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The secular variation of inner zone high energy proton environment in the SAA

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Science China Earth Sciences 2005年第12期48卷 2123-2130页

作者： XIE Lun pu zuyin JIAO Weixin FU suiyan Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China Department of Geophysics Peking University Beijing 100871 China

A long-term variation of the inner zone high-energy proton environment at low orbits was investigated by DSTM using the adiabatic approximation of charge particle motion with NASA standard radiation models as reference states. The DST results show that over the past three decades the fluxes of high-energy protons at ～1000 km in the South Atlantic Anomaly (SAA) noticeably increased, the center region of proton SAA apparently moved westward and expanded. Calculations of the L-shell averaged lifetime of high-energy protons indicate that the DST pro-vides a reasonable means for estimation of the secular variation of inner zone proton environ-ment.

关键词： DSTM, radiation belt, SAA, drift shell, secular variation.

Roles of initial current carrier in the distribution of field-aligned current in 3-D Hall MHD simulations

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Science China(Technological Sciences) 2008年第3期51卷 323-336页

作者： ZHANG XianGuo pu zuyin MA ZhiWei ZHOU XuZhi Institute of Space Physics and Applied Technology School of Earth and Space SciencePeking UniversityBeijing 100871China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China Institute of Fusion Theory and Simulation School of ScienceZhejiang UniversityHangzhou 310027China

A three-dimensional (3-D) Hall MHD simulation is carried out to study the roles of initial current carrier in the topology of magnetic field, the generation and distribu- tion of field aligned currents (FACs), and the appearance of Alfvén waves. Consid- ering the contribution of ions to the initial current, the topology of the obtained magnetic field turns to be more complex. In some cases, it is found that not only the traditional By quadrupole structure but also a reversal By quadrupole structure appears in the simulation box. This can explain the observational features near the diffusion region, which are inconsistent with the Hall MHD theory with the total ini- tial current carried by electrons. Several other interesting features are also emerged. First, motions of electrons and ions are decoupled from each other in the small plasma region (Hall effect region) with a scale less than or comparable with the ion inertial length or ion skin depth di=c/ωp. In the non-Hall effect region, the global magnetic structure is shifted in +y direction under the influence of ions with initial y directional motion. However, in the Hall effect region, magnetic field lines are bent in ?y direction, mainly controlled by the motion of electrons, then By is generated. Second, FACs emerge as a result of the appearance of By. Compared with the prior Hall MHD simulation results, the generated FACs shift in +y direction, and hence the dawn-dusk symmetry is broken. Third, the Walén relation in our simulations is consistent with the Walén relation in Hall plasma, thus the presence of Alfvén wave is confirmed.

关键词： collisionless magnetic reconnection Hall MHD simulation field aligned current (FAC) Alfvén wave Hall effects

Non-storm erosion of MeV electron outer radiation belt down to L^(*)<4.0 associated with successive enhancements of solar wind density

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Earth and Planetary Physics 2021年第6期5卷 581-591页

作者： Ying Xiong Lun Xie SuiYan Fu BinBin Ni zuyin pu School of Earth and Space Science Peking UniversityBeijing 100871China Department of Earth and Space Sciences Southern University of Science and TechnologyShenzhen 518055China Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China

We report an unusual non-storm erosion event of outer zone MeV electron distribution during three successive solar wind number density enhancements(SWDEs)on November 27-30,*** of MeV electrons and energy-dependent narrowing of electron pitch angle distributions(PAD)first developed at L^(*)=5.5 and then moved down to L^(*)4 during SWDE1 are mainly due to outward radial *** during SWDE2&3,scattering loss due to EMIC waves is dominant at 4

关键词： solar wind density enhancement outer radiation belt MeV electrons outward radial diffusion EMIC wave scattering loss

Downward current electron beams observed at the dipolarization front

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Chinese Science Bulletin 2013年第8期58卷 913-919页

作者： ZHENG Hao FU SuiYan ZONG QuiGang pu zuyin School of Earth and Space Sciences Peking University

The strong field-aligned pitch angle distribution of electrons is observed right at the dipolarization front (DF) before the arriving of a high speed flow when the four Cluster satellites are traveling in the magnetotail around 15 R E on July 22, 2001. The increased electron fluxes only last for a short time period at the DF, corresponding to just a few bouncing periods for 1 keV electrons. The field-aligned current contributed by these electrons agrees well with that calculated by the magnetic field observations by four satellites at the front. These electron streams are found in the energy range of 0.2-2 keV, peak around 1 keV. It is suggested that these downward current electrons may be originated near the aurora region by some kinds of potential structure. The occurrence of these electrons implies that the formation of the dipolarization front and the associated field-aligned current play an important role in the magnetosphere-ionosphere coupling.

