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Effects of Martian crustal magnetic field on its ionosphere

Science china(Technological Sciences) 2010年第6期53卷 1717-1724页

作者： ZOU Hong,CHEN HongFei,YU Ning,SHI WeiHong,YU XiangQian,ZOU JiQing & ZHONG WeiYing institute of space physics and applied technology,peking university,beijing 100871,china institute of space physics and applied technology Peking University Beijing China

The effect of the Martian crustal magnetic field is one of the hot topics of the study of Martian *** studies on this topic are summarized in this *** data of the Martian ionosphere were resulted from radio occultation *** to the observations,the electron density scale height and the peak electron density of the Martian ionosphere are influenced by its crustal magnetic *** strong horizontal magnetic field prevents the vertical diffusion of the plasma and makes the electron density scale height in the topside ionosphere close to that in the photo equilibrium *** the cusp-like regions with strong vertical magnetic field,the enhanced vertical diffusion leads to a larger electron density scale height in the diffusion equilibrium *** observation of radio occultation experiment onboard Mars Global Surveyor (MGS) showed that the averaged peak electron density observed in the southern hemisphere with strong crustal magnetic field was slightly larger than that in the northern hemisphere with weak crustal magnetic *** Mars advanced radar for subsurface and ionosphere sounding (MARSIS) onboard Mars Express (MEX) was the first topside sounder to be used to observe Martian *** MARSIS results confirmed that the enhancement of the peak electron density occurred in cusp-like regions with open field lines,and the amount of the enhancement was much larger than that observed by the radio occultation *** are two possible mechanisms for the peak electron density enhancement in the cusp-like crustal magnetic field regions:One is the precipitation of the energetic particles and the other is the heating by the waves excited by plasma ***'s difficult to determine which one is the key mechanism for the peak electron density *** on these studies,several interesting problems on the Martian ionosphere and plasma environment are presented.

关键词： Mars exploration Martian crustal megnetic field Martian ionosphere energetic particles detection plasma wave detection

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Propagation of interplanetary shock excited ultra low frequency (ULF) waves in magnetosphere-ionosphere-atmosphere——Multi-spacecraft “Cluster” and ground-based magnetometer observations

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Science china(Technological Sciences) 2010年第9期53卷 2528-2534页

作者： WANG ChengRui1,2,ZONG QiuGang1,3 & WANG YongFu1 1 institute of space physics and applied technology,peking university,beijing 100871,china 2 Sate Key Laboratory of space Weather,Chinese Academy of Sciences,beijing 100190,china 3 Center for Atmospheric Research,600 Suffolk Street,university of Massachusetts Lowell,MA 01854,USA institute of space physics and applied technology Peking University Beijing China Sate Key Laboratory of space Weather Chinese Academy of Sciences Beijing China Center for Atmospheric Research University of Massachusetts Lowell USA

The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward *** paper quantitatively analyzes the propagation process of the ULF wave triggered by the interplanetary shock propagating from inner magnetosphere equatorial plane along magnetic field lines to the top of the ionosphere and below ionosphere propagating process and establishes a relatively complete magnetosphere-ionosphere-atmosphere propagation model which can be used to study the relationship between the amplitude of the ULF waves triggered by the interplanetary shock wave in magnetospheric space and the magnetic effect caused by the ULF *** a comparison with recent observations,we found that: in the event during November 7,2004 that an interplanetary shock wave interacted with the magnetosphere,Cluster satellites observed that electric field fluctuations and the band-pass filtered result of ground stations meridional component had similar *** with the geomagnetic measurement near the footprints,we found that the electric field disturbance in the magnetosphere spread along the ground magnetic field lines in the form of the ULF waves and changed into geomagnetic *** result reveals that the ULF wave is in contact with the ground geomagnetic *** ULF waves couple with ionized components in ionosphere and spread to the ground in the form of electromagnetic *** this research,we believe that the magnetosphere,ionosphere and ground magnetic effects caused by interplanetary shock wave are the same physical phenomena responding in different *** on the overall consideration of entire electromagnetic response to the interplanetary shock wave,we found that the correlation between CLUSTER multi-satellite observation and geomagnetic station observation is due to the ULF wave propagated in magnetosphere-ionosphere-atmosphere system,and we quantitatively interpreted this response process

