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Statistical study of magnetic holes in the upstream region of Mercury’s bow shock

Earth and Planetary Physics 2024年第2期8卷 326-337页

作者： GuoQiang Wang sudong xiao MingYu Wu YuanQiang Chen TieLong Zhang Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518055China Shenzhen Key Laboratory of Numerical Prediction for Space Storm Harbin Institute of TechnologyShenzhen 518055China Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences Center for Excellence in Comparative Planetology Hefei 230026China Space Research Institute Austrian Academy of SciencesGrazAustria

Magnetic holes are magnetic depression structures that exist widely in many plasma environments.The magnetic holes with durations of>1 s in the solar wind at Mercury’s orbit have drawn much attention,but the properties of the magnetic holes with shorter durations are still unclear.Here,we investigate the magnetic holes with durations of 0.1-100 s in the upstream region of Mercury’s bow shock based on observations by the MESSENGER(MErcury Surface,Space ENvironment,GEochemistry,and Ranging)spacecraft.They can be divided into two groups according to the distribution of their duration:small-duration magnetic holes(SDMHs,0.6 s).The duration of each group approximately obeys a log-normal distribution with a median of~0.25 s and 3 s,respectively.Approximately 1.7%(32.6%)of the SDMHs(LDMHs)reduce the magnetic field strength by more than 50%.For both groups,some structures have a linear or quasi-linear polarization,whereas others have an elliptical polarization.The magnetic hole events in both groups tend to have a higher rate of occurrence when the interplanetary magnetic field strength is weaker.Their occurrence rates are also affected by Mercury’s foreshock,which can increase(decrease)the occurrence rate of the SDMHs(LDMHs).This finding suggests that Mercury’s foreshock might be one source of the SDMHs and that the foreshock can destroy some LDMHs.These observations suggest that a new group of magnetic holes with durations of<0.6 s exist in the upstream region of Mercury’s bow shock.

关键词： magnetic hole solar wind Mercury foreshock

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In-flight calibration of the magnetometer on the Mars orbiter of Tianwen-1

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Science China(Technological Sciences) 2023年第8期66卷 2396-2405页

作者： ZOU ZhuXuan WANG YuMing ZHANG TieLong WANG GuoQiang xiao sudong PAN ZongHao ZHANG ZhouBin YAN Wei DU Yang CHI YuTian CHENG Long WU ZhiYong HAO XinJun LI YiRen LIU Kai CHEN ManMing SU ZhenPeng SHEN ChengLong XU MengJiao GUO JingNan School of Earth and Space Sciences/Deep Space Exploration Laboratory University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Space Research Institute Austrian Academy of SciencesGraz 8010Austria Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518055China National Astronomical Observatories Chinese Academy of SciencesBeijing 100080China Shanghai Institute of Satellite Engineering Shanghai 200240China Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230026China

Mars orbiter magnetometer(MOMAG)is one of seven science payloads onboard Tianwen-1’s orbiter.Unlike most of the satellites,Tianwen-1’s orbiter is not magnetically cleaned,and the boom where placed the magnetometer’s sensors is not long enough.These pose many challenges to the magnetic field data processing.In this study,we introduce the in-flight calibration process of the Tianwen-1/MOMAG.The magnetic interference including spacecraft generated dynamic field and the slowlychanging zero offsets are cleaned in sequence.Then the calibrated magnetic field data are compared with the data from the Mars atmosphere and volatile Evolutio N(MAVEN).We find that some physical structures in the solar wind are consistent between the two data sets,and the distributions of the magnetic field strength in the solar wind are very similar.These results suggest that the in-flight calibration of the MOMAG is successful and the MOMAG provides reliable data for scientific research.

