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GPU-accelerated computing of three-dimensional solar wind background

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Science China Earth Sciences 2013年第11期56卷 1864-1880页

作者： FENG XueShang ZHONG DingKun xiang changqing ZHANG Yao SIGMA Weather Group State Key Laboratory for Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences

High-performance computational models are required to make the real-time or faster than rea^-time numerical prediction of adverse space weather events and their influence on the geospace environment. The main objective in this article is to explore the application of programmable graphic processing units （GPUs） to the numerical space weather modeling for the study of solar wind background that is a crucial part in the numerical space weather modeling. GPU programming is realized for our Solar-Interplanetary-CESE MHD model （SIP-CESE MHD model） by numerically studying the solar corona/interplanetary so- lar wind. The global solar wind structures are obtained by the established GPU model with the magnetic field synoptic data as input. Meanwhile, the time-dependent solar surface boundary conditions derived from the method of characteristics and the mass flux limit are incorporated to couple the observation and the three-dimensional （3D） MHD model. The simulated evolu- tion of the global structures for two Carrington rotations 2058 and 2062 is compared with solar observations and solar wind measurements t^om spacecraft near the Earth. The MHD model is also validated by comparison with the standard potential field source surface （PFSS） model. Comparisons show that the MHD results are in good overall agreement with coronal and interplanetary structures, including the size and distribution of coronal holes, the position and shape of the streamer belts, and the transition of the solar wind speeds and magnetic field polarities.

关键词： space weather modeling SIP-CESE MHD model GPU computing

Advance of Interplanetary Physics Study in China:2008-2010

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空间科学学报 2010年第5期30卷 427-444页

作者： Zhao Xinhua xiang changqing State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190

Interplanetary physics study is an important ingredient in space weather *** progress this aspect has been achieved by the space physics community of China in recent *** brief report summarizes the latest advances of the interplanetary physics research in China during the period of *** report includes solar corona and solar wind,interplanetary transients,energetic particles,MHD simulation,space plasma,and prediction methods for physical phenomena originating from both solar corona and interplanetary space.

关键词：行星际空间空间物理学中国空间等离子体太阳日冕组成部分空间天气高能粒子

Three Dimensional Simulation of the Steady Solar Wind in Carrington Rotation 1935

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空间科学学报 2006年第1期26卷 8-13页

作者： xiang changqing FENG Xueshang YAO Jiusheng Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080

A three-dimensional MHD simulation is conducted to study the steady solar wind in Carrington Rotation (CR) 1935 by using the three-dimensional numerical magnetohydrodynamic (MHD) model introduced by Feng et al The numerical results demonstrate that the neutral current sheet has two peaks and two valleys, which is consistent with the result of PFSS model at Wilcox Solar Observatory (WSO). The obtained proton number density at 2.5 Rs is of the same order of magnitude as the result estimated from K-coronal brightness during the CRs 1733-1742 in 1983 made by Wei et al. The radial velocity profile along heliocentric distance is consistent with that of low solar wind speed deduced by Sheeley and Wang et al. However, it is not able to reproduce the fast-speed flow in coronal holes and slow solar wind in streamers because of oversimplified energy equation adopted in our model. Future efforts must be made to remedy this deficiency.

关键词：三维模拟太阳风空间物理地球物理

Thermal transport in lithium-ion battery: A micro perspective for thermal management

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Frontiers of physics 2022年第1期17卷 143-153页

作者： changqing xiang Cheng-Wei Wu Wu-Xing Zhou Guofeng Xie Gang Zhang College of Information Science and Engineering Jishou UniversityJishou416000China School of Materials Science and Engineering&Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion Hunan University of Science and TechnologyXiangtan411201China Institute of High Performance Computing A*STAR Singapore138632Singapore

In recent years, lithium ion (Li-ion) batteries have served as significant power sources in portable electronic devices and electric vehicles because of their high energy density and rate capability. There are growing concerns towards the safety of Li-ion batteries, in which thermal conductivities of anodes, cathodes, electrolytes and separator play key roles for determining the thermal energy transport in Li-ion battery. In this review, we summarize the state-of-the-art studies on the thermal conductivities of commonly used anodes, cathodes, electrolytes and separator in Li-ion batteries, including both theoretical and experimental reports. First, the thermal conductivities of anodes and cathodes are discussed, and the effects of delithiation degree and temperature of materials are also discussed. Then, we review the thermal conductivities of commonly used electrolytes, especially on solid electrolytes. Finally, the basic concept of interfacial thermal conductance and simulation methods are presented, as well as the interfacial thermal conductance between separator and cathodes. This perspective review would provide atomic perspective knowledge to understand thermal transport in Li-ion battery, which will be beneficial to the thermal management and temperature control in electrochemical energy storage devices.

