Living reviews in computational astrophysics最新文献

Turbulence modelling in neutron star merger simulations 中子星合并模拟中的湍流建模

Living reviews in computational astrophysics Pub Date : 2024-02-05 DOI: 10.1007/s41115-023-00019-9

Davide Radice, Ian Hawke

引用次数: 1

Signatures of convection in the atmospheres of cool evolved stars 冷演化恒星大气中的对流特征

Living reviews in computational astrophysics Pub Date : 2024-01-31 DOI: 10.1007/s41115-024-00020-w

Andrea Chiavassa, K. Kravchenko, Jared A. Goldberg

引用次数: 0

Computational approaches to modeling dynamos in galaxies. 星系动力模型的计算方法。

Living reviews in computational astrophysics Pub Date : 2024-01-01 Epub Date: 2024-07-02 DOI: 10.1007/s41115-024-00021-9

Maarit J Korpi-Lagg, Mordecai-Mark Mac Low, Frederick A Gent

{"title":"Computational approaches to modeling dynamos in galaxies.","authors":"Maarit J Korpi-Lagg, Mordecai-Mark Mac Low, Frederick A Gent","doi":"10.1007/s41115-024-00021-9","DOIUrl":"10.1007/s41115-024-00021-9","url":null,"abstract":"Galaxies are observed to host magnetic fields with a typical total strength of around 15 <math><mi>μ</mi></math> G. A coherent large-scale field constitutes up to a few microgauss of the total, while the rest is built from strong magnetic fluctuations over a wide range of spatial scales. This represents sufficient magnetic energy for it to be dynamically significant. Several questions immediately arise: What is the physical mechanism that gives rise to such magnetic fields? How do these magnetic fields affect the formation and evolution of galaxies? In which physical processes do magnetic fields play a role, and how can that role be characterized? Numerical modelling of magnetized flows in galaxies is playing an ever-increasing role in finding those answers. We review major techniques used for these models. Current results strongly support the conclusion that field growth occurs during the formation of the first galaxies on timescales shorter than their accretion timescales due to small-scale turbulent dynamos. The saturated small-scale dynamo maintains field strengths at only a few percent of equipartition with turbulence. This is in contradiction with the observed magnitude of turbulent fields, but may be reconciled by the further contribution to the turbulent field of the large-scale dynamo. The subsequent action of large-scale dynamos in differentially rotating discs produces field strengths observed in low redshift galaxies, where it reaches equipartition with the turbulence and has substantial power at large scales. The field structure resulting appears consistent with observations including Faraday rotation and polarisation from synchrotron and dust thermal emission. Major remaining challenges include scaling numerical models toward realistic scale separations and Prandtl and Reynolds numbers.","PeriodicalId":74085,"journal":{"name":"Living reviews in computational astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11219407/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141536094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computational methods for collisional stellar systems 碰撞恒星系统的计算方法

Living reviews in computational astrophysics Pub Date : 2023-05-19 DOI: 10.1007/s41115-023-00018-w

R. Spurzem, A. Kamlah

引用次数: 0

Neutrino transport in general relativistic neutron star merger simulations. 一般相对论中子星合并模拟中的中微子输运。

Living reviews in computational astrophysics Pub Date : 2023-01-01 Epub Date: 2023-02-23 DOI: 10.1007/s41115-023-00016-y

Francois Foucart

{"title":"Neutrino transport in general relativistic neutron star merger simulations.","authors":"Francois Foucart","doi":"10.1007/s41115-023-00016-y","DOIUrl":"10.1007/s41115-023-00016-y","url":null,"abstract":"Numerical simulations of neutron star-neutron star and neutron star-black hole binaries play an important role in our ability to model gravitational-wave and electromagnetic signals powered by these systems. These simulations have to take into account a wide range of physical processes including general relativity, magnetohydrodynamics, and neutrino radiation transport. The latter is particularly important in order to understand the properties of the matter ejected by many mergers, the optical/infrared signals powered by nuclear reactions in the ejecta, and the contribution of that ejecta to astrophysical nucleosynthesis. However, accurate evolutions of the neutrino transport equations that include all relevant physical processes remain beyond our current reach. In this review, I will discuss the current state of neutrino modeling in general relativistic simulations of neutron star mergers and of their post-merger remnants. I will focus on the three main types of algorithms used in simulations so far: leakage, moments, and Monte-Carlo scheme. I will review the advantages and limitations of each scheme, as well as the various neutrino-matter interactions that should be included in simulations. We will see that the quality of the treatment of neutrinos in merger simulations has greatly increased over the last decade, but also that many potentially important interactions remain difficult to take into account in simulations (pair annihilation, oscillations, inelastic scattering).","PeriodicalId":74085,"journal":{"name":"Living reviews in computational astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9950247/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10805966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Simulations of common-envelope evolution in binary stellar systems: physical models and numerical techniques 双星系统共包络演化的模拟：物理模型和数值技术