关键词： magnetometer in-flight calibration Martian magnetic field Tianwen-1

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Responses of the field-aligned currents in the plasma sheet boundary layer to a geomagnetic storm

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Earth and Planetary Physics 2023年第5期7卷 558-564页

作者： YuanQiang Chen MingYu Wu YangJun Chen sudong xiao GuoQiang Wang TieLong Zhang Shenzhen Key Laboratory of Numerical Prediction for Space Storm Harbin Institute of TechnologyShenzhen 518055China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Chinese Academy of Sciences Center for Excellence in Comparative PlanetologyHefei 230026China Space Research Institute Austrian Academy of SciencesGraz 8042Austria

Geomagnetic storms can result in large magnetic field disturbances and intense currents in the magnetosphere and even on the ground.As an important medium of momentum and energy transport among the solar wind,magnetosphere,and ionosphere,field-aligned currents(FACs)can also be strengthened in storm times.This study shows the responses of FACs in the plasma sheet boundary layer(PSBL)observed by the Magnetospheric Multiscale(MMS)spacecraft in different phases of a large storm that lasted from May 27,2017,to May 29,2017.Most of the FACs were carried by electrons,and several FACs in the storm time also contained sufficient ion FACs.The FAC magnitudes were larger in the storm than in the quiet period,and those in the main phase were the strongest.In this case,the direction of the FACs in the main phase showed no preference for tailward or earthward,whereas the direction of the FACs in the recovery phase was mostly tailward.The results suggest that the FACs in the PSBL are closely related to the storm and could be driven by activities in the tail region,where the energy transported from the solar wind to the magnetosphere is stored and released as the storm is evolving.Thus,the FACs are an important medium of energy transport between the tail and the ionosphere,and the PSBL is a significant magnetosphere–ionosphere coupling region in the nightside.

关键词： field-aligned currents plasma sheet boundary layer geomagnetic storm

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Turbulence in the near-Venusian space: Venus Express observations

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Earth and Planetary Physics 2020年第1期4卷 82-87页

作者： sudong xiao MingYu Wu GuoQiang Wang Geng Wang YuanQiang Chen TieLong Zhang Harbin Institute of Technology Shenzhen 518055China Space Science Institute Macao University of Science and TechnologyMacao 999078China Chinese Academy of Sciences Key Laboratory of Geospace Environment University of Science and Technology of ChinaHefei 230026China Space Research Institute Austrian Academy of SciencesGraz 8042Austria

With Venus Express magnetic field measurements at 32 Hz from 2006 to 2012, we investigate statistically the magnetic fluctuations in the near-Venusian space. The global spatial distribution of their spectral scaling features is presented in MHD and kinetic regimes. It can be observed that turbulence is a common phenomenon in the solar wind in both regimes. The solar wind MHD turbulence is modified at the Venusian bow shock;MHD turbulence is absent in the Venusian magnetosheath but present at the magnetosheath boundary layer. Pre-existing kinetic turbulence from the far upstream solar wind is modified in the near solar wind region, while kinetic turbulence can be extensively observed throughout the Venusian magnetosheath and in some regions of the induced magnetosphere. Our results reveal that, in the near-Venusian space, energy cascade can be developed at the boundary between magnetosheath and wake, and the turbulence-related dissipation of magnetic energy occurs extensively in the magnetosheath and the induced magnetosphere.

关键词： turbulence near-Venusian space kinetic effects Venus Express

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The Mars orbiter magnetometer of Tianwen-1:in-flight performance and first science results

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Earth and Planetary Physics 2023年第2期7卷 216-228页

作者： YuMing Wang TieLong Zhang GuoQiang Wang sudong xiao ZhuXuan Zou Long Cheng ZongHao Pan Kai Liu XinJun Hao YiRen Li ManMing Chen ZhouBin Zhang Wei Yan ZhenPeng Su ZhiYong Wu ChengLong Shen YuTian Chi MengJiao Xu JingNan Guo Yang Du School of Earth and Space Sciences/Deep Space Exploration Laboratory University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Space Research Institute Austrian Academy of SciencesGrazAustria Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518055China National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China Institute of Deep Space Sciences Deep Space Exploration LaboratoryHefei 230026China Shanghai Institute of Satellite Engineering Shanghai 201109China