关键词： ultra low frequency (ULF) wave magnetic storm ionosphere IRI model interplanetary shock

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Latest progress on interactions between VLF/ELF waves and energetic electrons in the inner magnetosphere

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Science china Earth Sciences 2010年第3期53卷 317-326页

作者： XIAO FuLiang1,2, ZONG QiuGang3, SU ZhenPeng4, TIAN Tian3 & ZHENG HuiNan4 1 School of physics and Electronic Sciences, Changsha university of Science and technology, Changsha 410004, china 2 State Key Laboratory of space Weather, Chinese Academy of Sciences, beijing 100190, china 3.institute of space physics and applied technology, peking university, beijing 100871, china 4 CAS Key Lab for Basic Plasma Science, School of Earth and space Sciences, university of Science and technology of china, Hefei 230026, china School of physics and Electronic Sciences Changsha University of Science and Technology Changsha China State Key Laboratory of space Weather Chinese Academy of Sciences Beijing China institute of space physics and applied technology Peking University Beijing China CAS Key Lab for Basic Plasma Science School of Earth and Space Sciences University of Science and Technology of China Hefei China

Interactions between very/extremely low frequency (VLF/ELF) waves and energetic electrons play a fundamental role in dynamics occurring in the inner magnetosphere. Here, we briefly discuss global properties of VLF/ELF waves, along with the variability of the electron radiation belts associated with wave-particle interactions and radial diffusion. We provide cases of electron loss and acceleration as a result of wave-particle interactions primarily due to such waves, and particularly some preliminary results of 3D evolution of phase space density from our currently developing 3D code. We comment on the existing mechanisms responsible for acceleration and loss, and identify several critical issues that need to be addressed. We review latest progress and suggest open questions for future investigation.

关键词： wave-particle interaction VLF/ELF waves energetic electrons acceleration and loss inner magnetosphere

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New progress in the principle of nonequilibrium statistical physics

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Chinese Science Bulletin 2001年第6期46卷 448-454页

作者： XING XiusanDepartment of applied physics, beijing institute of technology, beijing 100081, china Department of applied physics Beijing Institute of Technology Beijing China

In recent years, a new fundamental equation of nonequilibrium statistical physics was proposed in place of the Liouville equation. That is the anomalous Langevin equation in (?) space or its equivalent Liouville diffusion equation of time-reversal asymmetry. This equation reflects that the form of motion of particles in statistical thermody-namic systems has the drift-diffusion duality and the law of motion of statistical thermodynamics is stochastic in essence, but does not obey the Newton equation of motion, though it is also constrained by dynamics. The stochastic diffusion of the particles is the microscopic origin of macroscopic irre-versibility. Starting from this equation, the BBGKY diffusion equation hierarchy was presented, the hydrodynamic equations, such as the generalized Navier-Stokes equation, the mass drift-diffusion equation and the thermal conductivity equation have been derived succinctly. The unified description of all three level equations of microscopic, kinetic and hydrodynamic

关键词： anomalous Langevin equation in space drift-diffusion duality stochastic law nonequilibrium entropy evolution equation entropy diffusion.

