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Pseudo mesh for adjoint weight flux in predictor corrector quasi static kinetics calculation in monte carlo code RMC

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Pseudo mesh for adjoint weight flux in predictor corrector q...

2018 International Conference on physics of Reactors: Reactor physics Paving the Way Towards More Efficient Systems, PHYSOR 2018

作者： Shang, Xiaotong Xu, Qi Wang, Kan Department of Engineering Physics Tsinghua University Beijing 100084 China Institute of Applied Physics and Computational Mathematics Beijing100084 China

ISBN: (纸本)9781713808510

The continuous energy Monte Carlo (MC) method for arbitrary geometry is playing a more and more important role in reactor physics analysis including both static (criticality and burnup) and transient calculations with the development of high performance computing (HPC) platform. Considering the high calculation time cost of the direct simulation method, predictor-corrector quasi-static (PCQS) method has been implemented in Monte Carlo Code RMC. In PCQS method, the neutron angular flux is factorized into the amplitude function and shape function. The calculation procedure consists of transient fixed source MC calculation in each macro time step which calculates the power distribution and estimates the point-kinetics parameters and the point-kinetics calculation in each micro time step. In this work, the transient fixed source MC calculation is solved by the modified fission source iteration method and a kind of pseudo mesh for the adjoint weight flux is proposed for the estimation of point-kinetics parameters. Rather than multi-group adjoint flux calculation, the adjoint weight flux in each mesh can be obtained from the Iterated fission probability (IFP) method implemented in RMC before which is suitable for continuous energy Monte Carlo eigenvalue calculation scheme. Then the point-kinetics equation is solved with the fourth order Runge-Kutta method. For code verification, the two-dimensional TWIGL problem is calculated and compared with the results of deterministic code MPACT, which shows a good agreement. © 2018 International Conference on physics of Reactors, PHYSOR 2018: Reactor physics Paving the Way Towards More Efficient Systems. All rights reserved.

关键词： Monte Carlo methods

A spacetime finite elements method to solve the dirac equation

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arXiv 2021年

作者： Sundermann, Rylee Lim, Hyun Waybright, Jace Kimn, Jung-Han Department of Mathematics and Statistics South Dakota State University BrookingsSD57007 United States Computational Physics and Methods Group Los Alamos National Laboratory Los AlamosNM87545 United States Center for Theoretical Astrophysics Los Alamos National Laboratory Los AlamosNM87545 United States Applied Computer Science Group Los Alamos National Laboratory Los AlamosNM87545 United States Princeton Plasma Physics Laboratory Princeton University PrincetonNJ08543 United States

In this work, a fully implicit numerical approach based on space-time finite element method is presented to solve the Dirac equation in 1 (space) + 1 (time), 2 + 1, and 3 + 1 dimensions. We utilize PETSc/Tao library to implement our linear system and for using Krylov subspace based solvers such as GMRES. We demonstrate our method by analyzing several different cases including plane wave solution, Zitterbewegung, and Klein paradox. Parallel performance of this implementation is also presented. © 2021, CC BY.

关键词： Finite element method

Recent research progress of laser plasma interactions in Shenguang laser facilities

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Matter and Radiation at Extremes 2019年第5期4卷 38-49页

作者： Tao Gong Liang Hao Zhichao Li Dong Yang Sanwei Li Xin Li Liang Guo Shiyang Zou Yaoyuan Liu Xiaohua Jiang Xiaoshi Peng Tao Xu Xiangming Liu Yulong Li Chunyang Zheng Hongbo Cai Zhanjun Liu Jian Zheng Zhebin Wang Qi Li Ping Li Rui Zhang Ying Zhang Fang Wang Deen Wang Feng Wang Shenye Liu Jiamin Yang Shaoen Jiang Baohan Zhang Yongkun Ding Research Center of Laser Fusion China Academy of Engineering PhysicsMianyangSichuan 621900People’s Republic of China Institute of Applied Physics and Computational Mathematics Beijing 100088People’s Republic of China CAS Key Laboratory of Geospace Environment and Department of Engineering and Department of Engineering and Applied Physics University of Science and Technology of ChinaHefeiAnhui 230027People’s Republic of China

Wereport experimental research on laser plasma interaction(LPI)conducted in Shenguang laser facilities during the past ten *** research generally consists of three phases:(1)developing platforms for LPI research in mm-scale plasma with limited drive energy,where both gasbag and gas-filled hohlraum targets are tested;(2)studying the effects of beam-smoothing techniques,such as continuous phase plate and polarization smoothing,on the suppression of LPI;and(3)exploring the factors affecting LPI in integrated implosion experiments,which include the laser intensity,gas-fill pressure,size of the laser-entrance hole,and interplay between different beam *** obtained in each phase will be presented and discussed in detail.