The Mars Orbiter MAGnetometer(MOMAG)is a scientific instrument onboard the orbiter of China’s first mission for Mars—Tianwen-1.Since November 13,2021,it has been recording magnetic field data from the solar wind to the magnetic pile-up region surrounding Mars.Here we present its in-flight performance and first science results,based on its first one and one-half months’data.Comparing these early MOMAG observations to the magnetic field data in the solar wind from NASA’s Mars Atmosphere and Volatile EvolutioN(MAVEN)mission,we report that the MOMAG magnetic field data are at the same level in magnitude,and describe the same magnetic structures with similar variations in three components.We recognize 158 clear bow shock(BS)crossings in these MOMAG data;their locations match well statistically with the modeled average BS.We also identify and compare five pairs of datasets collected when Tianwen-1’s orbiter and the MAVEN probe made simultaneous BS crossings.These BS crossings confirm the global shape of modeled BS,as well as the south-north asymmetry of the Martian BS.Two cases presented in this paper suggest that the BS is probably more dynamic at flank than near the nose.So far,MOMAG performs well,and provides accurate magnetic field vectors.MOMAG is continuously scanning the magnetic field surrounding Mars.Data from MOMAG’s measurements complement data from MAVEN and will undoubt edly advance our understanding of the plasma environment of Mars.

关键词： Mars magnetic field Tianwen-1 magnetometer bow shock

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火星磁鞘中小尺度磁洞发生率的观测

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地球物理学报 2023年第3期66卷 871-880页

作者：陈洋军吴明雨肖苏东王国强陈远强娄悦群杜爱民张铁龙哈尔滨工业大学(深圳)空间科学与应用技术研究院深圳518055 奥地利科学院空间研究所格拉茨A-8042 中国科学院比较行星学卓越创新中心合肥230026 中国科学院地质与地球物理研究所北京100029

小尺度磁洞是一种尺度通常小于质子回旋半径的磁结构,其特征是该结构内的磁场强度相对于周围环境存在一个显著的减弱.这种结构可能与能量转换和粒子加速、磁场重联和动力学尺度上的湍流密切相关.最近,小尺度磁洞在金星和火星磁鞘中被报... 详细信息

小尺度磁洞是一种尺度通常小于质子回旋半径的磁结构,其特征是该结构内的磁场强度相对于周围环境存在一个显著的减弱.这种结构可能与能量转换和粒子加速、磁场重联和动力学尺度上的湍流密切相关.最近,小尺度磁洞在金星和火星磁鞘中被报道.利用美国航天局MAVEN(Mars Atmosphere and Volatile EvolutioN)卫星4个月的观测数据,本文统计分析了火星磁鞘中的小尺度磁洞的发生率.统计结果表明,小尺度磁洞主要出现在环境磁场强度在4≤B≤12 nT,等离子体的速度在250~450 km·s^(-1),密度在3≤N≤12 cm^(-3)范围.在这个参数范围内,小尺度磁洞在背景太阳风流速相对更快、背景磁场相对更弱的时候发生率更高,且相对集中在背景密度在6~9 cm^(-3)之间.此外,靠近火星磁鞘中心的小尺度磁洞的发生率要高于磁鞘两侧,这意味着火星磁鞘可能是小尺度磁洞的一个源区.

关键词：火星磁鞘小尺度磁洞发生率

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Statistical properties of sub-ion magnetic holes in the solar wind at 1 AU

Statistical properties of sub-ion magnetic holes in the sola...

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2020年中国地球科学联合学术年会

作者： Lu Mi Guoqiang Wang Tielong Zhang sudong xiao Mingyu Wu Harbin Institute of Technology

Sub-ion magnetic holes are rich in the terrestrial plasma sheet and magnetosheath. Here, we statistically investigate 60 sub-ion magnetic holes in the solar wind at 1 AU using the high-resolution data measured by the Magnetospheric Multiscale mission. We find that they are observed with a duration of 0.1 – 0.5 s, and the lengths of their crosssection are ～0.1 – 0.6 ion gyroradius.