关键词： lithium ion batteries thermal management phonon transport interfacial thermal transport amorphous materials

Enhanced thermoelectric properties in two-dimensional monolayer Si2BN by adsorbing halogen atoms

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Chinese Physics B 2021年第3期30卷 41-47页

作者： Cheng-Wei Wu changqing xiang Hengyu Yang Wu-Xing Zhou Guofeng Xie Baoli Ou Dan Wu School of Materials Science and Engineering&Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion Hunan University of Science and TechnologyXiangtan 411201China College of Information Science and Engineering Jishou UniversityJishou 416000China School of Physics and Electronic Science Changsha University of Science and TechnologyChangsha 410114China

Using the first principles calculation and Boltzmann transport theory, we study the thermoelectric properties of Si2BNadsorbing halogen atoms (Si2BN-4X, X = F, Cl, Br, and I). The results show that the adsorption of halogen atoms cansignificantly regulate the energy band structure and lattice thermal conductivity of Si2BN. Among them, Si2BN-4I has thebest thermoelectric performance, the figure of merit can reach 0.50 K at 300 K, which is about 16 times greater than that ofSi2BN. This is because the adsorption of iodine atoms not only significantly increases the Seebeck coefficient due to banddegeneracy, but also rapidly reduces the phonon thermal conductivity by enhancing phonon scattering. Our work proves theapplication potential of Si2BN-based crystals in the field of thermoelectricity and the effective method for metal crystals toopen bandgaps by adsorbing halogens.

关键词： density functional theory thermoelectric effects transport properties electronic structure

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时变行星际太阳风模拟及其结果评估

地球物理学报 2019年第1期62卷 1-18页

作者：李会超冯学尚向长青中国科学院国家空间科学中心北京100190 中国科学院大学北京100049

背景太阳风对于地球附近的空间环境有着重要的影响,三维磁流体力学太阳风模型是背景太阳风研究和预报的重要工具.通过太阳光球磁场数据驱动的边界条件,我们发展了一个时变的行星际三维磁流体力学太阳风模型.使用这个模型,我们模拟了200... 详细信息

背景太阳风对于地球附近的空间环境有着重要的影响,三维磁流体力学太阳风模型是背景太阳风研究和预报的重要工具.通过太阳光球磁场数据驱动的边界条件,我们发展了一个时变的行星际三维磁流体力学太阳风模型.使用这个模型,我们模拟了2008年全年的行星际背景太阳风,分析了该年太阳风结构全球特征的演化和行星际局地观测与日冕结构间的联系.实现了一套太阳风连续参数和特征结构模拟质量的定量评估方法.对2008年模拟结果的评估表明,模型较好地重现了背景太阳风的大尺度特征.模拟与观测速度间的相关性系数达到了0.6以上,行星际磁场强度与观测吻合得较好,捕获了全部的行星际磁场极性反转和82.76%的流相互作用区,行星际磁场极性反转的误报率仅为6.67%,流相互作用区的误报率仅为11.11%,两种结构的到达时间误差在1天左右.同时,通过综合分析评估结果,我们明确了高速流结构、内边界磁场分布等模型在进一步改进中需要重点注意的问题.