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Effect of upward ion on field-aligned currents in the near-earth magnetotail

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Science china(physics,Mechanics & Astronomy) 2007年第5期50卷 673-680页

作者： ZHANG LingQian1, LIU ZhenXing1, MA ZhiWei2, SHEN Chao1, ZHOU XuZhi3 & ZHANG XianGuo3 1 Center for space and applied Research, Chinese Academy of Sciences, beijing 100080, china 2 institute of Plasma physics, Chinese Academy of Sciences, Hefei 230031, china 3 School of Earth and space Science, peking university, beijing 100871, china Center for space and applied Research Chinese Academy of Sciences Beijing China institute of Plasma physics Chinese Academy of Sciences Hefei China School of Earth and space Science Peking University Beijing China

A 3-dimensional resistive MHD simulation was carried out to study the effect of the upward ions on the field-aligned currents (FACs) in the near-earth magnetotail. The simulation results show that the up-flow ions originating from the nightside auroral oval would drift into the center plasma sheet along the magnetic field lines in the plasma sheet boundary, and have an important effect on the field-aligned currents. The main conclusions include that: 1) the upward-ions mainly affect the field- aligned currents in the near-earth magnetotail (inside 15 Re); 2) the generated FACs in the near-earth region have two types, i.e., Region 1 FAC in the high-latitude and Region 2 FAC in the low-latitude; 3) FACs increase with the enhancement of the upward ion flux; 4) with the same flux of the upward ions, FACs enhance with the increase of the velocity of the up-flow ions; 5) the intensification of FACs is also closely related with the latitude of the upward ions, and the ions from the closed field line region generate larger FACs; 6) the generation of FACs is closely related with By created by the upward ions.

关键词： up-flow ions, near-earth magnetotail, field-aligned current

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New numerical algorithms in SUPER CE/SE and their applications in explosion mechanics

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 237-243页

作者： WANG Gang1,2,WANG JingTao1 & LIU KaiXin1,3 1 LTCS and College of Engineering,peking university,beijing 100871,china 2 LHD,institute of Mechanics,Chinese Academy of Sciences,beijing 100190,china 3 Center for applied physics and technology,peking university,beijing 100871,china LTCS and College of Engineering Peking University Beijing China LHD Institute of Mechanics Chinese Academy of Sciences Beijing China Center for applied physics and technology Peking University Beijing China

The new numerical algorithms in SUPER/CESE and their applications in explosion mechanics are studied. The researched al-gorithms and models include an improved CE/SE (space-time Conservation Element and Solution Element) method,a local hybrid particle level set method,three chemical reaction models and a two-fluid model. Problems of shock wave reflection over wedges,explosive welding,cellular structure of gaseous detonations and two-phase detonations in the gas-droplet system are simulated by using the above-mentioned algorithms and models. The numerical results reveal that the adopted algorithms have many advantages such as high numerical accuracy,wide application field and good compatibility. The numerical algo-rithms presented in this paper may be applied to the numerical research of explosion mechanics.

关键词： new algorithm SUPER CE/SE numerical simulation explosion mechanics

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Numerical and experimental investigation of the fracture behavior of shock loaded alumina

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Science china(physics,Mechanics & Astronomy) 2010年第2期53卷 244-252页

作者： REN HuiLan1,SHU XueFeng2 & LI Ping3 1 State Key Laboratory of Explosion Science and technology,beijing institute of technology,beijing 100081,china 2 institute of applied Mechanics and Biomedical Engineering,Taiyuan university of technology,Taiyuan 030024,china 3 Labroratory for Shock Wave and Detonation physics Research,institute of Fluid physics,CAEP,Mianyang 610059,china State Key Laboratory of Explosion Science and technology Beijing Institute of Technology Beijing China institute of applied Mechanics and Biomedical Engineering Taiyuan University of Technology Taiyuan China Labroratory for Shock Wave and Detonation physics Research Institute of Fluid Physics CAEP Mianyang China

Plate impact expeiments are conducted to investigate the dynamic behavior of alumina by using one stage light gas gun. A ve-locity interferometer system for reflectors (VISAR) is used to obtain Hugoniot elastic limit and the free surface velocity profile,which consists of an elastic wave followed immediately by a dispersive inelastic wave. The stress histories under different impact velocities are measured by in-material manganin gauges. Based on the experimental data a Hugoniot curve is fitted,which shows the compressive characteristics that alumina changes typically from elastic to "plastic" ,and under higher pressure it will be transferred to similar-fluid state. The turning point of the Hugoniot curve from a high pressure region to a low pressure region is about 11.4 GPa. The fracture process of alumina is simulated by way of finite element code. After the analysis of the fracture mechanism,the numerical results show an important role played by the nucleation and the growth of the cracks in the macro-scopic fracture of the alumina target. The numerical predictions of stress histories are compared with the experimental results,which indicates consistency between them.