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Properties and Application of Oil-well Cement Enhanced with a Novel Composite Toughening Agent

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Petroleum Science 2007年第2期4卷 52-59页

作者： Hua sudong Yao xiao College of Materials Science and Engineering Nanjing University of Technology Nanjing Jiangsu 210009 China

Brittle fracture of cement sheath, induced by perforation and stimulation treatments, can cause cross flow of formation fluid and increase casing damage. A novel agent XL was developed for solving the problem. Experimental results showed that the toughness of the set cement containing XL was improved remarkably. The engineering properties of the slurry containing XL, drag reducer USZ （0.2% BWOC）, filtrate loss additive F 17B （1.2% BWOC） and crystalloid expanding agent F17A （3% BWOC） could meet technical requirements of cementing operation. After perforation, good quality cement sheath enhanced with XL was observed by CBL/VDL logs in a deep well.

关键词： Oil-well cement cementing cement sheath set cement fiber

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优化开关序列的PWM整流器模型预测控制策略

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电工技术学报 2022年第14期37卷 3665-3675,3700页

作者：肖蕙蕙魏苏东郭强李山兰紫君重庆理工大学重庆市能源互联网工程技术研究中心重庆400054

有限集模型预测控制(FCS-MPC)策略通过在一个采样周期内对有限开关状态遍历寻优,得到当前周期的最优开关状态作用于系统。但由于开关频率不固定,造成系统谐波频谱分散,增加了滤波器设计难度。该文以三相电压源型PWM整流器为研究对象,在... 详细信息

有限集模型预测控制(FCS-MPC)策略通过在一个采样周期内对有限开关状态遍历寻优,得到当前周期的最优开关状态作用于系统。但由于开关频率不固定,造成系统谐波频谱分散,增加了滤波器设计难度。该文以三相电压源型PWM整流器为研究对象,在分析模型预测控制原理的基础上,提出一种基于多矢量合成的优化开关序列模型预测控制(OSS-MPC)策略,在保证系统控制精度的同时,针对有限集模型预测控制策略系统计算量大、开关频率不固定的问题提出改进,通过对有限控制集优化,减小系统计算量;以多矢量合成为基础,通过开关序列重新排列解决开关频率不固定造成的网侧电流频谱分布不均问题。为验证所提出方法的可行性,进行仿真实验并搭建测试样机,在与有限集模型预测控制策略对比的基础上,增加与现有改进策略空间矢量调制模型预测控制(SVM-MPC)的对比实验,进一步验证该文所提策略的有效性与优越性。

关键词： PWM 整流器模型预测控制多矢量合成有限控制集开关序列

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高韧性油井固井材料的性能与应用(英文)

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硅酸盐学报 2007年第6期35卷 786-790页

作者：华苏东姚晓南京工业大学材料科学与工程学院南京210009

针对射孔和增产措施使油井水泥环产生脆性破坏,带来层间流体窜流和套损率上升等难题,开发了一种新型增韧剂HD[合成橡胶粉H的质量分数(下同)w=5.5%;特种化纤D的w=0.2%]。评价了掺HD水泥石的力学性能和微观结构及水泥浆的工程性能。结果表... 详细信息

针对射孔和增产措施使油井水泥环产生脆性破坏,带来层间流体窜流和套损率上升等难题,开发了一种新型增韧剂HD[合成橡胶粉H的质量分数(下同)w=5.5%;特种化纤D的w=0.2%]。评价了掺HD水泥石的力学性能和微观结构及水泥浆的工程性能。结果表明:掺HD油井水泥石的韧性和弹性均被显著提高,抗冲击功提高了198%～222%,Young模量降低了38%～40%;掺HD(w=5.7%),减阻剂USZ(w=0.2%),降滤失剂F17B(w=1.2%)和晶体膨胀剂F17A(w=3%)水泥浆综合性能满足固井施工的基本要求。对不同水泥环中应力波传播速率的计算和模拟射孔实验表明:水泥石弹性模量的降低有利于韧性的提高。

关键词：油井水泥韧性抗冲击功纤维掺量固井

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