关键词： laser polarization smoothing

Design and Numerical Analysis of an Open-Circuit Low-Speed Wind Tunnel

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Design and Numerical Analysis of an Open-Circuit Low-Speed W...

2019 Novel Intelligent and Leading Emerging Sciences Conference, NILES 2019

作者： Seddik, Ahmed Ahmed, Marawan Ayman, Mohamed Guaily, Amr School of Engineering and Applied Sciences Nile University Mechanical Engineering Program Shaikh Zayed City12588 Egypt School of Engineering and Applied Sciences Nile University Shaikh Zayed City12588 Egypt Engineering Mathematics and Physics Department Faculty of Engineering Cairo University Giza12613 Egypt

ISBN: (纸本)9781728131733

The design and numerical analysis of a 3D open-circuit, low-speed, with a maximum velocity of 20 m/s in the test section, wind tunnel is presented. Two diffusers' angels are numerically tested in order to reduce the pumping power of the fan. The proposed design is analyzed using three-dimensional, turbulent, incompressible flow using ANSYS FLUENT. Numerical results show that the velocity as well as the pressure are uniform in the test section and no vortices are formed in the diffuser section which affirms the success of the proposed design. © 2019 IEEE.

关键词： Numerical analysis

The SRG/eROSITA All-Sky Survey: Dark Energy Survey Year 3 Weak Gravitational Lensing by eRASS1 selected Galaxy Clusters

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arXiv 2024年

作者： Grandis, S. Ghirardini, V. Bocquet, S. Garrel, C. Mohr, J.J. Liu, A. Kluge, M. Kimmig, L. Reiprich, T.H. Alarcon, A. Amon, A. Artis, E. Bahar, Y.E. Balzer, F. Bechtol, K. Becker, M.R. Bernstein, G. Bulbul, E. Campos, A. Carnero Rosell, A. Carrasco Kind, M. Cawthon, R. Chang, C. Chen, R. Chiu, I. Choi, A. Clerc, N. Comparat, J. Cordero, J. Davis, C. Derose, J. Diehl, H.T. Dodelson, S. Doux, C. Drlica-Wagner, A. Eckert, K. Elvin-Poole, J. Everett, S. Ferte, A. Gatti, M. Giannini, G. Giles, P. Gruen, D. Gruendl, R.A. Harrison, I. Hartley, W.G. Herner, K. Huff, E.M. Kleinebreil, F. Kuropatkin, N. Leget, P.F. Maccrann, N. McCullough, J. Merloni, A. Myles, J. Nandra, K. Navarro-Alsina, A. Okabe, N. Pacaud, F. Pandey, S. Prat, J. Predehl, P. Ramos, M. Raveri, M. Rollins, R.P. Roodman, A. Ross, A.J. Rykoff, E.S. Sanchez, C. Sanders, J. Schrabback, T. Secco, L.F. Seppi, R. Sevilla-Noarbe, I. Sheldon, E. Shin, T. Troxel, M. Tutusaus, I. Varga, T.N. Wu, H. Yanny, B. Yin, B. Zhang, X. Zhang, Y. Alves, O. Bhargava, S. Brooks, D. Burke, D.L. Carretero, J. Costanzi, M. da Costa, L.N. Pereira, M.E.S. De Vicente, J. Desai, S. Doel, P. Ferrero, I. Flaugher, B. Friedel, D. Frieman, J. García-Bellido, J. Gutierrez, G. Hinton, S.R. Hollowood, D.L. Honscheid, K. James, D.J. Jeffrey, N. Lahav, O. Lee, S. Marshall, J.L. Menanteau, F. Ogando, R.L.C. Pieres, A. Plazas Malagón, A.A. Romer, A.K. Sanchez, E. Schubnell, M. Smith, M. Suchyta, E. Swanson, M.E.C. Tarle, G. Weaverdyck, N. Weller, J. Universität Innsbruck Institut für Astro- und Teilchenphysik Technikerstr. 25/8 Innsbruck6020 Austria Max Planck Institute for Extraterrestrial Physics Giessenbachstrasse 1 Garching85748 Germany Faculty of Physics Ludwig-Maximilians-Universität München Scheinerstr. 1 Munich81679 Germany Universität Bonn Auf dem Hügel 71 Bonn53121 Germany Kavli Institute for Cosmology University of Cambridge Mading- ley Road CambridgeCB3 0HA United Kingdom Institute of Astronomy University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom Physics Department University of Wisconsin-Madison MadisonWI53706 United States Argonne National Laboratory 9700 South Cass Avenue LemontIL60439 United States Department of Physics and Astronomy University of Pennsylvania PhiladelphiaPA19104 United States Department of Physics Carnegie Mellon University PittsburghPA15312 United States Instituto de Astrofisica de Canarias Tenerife La LagunaE-38205 Spain Laboratório Interinstitucional de e-Astronomia - LIneA Rua Gal. José Cristino 77 RJ Rio de Janeiro20921-400 Brazil Universidad de La Laguna Dpto. Astrofísica Tenerife La LagunaE-38206 Spain Center for Astrophysical Surveys National Center for Supercom- puting Applications 1205 West Clark St. UrbanaIL61801 United States Department of Astronomy University of Illinois at Urbana-Champaign 1002 W. Green Street UrbanaIL61801 United States Physics Department William Jewell College LibertyMO64068 United States Department of Astronomy and Astrophysics University of Chicago ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Department of Physics Duke University DurhamNC27708 United States Department of Physics National Cheng Kung University Tainan70101 Taiwan NASA Goddard Space Flight Center 8800 Greenbelt Rd Green- belt MD20771 United States IRAP Université de Toulouse CNRS UPS CNES Toulouse France Jodrell Bank Center f