关键词：磁流体力学太阳风数值模拟数据驱动结果评估

A comparative study on 3-D solar wind structure observed by Ulysses and MHD simulation

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Science Bulletin 2005年第7期50卷 672-678页

作者： FENG Xueshang, xiang changqing, ZHONG Dingkun & FAN Quanlin SIGMA Weather Group, Key Laboratory of Space Weather Key Labo- ratory of Geospace Environment and Geodesy, Ministry of Education, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, China SIGMA Weather Group Key Laboratory of Space Weather Key Labo- ratory of Geospace Environment and Geodesy Ministry of Education Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China

During Ulysses’ first rapid pole-to-pole transit from September 1994 to June 1995, its observations showed that middle- or high-speed solar winds covered all latitudes except those between ?20° and +20° near the ecliptic plane, where the velocity was 300―450 km/s. At poleward 40°, however, only fast solar winds at the speed of 700―870 km/s were observed. In addition, the transitions from low-speed wind to high-speed wind or vice versa were abrupt. In this paper, the large-scale structure of solar wind observed by Ulysses near solar minimum is simulated by using the three-dimensional numerical MHD model. The model com- bines TVD Lax-Friedrich scheme and MacCormack II scheme and decomposes the calculation region into two re- gions: one from 1 to 22 Rs and the other from 18 Rs to 1 AU. Based on the observations of the solar photospheric magnetic field and an addition of the volumetric heating to MHD equations, the large-scale solar wind structure mentioned above is reproduced by using the three-dimensional MHD model and the numerical results are roughly consistent with Ulysses’ observations. Our simulation shows that the initial magnetic field topology and the addition of volume heating may govern the bimodal structure of solar wind observed by Ulysses and also demonstrates that the three-dimensional MHD numerical model used here is efficient in modeling the large-scale solar wind structure.

关键词： Ulysses observation solar wind structure numerical simulation.

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电场驱动的日冕数值模拟中时变边界条件研究

地球物理学报 2023年第10期66卷 4009-4025页

作者：吕佳锟柳晓静向长青中国科学院国家空间科学中心空间天气学国家重点实验室北京100190 中国科学院大学地球与行星科学学院北京100049

时变边界条件的处理对于数据驱动的日冕太阳风建模研究十分重要.本文基于特征边界条件,将松弛型无反射边界处理应用到三维磁流体力学(Magnetohydrodynamics,MHD)方程中,发展出一种自洽的、以切向电场作为数据驱动的时变边界条件,并将其... 详细信息

时变边界条件的处理对于数据驱动的日冕太阳风建模研究十分重要.本文基于特征边界条件,将松弛型无反射边界处理应用到三维磁流体力学(Magnetohydrodynamics,MHD)方程中,发展出一种自洽的、以切向电场作为数据驱动的时变边界条件,并将其应用于时变日冕太阳风的模拟中.为验证该时变边界条件的有效性,本文连续模拟研究了2187—2189三个卡林顿周的日冕太阳风结构.通过将模拟结果与SOHO、STEREO等卫星的观测结果进行对比研究,发现基于该时变边界条件的日冕太阳风的模拟可以较好地反映出日冕太阳风的大尺度结构及其演化过程,且模拟得到的太阳风参数与卫星观测结果较为吻合.说明本文所发展的时变边界条件可以有效地模拟数据驱动的时变日冕太阳风.

关键词：日冕磁流体力学边界条件电场驱动

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Observation of topological charge transformations in acoustic vortex using passive periodic systems

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 140-147页

作者： Di-Chao Chen Xie Liu changqing Xu Da-Jian Wu Ying Cheng Xiao-Jun Liu School of Physics and Technology Nanjing Normal University Key Laboratory of Modern Acoustics School of Physics Nanjing University

Vortex transmutation utilizes a periodic system, which not only enables the alteration of the topological charge(TC) of unstable input vortices but also facilitates their transformation into stable structures. This approach is crucial for investigating the characteristics of vortices in various wave systems. Here, we achieve acoustic vortex TC transmutation by employing a welldesigned dual-structured plate external system(DPES). The interactions between the acoustic vortex and the finite-order discrete rotational symmetry lead to the transformation of its topological charge when complete rotational symmetry is broken to Nthorder discrete symmetry. Our results experimentally demonstrate the acoustic vortex TC transmutation based on passive artificial structures, enabling numerous applications in particle manipulation and information multiplexing as well as advancing our understanding and control over free-space acoustic vortices.

关键词： acoustic vortex topological charge transformation artificial structure