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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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Scalings for the Alfvén-cyclotron instability in a bi-kappa plasma

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地球与行星物理:英文版 2023年第6期7卷 631-639页

作者： YueQun Lou Xing Cao MingYu Wu BinBin Ni tielong zhang Shenzhen Key Laboratory of Numerical Prediction for Space Storm Institute of Space Science and Applied TechnologyHarbin Institute of TechnologyShenzhen 518055China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China Chinese Academy of Sciences Center for Excellence in Comparative Planetology Hefei 230026China Space Research Institute Austrian Academy of SciencesGraz 8042Austria

The particle velocity distribution in space plasma usually exhibits a non-Maxwellian high-energy tail that can be well modeled by kappa distributions.In this study,we focus on the growth rates of the Alfvén-cyclotron instability driven by ion temperature anisotropy in a kappa plasma.By solving the kinetic linear dispersion equation,we explore the sensitivity of growth rates to the spectral indexκof a bi-kappa distribution under different plasma conditions,including a variety of plasma beta β_(hp) and temperature anisotropy A_(hp) values of hot protons.Furthermore,a concise,analytic scaling formula is derived that relates the dimensionless maximum growth rate to three independent variables:the spectral index and the plasma beta and temperature anisotropy of hot protons.Our results show that as theκ-value increases,the instability bandwidth narrows and the maximum growth rate increases significantly.For higherβ_(hp)and A_(hp)′the maximum instability undergoes a sharp increase as well.When our fits of dimensionless maximum growth rates are compared with solutions to kinetic linear dispersion theory,the results generally exhibit good agreement between them.Especially under the circumstances of largeκ-values and highβ_(hp)and A_(hp)′the scalings of maximum growth rates primarily accurately model the numerical solutions.Our analytic expressions can readily be used in large-scale models of the Earth’s magnetosphere to understand wave generation due to the Alfvén-cyclotron instability.

关键词： Alfvén-cyclotron instability kappa distribution kinetic linear dispersion theory scaling formula

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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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Theoretical Study on Ion Escape in Martian Atmosphere

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Chinese Physics Letters 2007年第1期24卷 298-301页

作者：史建魁刘振兴 Klaus TORKAR tielong zhang State Key Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 Space Research Institute Austrian Academy of Sciences A-8042 Graz Austria

基于火星的磁性的时刻逐渐地正在减少从的观察对礼品古老，我们沿着与不同假定火星的磁性的时刻在火星的尾巴逃离流动的磁场线和离子调查 O + 离子流动分发。结果证明沿着磁场线的 O + 离子流动从火星与距离减少；如果磁性的时刻更大，... 详细信息

基于火星的磁性的时刻逐渐地正在减少从的观察对礼品古老，我们沿着与不同假定火星的磁性的时刻在火星的尾巴逃离流动的磁场线和离子调查 O + 离子流动分发。结果证明沿着磁场线的 O + 离子流动从火星与距离减少；如果磁性的时刻更大，沿着领域线的离子流动更快速减少；越大磁性的时刻，越 smaller 在火星的尾巴逃离流动的离子。逃离流动的离子在火星的尾巴取决于 Z 坐标。与磁性的时刻的减少，在火星的尾巴逃离流动的离子增加。结果为从火星表面学习水损失是重要的。

关键词：离子逃避理论学习火星大气圈

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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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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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新能源检测技术在电力系统中的应用及性能评估

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电力系统装备 2024年第2期 91-93页

作者：张铁龙北京京能国际控股有限公司西北分公司宁夏银川750411

随着新能源在电力系统中应用的增加,对新能源的准确监测和控制成为了一个重要的技术挑战。文章研究了新能源检测技术在电力系统中的应用与性能分析。概述了新能源的概念和分类,介绍了传统电力系统架构与新能源集成的需求,详细阐述了新... 详细信息

随着新能源在电力系统中应用的增加,对新能源的准确监测和控制成为了一个重要的技术挑战。文章研究了新能源检测技术在电力系统中的应用与性能分析。概述了新能源的概念和分类,介绍了传统电力系统架构与新能源集成的需求,详细阐述了新能源检测技术的基本原理。讨论了新能源检测技术在新能源发电量监测、新能源负荷预测和新能源功率平衡控制方面的应用,并对新能源检测技术的性能进行了评估,以期为相关人员提供参考。

关键词：新能源电力系统检测技术

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Ablation of Venusian oxygen ions by unshocked solar wind

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Science Bulletin 2017年第24期62卷 1669-1672页