Context. Number counts of galaxy clusters across redshift are a powerful cosmological probe, if a precise and accurate reconstruction of the underlying mass distribution is performed - a challenge called mass calibration. With the advent of wide and deep photometric surveys, weak gravitational lensing by clusters has become the method of choice to perform this measurement. Aims. We measure and validate the weak gravitational lensing (WL) signature in the shape of galaxies observed in the first 3 years of the Dark Energy Survey (DES Y3) caused by galaxy clusters and groups selected in the first all-sky survey performed by SRG (Spectrum Roentgen Gamma)/eROSITA (eRASS1). These data are then used to determine the scaling between X-ray photon count rate of the clusters and their halo mass and redshift. Methods. We empirically determine the degree of cluster member contamination in our background source sample. The individual cluster shear profiles are then analysed with a Bayesian population model that self-consistently accounts for the lens sample selection and contamination, and includes marginalization over a host of instrumental and astrophysical systematics. To quantify the accuracy of the mass extraction of that model, we perform mass measurements on mock cluster catalogs with realistic synthetic shear profiles. This allows us to establish that hydro-dynamical modelling uncertainties at low lens redshifts (z © 2024, CC BY.

关键词： Calibration

CONVERGENCE OF A TIME-STEPPING SCHEME TO THE FREE BOUNDARY IN THE SUPERCOOLED STEFAN PROBLEM

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arXiv 2020年

作者： Kaushansky, Vadim Reisinger, Christoph Shkolnikov, Mykhaylo Song, Zhuo Qun Department of Mathematics University of California Los AngelesCA90095 United States Mathematical Institute University of Oxford Andrew Wiles Building Radcliffe Observatory Quarter OxfordOX2 6GG United Kingdom ORFE Department Bendheim Center for Finance and Program in Applied & Computational Mathematics Princeton University Princeton NJ08544 United States Department of Mathematics Princeton University Princeton NJ08544 United States

The supercooled Stefan problem and its variants describe the freezing of a supercooled liquid in physics, as well as the large system limits of systemic risk models in finance and of integrate-and-fire models in neuroscience. Adopting the physics terminology, the supercooled Stefan problem is known to feature a finite-time blow-up of the freezing rate for a wide range of initial temperature distributions in the liquid. Such a blow-up can result in a discontinuity of the liquid-solid boundary. In this paper, we prove that the natural Euler time-stepping scheme applied to a probabilistic formulation of the supercooled Stefan problem converges to the liquid-solid boundary of its physical solution globally in time, in the Skorokhod M1 topology. In the course of the proof, we give an explicit bound on the rate of local convergence for the time-stepping scheme. We also run numerical tests to compare our theoretical results to the practically observed convergence *** Codes 80A22, 35B44, 65N20, 60H30 Copyright © 2020, The Authors. All rights reserved.