Living reviews in computational astrophysics Pub Date : 2022-12-14 DOI: 10.1007/s41115-023-00017-x

F. Roepke, O. De Marco

引用次数: 8

Modeling cosmic reionization 模拟宇宙再电离

Living reviews in computational astrophysics Pub Date : 2022-08-03 DOI: 10.1007/s41115-022-00015-5

N. Gnedin, P. Madau

引用次数: 3

Well-balanced methods for computational astrophysics. 计算天体物理学的平衡方法。

Living reviews in computational astrophysics Pub Date : 2022-01-01 DOI: 10.1007/s41115-022-00014-6

Roger Käppeli

引用次数: 4

Simulations of cosmic ray propagation. 宇宙射线传播的模拟。

Living reviews in computational astrophysics Pub Date : 2021-01-01 Epub Date: 2021-07-26 DOI: 10.1007/s41115-021-00011-1

Michał Hanasz, Andrew W Strong, Philipp Girichidis

{"title":"Simulations of cosmic ray propagation.","authors":"Michał Hanasz, Andrew W Strong, Philipp Girichidis","doi":"10.1007/s41115-021-00011-1","DOIUrl":"https://doi.org/10.1007/s41115-021-00011-1","url":null,"abstract":"We review numerical methods for simulations of cosmic ray (CR) propagation on galactic and larger scales. We present the development of algorithms designed for phenomenological and self-consistent models of CR propagation in kinetic description based on numerical solutions of the Fokker-Planck equation. The phenomenological models assume a stationary structure of the galactic interstellar medium and incorporate diffusion of particles in physical and momentum space together with advection, spallation, production of secondaries and various radiation mechanisms. The self-consistent propagation models of CRs include the dynamical coupling of the CR population to the thermal plasma. The CR transport equation is discretized and solved numerically together with the set of MHD equations in various approaches treating the CR population as a separate relativistic fluid within the two-fluid approach or as a spectrally resolved population of particles evolving in physical and momentum space. The relevant processes incorporated in self-consistent models include advection, diffusion and streaming propagation as well as adiabatic compression and several radiative loss mechanisms. We discuss, applications of the numerical models for the interpretation of CR data collected by various instruments. We present example models of astrophysical processes influencing galactic evolution such as galactic winds, the amplification of large-scale magnetic fields and instabilities of the interstellar medium.","PeriodicalId":74085,"journal":{"name":"Living reviews in computational astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s41115-021-00011-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39580561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

PIC methods in astrophysics: simulations of relativistic jets and kinetic physics in astrophysical systems. 天体物理学中的PIC方法:天体物理系统中相对论性喷流和动力学物理的模拟。

Living reviews in computational astrophysics Pub Date : 2021-01-01 Epub Date: 2021-07-08 DOI: 10.1007/s41115-021-00012-0

Kenichi Nishikawa, Ioana Duţan, Christoph Köhn, Yosuke Mizuno

{"title":"PIC methods in astrophysics: simulations of relativistic jets and kinetic physics in astrophysical systems.","authors":"Kenichi Nishikawa, Ioana Duţan, Christoph Köhn, Yosuke Mizuno","doi":"10.1007/s41115-021-00012-0","DOIUrl":"https://doi.org/10.1007/s41115-021-00012-0","url":null,"abstract":"The Particle-In-Cell (PIC) method has been developed by Oscar Buneman, Charles Birdsall, Roger W. Hockney, and John Dawson in the 1950s and, with the advances of computing power, has been further developed for several fields such as astrophysical, magnetospheric as well as solar plasmas and recently also for atmospheric and laser-plasma physics. Currently more than 15 semi-public PIC codes are available which we discuss in this review. Its applications have grown extensively with increasing computing power available on high performance computing facilities around the world. These systems allow the study of various topics of astrophysical plasmas, such as magnetic reconnection, pulsars and black hole magnetosphere, non-relativistic and relativistic shocks, relativistic jets, and laser-plasma physics. We review a plethora of astrophysical phenomena such as relativistic jets, instabilities, magnetic reconnection, pulsars, as well as PIC simulations of laser-plasma physics (until 2021) emphasizing the physics involved in the simulations. Finally, we give an outlook of the future simulations of jets associated to neutron stars, black holes and their merging and discuss the future of PIC simulations in the light of petascale and exascale computing.","PeriodicalId":74085,"journal":{"name":"Living reviews in computational astrophysics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s41115-021-00012-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39580560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1