作者： Yong Wei Markus Fraenz Edward Dubinin Weixing Wan tielong zhang Zhaojin Rong Lihui Chai Jun Zhong Rixiang Zhu Yoshifumi Futaana Stas Barabash Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Max-Planck-lnstitute for Solar System Research Goettingen 37077 Germany Space Research Institute Austrian Academy of Sdences Graz 8042 Austria Swedish Institute of Space Physics Kiruna SE-981 28 Sweden College of Earth Sciences University of Chinese Academy of Sciences Beijing 100049 China Institutions of Earth Science Chinese Academy of Sciences BeUing 100029 China

As an Earth-like planet Venus probably had a primordial dipole field for several million years after formation of the planet.Since this dipole field eventually vanished the ionosphere of Venus has been exposed to the solar wind.The solar wind is shocked near Venus,and then scavenges the ionospheric particles through the magnetosheath and the magnetotail.The escape rate of oxygen ions(O^+)estimated from spacecraft observations over the past several decades has manifested its importance for the evolution of planetary habitability,considering the accumulated effect over the history of Venus.However,all the previous observations were made in the shocked solar wind and/or inside the wake,though some simulations showed that unshocked solar wind can also ablate O^+ions.Here we report Venus Express observations of O^+ions in the unshocked solar wind during the solar minimum.The observations suggest that these O^+ions are accelerated by the unshocked solar wind through pickup processes.The estimated O^+escape rate,2.1×10^(24) ions/s,is comparable to those measured in the shocked solar wind and the wake.This escape rate could result in about 2 cm global water loss over 4.5 billion years.Our results suggest that the atmospheric loss at unmagnetized planets is significantly underestimated by previous observations,and thus we can emphasize the importance of an Earth-like dipole for planetary habitability.

关键词： Venus Ion escape Planetary habitability

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Mars Orbiter magnetometer of China’s First Mars Mission Tianwen-1

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Earth and Planetary Physics 2020年第4期4卷 384-389页

作者： Kai Liu XinJun Hao YiRen Li tielong zhang ZongHao Pan ManMing Chen XiaoWen Hu Xin Li ChengLong Shen YuMing Wang Chinese Academy of Sciences Key Laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Space Research Institute Austrian Academy of SciencesGrazAustria

As one of the seven scientific payloads on board the Tianwen-1 orbiter,the Mars Orbiter Magnetometer(MOMAG)will measure the magnetic fields of and surrounding Mars to study its space environment and the interaction with the solar wind.The instrument consists of two identical triaxial fluxgate magnetometer sensors,mounted on a 3.19 meter-long boom with a seperation of about 90 cm.The dual-magnetometers configuration will help eliminate the magnetic field interference generated by the spacecraft platform and payloads.The sensors are controlled by an electric box mounted inside the orbiter.Each magnetometer measures the ambient vector magnetic field over a wide dynamic range(to 10,000 nT per axis)with a resolution of 1.19 pT.Both magnetometers sample the ambient magnetic field at an intrinsic frequency of 128 Hz,but will operate in a model with alternating frequency between 1 and 32 Hz to meet telemetry allocations.

关键词： Mars magnetic field magnetometer Tianwen-1 spaceflight instrumentation

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一种高磁洁净卫星磁性建模与仿真计算方法

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航天器环境工程 2024年第3期41卷 296-300页

作者：孟立飞陈金刚肖琦张琼予邓佳欣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 北京卫星环境工程研究所北京100094 奥地利科学院空间研究所格拉茨A-8042

卫星的磁洁净度是影响空间磁场测量精度的关键因素之一。为了在设计阶段预估“张衡一号”卫星的磁洁净度,文章提出一种基于单机多磁偶极子模型的卫星磁性建模与仿真计算方法:首先通过单机磁场测量数据构建单机多磁偶极子模型;然后根据... 详细信息

卫星的磁洁净度是影响空间磁场测量精度的关键因素之一。为了在设计阶段预估“张衡一号”卫星的磁洁净度,文章提出一种基于单机多磁偶极子模型的卫星磁性建模与仿真计算方法:首先通过单机磁场测量数据构建单机多磁偶极子模型;然后根据单机的安装位置和方向组合成整星磁性模型;进而仿真计算卫星绝对磁场校准装置位置处的磁场。整星磁试验验证结果表明,该仿真方法可信有效,可应用于同类高磁洁净卫星的磁性建模与仿真计算。

关键词： “张衡一号”卫星磁性建模磁性仿真多磁偶极子模型空间磁场探测

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