关键词： Supercooling

Evolution of the self-injection process in the transition of an LWFA from self-modulation to blowout regime

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arXiv 2020年

作者： Kumar, Prabhat Yu, Kwangmin Zgadzaj, Rafal Downer, Michael Petrushina, Irina Samulyak, Roman Litvinenko, Vladimir Vafaei-Najafabadi, Navid Department of Applied Mathematics and Statistics Stony Brook University Stony BrookNY11794 United States Computational Science Initiative Brookhaven National Laboratory UptonNY11973 United States Department of Physics University of Texas at Austin AustinTX78712 United States Department of Physics and Astronomy Stony Brook University Stony BrookNY11794 United States

Long wavelength infrared (LWIR) laser driven plasma wakefield accelerators are investigated here in the self-modulated laser wakefield acceleration (SM-LWFA) and blowout regimes using 3D Particle-in-Cell simulations. The simulation results show that in SM-LWFA regime, self-injection arises with wave breaking, whereas in the blowout regime, self-injection is not observed under the simulation conditions. The wave breaking process in SM-LWFA regime occurs at a field strength that is significantly below the 1D wave-breaking threshold. This process intensifies at higher laser power and plasma density and is suppressed at low plasma densities (≤ 1 × 1017 cm−3 here). The produced electrons show spatial modulations with a period matching that of the laser wavelength, which is a clear signature of direct laser acceleration (DLA). Copyright © 2020, The Authors. All rights reserved.

关键词： Modulation

Foundational Competencies and Responsibilities of a Research Software Engineer

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arXiv 2023年

作者： Goth, Florian Alves, Renato Braun, Matthias Castro, Leyla Jael Chourdakis, Gerasimos Christ, Simon Cohen, Jeremy Druskat, Stephan Erxleben, Fredo Grad, Jean-Noël Hagdorn, Magnus Hodges, Toby Juckeland, Guido Kempf, Dominic Lamprecht, Anna-Lena Linxweiler, Jan Löffler, Frank Martone, Michele Schwarzmeier, Moritz Seibold, Heidi Thiele, Jan Philipp Waldow, Harald von Wittke, Samantha Institute for Theoretical Physics and Astrophysics University of Würzburg Germany European Molecular Biology Laboratory Heidelberg Germany Cluster of Excellence IntCDC University of Stuttgart Germany ZB MED Information Centre for Life Sciences Cologne Germany School of Computation Information and Technology Technical University of Munich Garching Germany Institute for Parallel and Distributed Systems University of Stuttgart Stuttgart Germany Leibniz University Hannover Department of Cell Biology and Biophysics Computational Biology Germany Imperial College London London United Kingdom Institute for Software Technology Berlin Germany Humboldt-Universität zu Berlin Department of Computer Science Berlin Germany Helmholtz-Zentrum Dresden-Rossendorf Germany Institute for Computational Physics University of Stuttgart Germany Geschäftsbereich IT Charité Universitätsmedizin Berlin Germany The Carpentries United States Heidelberg University Scientific Software Center Germany Institute of Computer Science University of Potsdam Germany Technische Universität Braunschweig Germany Michael Stifel Center Jena Friedrich Schiller University Jena Germany Leibniz Supercomputing Centre Garching Germany Mathematical Modeling and Analysis TU Darmstadt Germany IGDORE Munich Germany Weierstrass Institute Berlin Germany Leibniz University Hannover Institute of Applied Mathematics Scientific Computing Hannover Germany Johann Heinrich von Thünen Institute Centre for Information Management Germany

The term Research Software Engineer, or RSE, emerged a little over 10 years ago as a way to represent individuals working in the research community but focusing on software development. The term has been widely adopted and there are a number of high-level definitions of what an RSE is. However, the roles of RSEs vary depending on the institutional context they work in. At one end of the spectrum, RSE roles may look similar to a traditional research role. At the other extreme, they resemble that of a software engineer in industry. Most RSE roles inhabit the space between these two extremes. Therefore, providing a straightforward, comprehensive definition of what an RSE does and what experience, skills and competencies are required to become one is challenging. In this community paper we define the broad notion of what an RSE is, explore the different types of work they undertake, and define a list of foundational competencies as well as values that outline the general profile of an RSE. Further research and training can build upon this foundation of skills and focus on various aspects in greater detail. We expect that graduates and practitioners will have a larger and more diverse set of skills than outlined here. On this basis, we elaborate on the progression of these skills along different dimensions. We look at specific types of RSE roles, propose recommendations for organisations, and give examples of future specialisations. An appendix details how existing curricula fit into this framework. © 2023, CC BY.

