-495页

作者： Tan, F. Wu, B. Zhu, B. Han, D. Zhao, Z. -Q. Hong, W. Cao, L. -F. Gu, Y. -Q. China Acad Engn Phys Res Ctr Laser Fus Mianyang Sichuan Peoples R China

To control the shape of the ultra-thin electron layer produced by directly interaction of ultrahigh contrast laser with ultrathin foil target, we investigated the spacial distribution and temporal evolution of electron layers produced from single and double foil targets through two-dimensional particle-in-cell simulations. Results show that electron layers produced from double foil targets can fly with unperturbed velocity for a much longer time than in the single foil case, which can be explained by the integrated contribution of charge separation field from both the two foils. Further studies show that through adjusting the foil expansion, electron layers with different shapes can be obtained. Detailed studies on the forming process of layers show that electron momentum distribution evolves rapidly along with the pump laser and then the vanishing of electron transverse momentum induced by the reflected laser results in the forming of layer shape. So different foil expansion corresponds to different moments that reflected laser interact with electron layer, when the electron transverse momentum distribution is different. After the reflected laser interact with electron layer, the resultant longitude momentum distribution will finally lead to various electron layer shapes.

关键词： Laser-driven electron acceleration Laser-plasma interactions Nanofilm particle-in-cell method Ultrathin electron layer

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Extended particle absorber for efficient modeling of intense laser-solid interactions

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PHYSICS OF PLASMAS 2021年第11期28卷 1-11页

作者： Miller, Kyle G. May, Joshua Fiuza, Frederico Mori, Warren B. Univ Calif Los Angeles Dept Phys & Astron Los Angeles CA 90095 USA SLAC Natl Accelerator Lab Menlo Pk CA 94025 USA

An extended thermal particle boundary condition is devised to more efficiently and accurately model laser-plasma interactions in overdense plasmas. particle-in-cell simulations of such interactions require many particles per cell, and a large region of background plasma is often necessary to correctly mimic a semi-infinite plasma and avoid electron refluxing from a truncated plasma. For long-pulse lasers of many picoseconds, such constraints can become prohibitively expensive. Here, an extended particle boundary condition (absorber) is designed that instantaneously stops and re-emits energetic particles streaming toward the simulation boundary over a defined region, allowing sufficient time and space for a suitably cool return current to develop in the background plasma. Tunable parameters of the absorber are explained, and simulations using the absorber with a 3-ps laser are shown to accurately reproduce those of a causally separated boundary while requiring only 20% the number of particles.

关键词： Topics Dynamical systems Plasma heating Energy conservation Plasma temperature Probability theory particle beams Electrodynamics particle-in-cell method Plasma properties and parameters Lasers

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Dynamics of nanometer-scale foil targets irradiated with relativistically intense laser pulses

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LASER AND particle BEAMS 2011年第4期29卷 383-388页

作者： Hoerlein, R. Steinke, S. Henig, A. Rykovanov, S. G. Schnuerer, M. Sokollik, T. Kiefer, D. Jung, D. Yan, X. Q. Tajima, T. Schreiber, J. Hegelich, M. Nickles, P. V. Zepf, M. Tsakiris, G. D. Sandner, W. Habs, D. Max Born Inst D-12489 Berlin Germany Max Planck Inst Quantum Opt Garching Germany Univ Munich Fak Phys D-8046 Garching Germany Los Alamos Natl Lab Los Alamos NM USA Peking Univ State Key Lab Nucl Phys & Technol Beijing Peoples R China JAEA Photomed Res Ctr Kyoto Japan GIST Kwangju South Korea Queens Univ Belfast Dept Phys & Astron Belfast Antrim North Ireland

In this paper we report on an experimental study of high harmonic radiation generated in nanometer-scale foil targets irradiated under normal incidence. The experiments constitute the first unambiguous observation of odd-numbered relativistic harmonics generated by the v x B component of the Lorentz force verifying a long predicted property of solid target harmonics. Simultaneously the observed harmonic spectra allow in-situ extraction of the target density in an experimental scenario which is of utmost interest for applications such as ion acceleration by the radiation pressure of an ultraintense laser.