关键词：场向电流电子束极化 Cluster 电离层耦合磁场观测能量范围高速流

Recent progresses in theoretical studies and satellite observations for collisionless magnetic reconnection

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Chinese Science Bulletin 2012年第12期57卷 1369-1374页

作者： WANG XiaoGang XIAO ChiJie pu zuyin WANG JiaQi School of Physics and State Key Laboratory of Nuclear Physics ＆ Technology Peking University Beijing 100871 China School of Earth and Space Sciences Peking University Beijing 100871 China College of Physical Science and Technology Sichuan University Chengdu 610064 China

As an essential mechanism in large scale fast magnetic energy releases and field reconfigurations processes in space,astrophysical, and laboratory plasmas,magnetic reconnection,particularly collisionless magnetic reconnection,has been studied for more than 65 *** progresses have been achieved in recent years and basic features of the process have been well understood,largely due to more and more satellite observation data available in the last ***,a few outstanding issues are still remained *** in the paper review the development of collisionless magnetic reconnection studies and major achievements in recent years,and also briefly discuss the open questions remained to be answered in studies of collisionless magnetic reconnection.

关键词：卫星观测数据磁场重联碰撞天体物理学配置过程空间领域能量释放等离子体

Recent Progresses of Magnetospheric Physics in China:2010—2011

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空间科学学报 2012年第5期32卷 647-664页

作者： CAO Jinbin LIU Zhenxing pu zuyin Space Science Institute.Beihano University Beijing 100191 State Key Laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of SciencesBeijing 100190 School of Earth and Space Sciences Peking UniversityBeijing 100871

In the past two years,many progresses are made in magnetospheric physics by using either the data of Double Star Program,Cluster and THEMIS missions,or by computer simulations. This paper briefly reviews these works based on papers selected from the 80 publications from April 2010 to April *** subjects covered various sub-branches of magnetospheric physics,including geomagnetic storm,magnetospheric substorm,etc.

关键词： Magnetospheric physics Geomagnetic storm Substorm Radiation belt Magnetic field reconnection

Scientific Progress of Combined Exploration DSP and Cluster:2008-2010

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空间科学学报 2010年第5期30卷 404-421页

作者： Liu Zhenxing Cao Jinbin pu zuyin State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 School of Astronautics Beihang University School of Earth and Space Sciences Peking University

The combined observations of Double Star and Cluster missions allow for,for the first time,six-point measurements of the main plasma parameters in the key scientific regions of the near-Earth *** the past two years,a great number of works were made based on the data from DSP and Cluster missions,advancing remarkably the research of magnetospheric physics in *** paper briefly reviews these important scientific results based on 51 selected publications.

关键词： DSP 联合勘探科技进步 Cluster 集群等离子体参数科学成果组合观测值

Magnetospheric Physics in China:2008-2010

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空间科学学报 2010年第5期30卷 445-455页

作者： Cao Jinbin Liu Zhenxing pu zuyin School of Astronautics Beihang University Beijing 100191 State Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences School of Earth and Space Sciences Peking University

In the past two years,most of the works on magnetospheric physics were made by using the data of Double Star Program and Cluster *** some works were still conducted by computer simulation or using the data from other space missions and ground geomagnetic *** paper briefly review these previous works based on papers selected from the 28 publications from April 2008 to April *** subjects covered various sub-branches of magnetospheric physics,including geomagnetic storm,magnetospheric substorm and etc.

关键词：磁层亚暴物理学 Cluster 中国计算机模拟双星计划观测数据飞行任务

Ultra low frequency waves observed by Double Star TC-1 in the plasmasphere boundary layer

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Science China(Technological Sciences) 2008年第10期51卷 1685-1694页

作者： XIE Lun ZHANG XiaoJia pu zuyin WANG YongFu FU SuiYan ZONG QiuGang Department of Geophysics Peking UniversityBeijing 100871China

The characteristic and properties of ULF waves in the plasmasphere boundary layer during two very quiet periods are present. The ULF waves were detected by Double Star TC-1 when the spacecraft passed through the plasmasphere in an outbound and inbound trajectories, respectively. A clear association between the ULF waves and periodic variations of energetic ions fluxes was observed. The ob-servations showed that the wave frequency was higher inside the plasmasphere than outside. The mechanism generating these ULF waves and possible diagnos-ing of the "classical plasmapause" location with the ULF wave were discussed.

关键词： ULF wave PBL plasmasphere plasmapause DSP TC-1