关键词： Computer aided software engineering

Simons Observatory: Constraining inflationary gravitational waves with multitracer B-mode delensing

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Physical Review D 2022年第2期105卷 023511-023511页

作者： Toshiya Namikawa Anton Baleato Lizancos Naomi Robertson Blake D. Sherwin Anthony Challinor David Alonso Susanna Azzoni Carlo Baccigalupi Erminia Calabrese Julien Carron Yuji Chinone Jens Chluba Gabriele Coppi Josquin Errard Giulio Fabbian Simone Ferraro Alba Kalaja Antony Lewis Mathew S. Madhavacheril P. Daniel Meerburg Joel Meyers Federico Nati Giorgio Orlando Davide Poletti Giuseppe Puglisi Mathieu Remazeilles Neelima Sehgal Osamu Tajima Grant Teply Alexander van Engelen Edward J. Wollack Zhilei Xu Byeonghee Yu Ningfeng Zhu Andrea Zonca Kavli Institute for the Physics and Mathematics of the Universe (WPI) UTIAS The University of Tokyo Kashiwa Chiba 277-8583 Japan Department of Applied Mathematics and Theoretical Physics University of Cambridge Wilberforce Road Cambridge CB3 0WA United Kingdom Institute of Astronomy Madingley Road Cambridge CB3 0HA United Kingdom Kavli Institute for Cosmology Cambridge Madingley Road Cambridge CB3 0HA United Kingdom Berkeley Center for Cosmological Physics Department of Physics University of California Berkeley California 94720 USA Lawrence Berkeley National Laboratory One Cyclotron Road Berkeley California 94720 USA Department of Physics University of Oxford Denys Wilkinson Building Keble Road Oxford OX1 3RH United Kingdom International School for Advanced Studies (SISSA) Via Bonomea 265 34136 Trieste Italy Institute for Fundamental Physics of the Universe (IFPU) Via Beirut 2 34151 Grignano (TS) Italy National Institute for Nuclear Physics (INFN) Sezione di Trieste Via Valerio 2 I-34127 Trieste Italy School of Physics and Astronomy Cardiff University The Parade Cardiff Wales CF24 3AA United Kingdom Université de Genève Département de Physique Théorique et CAP 24 Quai Ansermet CH-1211 Genève 4 Switzerland Research Center for the Early Universe School of Science The University of Tokyo Tokyo 113-0033 Japan Jodrell Bank Centre for Astrophysics Department of Physics and Astronomy University of Manchester Alan Turing Building Oxford Road Manchester M13 9PL United Kingdom Department of Physics University of Milano-Bicocca Piazza della Scienza 3 20126 Milano Italy Université de Paris CNRS Astroparticule et Cosmologie F-75013 Paris France Center for Computational Astrophysics Flatiron Institute 162 5th Avenue New York New York 10010 USA School of Physics and Astronomy Cardiff University The Parade Cardiff CF24 3AA United Kingdom Van Swinderen Institute for Particle Physics and Gravity University of Groningen Nijen- borgh 4 9747 AG Groningen Ne

We introduce and validate a delensing framework for the Simons Observatory (SO), which will be used to improve constraints on inflationary gravitational waves by reducing the lensing noise in measurements of the B modes in CMB polarization. SO will initially observe CMB by using three small aperture telescopes and one large-aperture telescope. While polarization maps from small-aperture telescopes will be used to constrain inflationary gravitational waves, the internal CMB lensing maps used to delens will be reconstructed from data from the large-aperture telescope. Since lensing maps obtained from the SO data will be noise dominated on subdegree scales, the SO lensing framework constructs a template for lensing-induced B modes by combining internal CMB lensing maps with maps of the cosmic infrared background from Planck as well as galaxy density maps from the LSST survey. We construct a likelihood for constraining the tensor-to-scalar ratio r that contains auto and cross spectra between observed B modes and the lensing B-mode template. We test our delensing analysis pipeline on map-based simulations containing survey nonidealities, but that, for this initial exploration, does not include contamination from Galactic and extragalactic foregrounds. We find that the SO survey masking and inhomogeneous and atmospheric noise have very little impact on the delensing performance, and the r constraint becomes σ(r)≈0.0015 which is close to that obtained from the idealized forecasts in the absence of the Galactic foreground and is nearly a factor of 2 tighter than without delensing. We also find that uncertainties in the external large-scale structure tracers used in our multitracer delensing pipeline lead to bias much smaller than the 1σ statistical uncertainties.

关键词： Cosmic microwave background Inflation Large scale structure of the Universe