关键词： Frequency conversion Laser-driven acceleration Laser-plasma interaction particle-in-cell method Plasma-generated coherent radiation

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Dynamics of plasma-surface interactions in chemically active plasmas

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VACUUM 2009年第1期84卷 97-100页

作者： Cerny, Pavel Novak, Stanislav Hrach, Rudolf Univ JE Purkyne Fac Sci Dept Phys Usti Nad Labem 40096 Czech Republic Charles Univ Prague Fac Math & Phys Dept Surface & Plasma Sci CR-18000 Prague 8 Czech Republic

The contribution presents results of computer simulations describing the interaction between a low-temperature multicomponent plasma and an immersed metal substrate. For this purpose two models were prepared. The first model is designed to follow the volume processes in oxygen-containing electronegative plasma. The technique used was the macroscopic kinetic approach with a kinetic scheme consisting of more than 100 reactions. As a result, the concentrations of individual charged species for various discharge parameters were derived. These species are used as input parameters in the second model based on the particle-in-cell-Monte Carlo Collision (PIC-MCC) particle simulation technique. The sheath structure of the multicomponent plasma containing more than one type of negative as well as positive ions and the fluxes of individual charged species impinging the oxidized substrates were studied with the help of this model. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Plasma-surface interaction Simulation methods particle-in-cell method

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Analysis of the beam halo in negative ion sources by using 3D3V PIC code

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REVIEW OF SCIENTIFIC INSTRUMENTS 2016年第2期87卷 02B124-02B124页

作者： Miyamoto, K. Nishioka, S. Goto, I. Hatayama, A. Hanada, M. Kojima, A. Hiratsuka, J. Naruto Univ Educ 748 NakashimaNaruto Cho Naruto Tokushima 7728502 Japan Keio Univ Fac Sci & Technol Kohoku Ku 3-14-1 Hiyoshi Yokohama Kanagawa 2238522 Japan Japan Atom Energy Agcy 801-1 Mukouyama Naka Ibaraki 3190913 Japan

The physical mechanism of the formation of the negative ion beam halo and the heat loads of the multi-stage acceleration grids are investigated with the 3D PIC (particle in cell) simulation. The following physical mechanism of the beam halo formation is verified: The beam core and the halo consist of the negative ions extracted from the center and the periphery of the meniscus, respectively. This difference of negative ion extraction location results in a geometrical aberration. Furthermore, it is shown that the heat loads on the first acceleration grid and the second acceleration grid are quantitatively improved compared with those for the 2D PIC simulation result. (C) 2015 AIP Publishing LLC.

关键词： particle-in-cell method Halo Negative ion beams Magnetic fields Negative ion sources

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Recent progress in plasma modelling at INFN-LNS

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REVIEW OF SCIENTIFIC INSTRUMENTS 2016年第2期87卷 02A505-02A505页

作者： Neri, L. Castro, G. Torrisi, G. Galata, A. Mascali, D. Celona, L. Gammino, S. Ist Nazl Fis Nucl Lab Nazl Sud Via S Sofia 62 I-95125 Catania Italy Univ Mediterranea Reggio Calabria Via Graziella I-89100 Reggio Di Calabria Italy Ist Nazl Fis Nucl Lab Nazl Legnaro Viale Univ 2 I-35020 Padua Italy

At Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), the development of intense ion and proton sources has been supported by a great deal of work on the modelling of microwave generated plasmas for many years. First, a stationary version of the particle-in-cell code was developed for plasma modelling starting from an iterative strategy adopted for the space charge dominated beam transport simulations. Electromagnetic properties of the plasma and full-waves simulations are now affordable for non-homogenous and non -isotropic magnetized plasma via "cold" approximation. The effects of Coulomb collisions on plasma particles dynamics was implemented with the Langevin formalism, instead of simply applying the Spitzer 90 collisions through a Monte Carlo technique. A wide database of different cross sections related to reactions occurring in a hydrogen plasma was implemented. The next step consists of merging such a variety of approaches for retrieving an "as-a-whole" picture of plasma dynamics in ion sources. The preliminary results will be summarized in the paper for a microwave discharge ion source designed for intense and high quality proton beams production, proton source for European Spallation Source project. Even if the realization of a predictive software including the complete processes involved in plasma formation is still rather far, a better comprehension of the source behavior is possible and so the simulations may support the optimization phase. (C) 2015 AIP Publishing LLC.

关键词： Microwave sources Ion sources Plasma waves particle-in-cell method Chemical reaction cross sections

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SIMULATION OF THE PROCESSES OF FORMATION OF A DUST CLOUD IN A VACUUM AND IN THE ABSENCE OF GRAVITATION

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JOURNAL OF ENGINEERING PHYSICS AND THERMOPHYSICS 2018年第1期91卷 252-259页

作者： Avdeev, A. V. Boreisho, A. S. Ivakin, S. V. Moiseev, A. A. Savin, A. V. Sokolov, E. I. Smirnov, P. G. Moscow Inst Aviat Technol 4 Volokolamskoe HighwayA-80GSP-3 Moscow 125993 Russia DF Ustinov Balt State Tech Univ VOENMEKH 1st Krasnoarmeiskaya Str 1 St Petersburg 190005 Russia Lit A NPP Laser Syst 34 Svyazi Str St Petersburg Oez Noidorf Russia Lit BD AO Concern Struinye Tekhnol 47 Stachek Ave St Petersburg 198097 Russia Petra Velikogo Petersburg State Polytech Univ 29 Politekhn Skaya Str St Petersburg 195251 Russia

This article is devoted to the simulation of the processes of formation of dust clouds in the absence of gravitation, which is necessary for understanding the processes proceeding in dust clusters in outer space, upper planetary atmosphere, and on the surface of space objects, as well as for evaluating the possibilities of creating disperse structures with given properties. The chief aim of the simulation is to determine the general laws of the dynamics of the dust cloud at the initial stage of its formation. With the use of the original approach based on the particle-in-cell method that permits investigating the mechanics of large ensembles of particles on contemporary computational platforms, we consider the mechanics of a dusty medium in the process of its excitation in a closed container due to the vibration of the walls, and then in the process of particle scattering when the container opens in outer space. The main formation mechanisms of a dust formation have been elucidated, and the possibilities of mathematical simulation for predicting spatial and time characteristics of disperse structures have been shown.

关键词： dust cloud particle-in-cell method disperse structures mathematical simulation parallel calculations Maxwell distribution

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Modeling of Long-Range Intra- and Inter-Species Charged particle Collisions for PIC Simulations

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Communications in Computational Physics 2010年第5期7卷 877-903页

作者： D.D’Andrea C.-D.Munz R.Schneider Forschungszentrum Karlsruhe-in der Helmholtz-Gemeinschaft Institut fur Kern-und EnergietechnikPF 3640D-76021 KarlsruheGermany Institut fur Aerodynamik und Gasdynamik Universitat StuttgartPfaffenwaldring 21D-70550 StuttgartGermany Forschungszentrum Karlsruhe-in der Helmholtz-Gemeinschaft Institut fur Hochleistungsimpuls und MikrowellentechnikPF 3640D-76021 KarlsruheGermany

In this paper we present the modelling of elastic intra-species electron-electron and inter-species electron-ion scattering in a plasma on the basis of the FokkerPlanck collision *** into account the equivalence of this operator with a stochastic differential equation,we propose a particle-in-cell based approach for the numerical solution of the Fokker-Planck collision *** we will see,the introduced numerical concept allows the simulation of the collisional relaxation process in a fully self-consistent fashion.

关键词： Coulomb collisions in plasmas collisional relaxation Fokker-Planck equation stochastic differential equation particle-in-cell method

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