关键词： plate impact experiment hugoniot curve fracture characteristics numerical simulation

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A MULTIGRID METHOD FOR NONLINEAR PARABOLIC PROBLEMS

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Journal of Computational Mathematics 1996年第4期14卷 363-382页

作者： x.J. Yu(Laborutory of Computational physics, institute of applied physics and ComputationalMathematics, beijing, china) Laboratory of Computational physics Institute of Applied Physics and Computational Mathematics Beijing China

The multigrid algorithm in [13] is developed for solving nonlinear parabolic equations arising from the finite element discretization. The computational cost of the algorithm is approximate O(NkN) where N-k is the dim... 详细信息

关键词： Th Math A MULTIGRID METHOD FOR NONLINEAR PARABOLIC PROBLEMS UC

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An atomistic simulation of site preference and vibrational properties of UMxAl12-x (M = Fe, Co, Ni, Cr and Mn) and UMxAl12-xHx

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Progress in Natural Science:Materials International 2009年第8期19卷 983-989页

作者： Huijun Tian a,b, Ping Qian a, Jiang Shen a, Nanxian Chen a,c a institute of applied physics, beijing university of Science and technology, beijing 100083, china b School of physics, beijing university of Chemical technology, beijing 100029, china c Department of physics, Tsinghua university, beijing 100084, china institute of applied physics Beijing University of Science and Technology Beijing 100083 China School of physics Beijing University of Chemical Technology Beijing 100029 China Department of physics Tsinghua University Beijing 100084 China

A series of lattice inversion pair potentials are used to evaluate the phase stability and site preference for uranium intermetallics UMxAl12 x (M = Fe, Co, Ni, Cr and Mn) and their related hydrides. Calculated results show that Fe, Co, Ni, Cr or Mn atoms preferentially substitute Al at the 8f site. Interstitial H atoms only occupy 2b interstitial sites in UMxAl12 x. Calculated lattice constants are found to agree with a report in the literature. Elastic constants and bulk modulus of UMxAl12 x and UMxAl12 xH were also investigated. In particular, the phonon densities of states (DOS) of these actinide compounds were evaluated for the first time.

关键词： Interatomic potentials Site preference Lattice vibration

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FORMATION OF HEXAGONAL Co_(2—3)C IN Co BY CARBON ION IMPLANTATION

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Acta Metallurgica Sinica(English Letters) 1992年第2期5卷 137-140页

作者： WANG Jian WU Xingfang CHEN Xunping CAI Jun university of Science and technology beijing,beijing,china LIU Baixin Tsinghua university,beijing,china FANG Zhengzhi beijing institute of space physics,Academia Sinica,beijing,china Univ of Science and technology Beijing Beijing China

Co thin films were subjected to 50 keV carbon ion *** the dose of 2.5× 10^(17)/cm^2,a hexagonal Co-carbide phase was observed for the first *** lattice con- stants from electron diffraction are a=0.2685 nm and c=0.4335 *** phase does not dis- appear until the dose of 9×10^(17)/cm^*** spectra showed that the stoichiometry was Co_(2-3)*** behavior of the ferromagnetic carbides along the descending sequence of Ni-Fe-Co by Fermi energy of solids was ***,based on the kinetic con- dition of phase transformation and the band theory of solids,a possible explanation about the difference of the results of ion-metallurgy and thermal metallurgy was proposed.

关键词： ion implantation phase Fermi energy Co Co_(2_3)C

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