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Deformations at Earth’s dayside magnetopause during quasi-radial IMF conditions:Global kinetic simulations and Soft X-ray Imaging

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Earth and Planetary Physics 2024年第1期8卷 59-69页

作者： ZhongWei Yang Riku Jarvinen XiaoCheng Guo TianRan Sun Dimitra koutroumpa george k.parks Can Huang BinBin Tang QuanMing Lu Chi Wang State key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Finnish Meteorological Institute FI-00101 HelsinkiFinland LATMOS/IPSL CNRSUVSQ UniversitéParis-SaclaySorbonne UniversitéGuyancourt78280France Space Sciences Laboratory University of CaliforniaBerkeleyCalifornia 94720USA CAS Engineering Laboratory for Deep Resources Equipment and Technology Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029 China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China

The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Earth's magnetosphere to the solar wind(SW)impact via simultaneous in situ magnetosheath plasma and magnetic field measurements,X-Ray images of the magnetosheath and magnetic cusps,and UV images of global auroral *** deformations associated with magnetosheath high speed jets(HSJs)under a quasi-parallel interplanetary magnetic field condition are studied using a threedimensional(3-D)global hybrid *** X-ray intensity calculated based on both physical quantities of solar wind proton and oxygen ions is *** obtain key findings concerning deformations at the magnetopause:(1)Magnetopause deformations are highly coherent with the magnetosheath HSJs generated at the quasi-parallel region of the bow shock,(2)X-ray intensities estimated using solar wind h+and self-consistentO7+ions are consistent with each other,(3)Visual spacecraft are employed to check the discrimination ability for capturing magnetopause deformations on Lunar and polar orbits,*** SMILE spacecraft on the polar orbit could be expected to provide opportunities for capturing the global geometry of the magnetopause in the equatorial plane.A striking point is that SMILE has the potential to capture small-scale magnetopause deformations and magnetosheath transients,such as HSJs,at medium altitudes on its *** results also demonstrate that a lunar based imager(e.g.,Lunar Environment heliospheric X-ray Imager,LEXI)is expected to observe a localized brightening of the magnetosheath during HSJ events in the meridian *** preliminary results might contribute to the pre-studies for the SMILE and LEXI missions by providing qualitative and quantitative soft X-ray estimates of dayside kinetic processes.

关键词： collisionless shock SMILE mission foreshock

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Magnetotail High-Speed Plasma Flows at Geomagnetically Quiet Times: Relation to the Magnetic Reconnection and Auroral Activation

Magnetotail High-Speed Plasma Flows at Geomagnetically Quiet...

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第十四届全国日地空间物理学术研讨会

作者：野和田基晴 george k.parks 傅綏燕濮祖蔭 Vassilis Angelopoulos Charles W.Carlson Hans-Ulrich Auster Institute of Space Physics and Applied Technology School of Earth and Space Sciences Peking University Beijing Haidian District100871 People Republic Of China Space Science Laboratory University of California Berkeley California 94720-7450 U.S.A Institute of Geophysics and Planetary Physics University of California Los Angeles California 90095 U.S.A Institut für Geophysik und Extraterrestrische Physik Technische Universitt Braunschweig 3 D-38106 Germany

It has been widely accepted that a major mechanism for generating the high-speed plasma flows （HSPFs） observed in the magnetotail is the magnetic reconnection. Furthermore, these magnetotail HSPFs are observed at both geomagnetically quiet and active times. However, it has been open question and controversial whether the magnetic reconnection is main mechanism to produce even magnetotail HSPFs observed at geomagnetically quiet times, and how the relationship between the HSPFs and the auroral activation is. In this study, we focused on the 4 magnetotail HSPF events observed by THEMIS. The main characteristics of these HSPF events are shown as follows;1) the value of the GSM-X component for the plasma velocity （|Vx|） was higher than 300 km/s 2) the velocity perpendicular to the local magnetic field （|V⊥|） ranged between about 200 km/s and 500 km/s 3) these high-speed plasma flows are observed during which the AL and AU indices were lower than 40 nT and the range of the kp index was between -1 and 1. Simultaneous all magnetic field components were varying and magnetic field intensity showed the enhancement in almost all events. These results are clearly suggesting that the HSPFs induced some magnetic perturbations, and the magnetic flux was transported and piled up by the HSPFs in the magnetotail even at geomagnetically quiet times. Interestingly, some HSPF events were associated with the Pi 2 waves, but the others were not. Therefore, the magnetic reconnection might not always play a crucial role for producing the HSPFs at geomagnetically quiet times. Furthermore, the striking auroral activation was not observed in all events, indicating that the HSPFs at geomagnetically quiet times can occur in association with not only "substorm" but also "substorm-like phenomena", such as pseudo-substorm.

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Altitude of the upper boundary of AAR based on observations of ion beams in inverted-V structures:A case study

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Science China Earth Sciences 2016年第7期59卷 1489-1497页

作者： CUI YanBo FU SuiYan ZONG QiuGang XIE Lun SUN WeiJie ZHAO Duo WU Tong george parks School of Earthand Space Sciences Peking University key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences Space Sciences Laboratory University of CaliforniaBerkeley

Outflowing ion beams forming four successive inverted-V structures in the energy-time spectrograms of H+, He+, and O+ were observed at an altitude of 3.4 RE by Cluster satellites travelling above the auroral acceleration region (AAR) in the southern hemisphere on February 14, 2001. Energization by negative U-shaped potential structures in the AAR is believed to be responsible for the formation of these outflowing ion inverted-V structures. Thus, utilizing the different motion properties of the three ion species, the altitude of the upper boundary of the AAR is estimated to be ~11100 km. Moreover, based on multi-satellite observations, each of these U-shaped potential structures involved in this event crosses the latitudinal direction at ~0.4°–1° invariantlatitude (ILAT), moving poleward at an average speed of ~0.2° ILAT per minute, before disappearing at ~71.5° ILAT.

关键词： Outflowing ion beams Inverted-V structure Auroral acceleration region U-shaped potential structure Altitude of upper boundary

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THEMIS observation of a magnetotail current sheet flapping wave

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Chinese Science Bulletin 2014年第2期59卷 154-161页

作者： Weijie Sun Suiyan Fu Quanqi Shi Qiugang Zong Zhonghua Yao Ting Xiao george parks School of Earth and Space Sciences Peking University Shandong Provincial key Laboratory of Optical Astronomy and Solar-Terrestrial Environment School of Space Science and Physics Shandong University at Weihai Space Sciences Laboratory UC Berkeley Berkeley

A flapping wave was observed by THEMIS-B(P1)and THEMIS-C(P2)probes on the dawn side of the magnetotail,while the solar wind was generally *** magnetic activity was quite weak,suggesting that this flapping wave was generated by an internal instability,which normally occurs during magnetic quiet *** analysis shows that the flapping wave was propagating downward with a tail-aligned scale of at least 3.7 R E and did not show much change in shape during its propagation from P1 to *** analysis employed to estimate the time lag between the corresponding half waveforms of P1 and P2 shows that the propagating velocities along the current sheet normal directions were close to each other in the beginning,but increased linearly later *** average wavelength of the flapping wave is approximately 4 R *** analysis suggests that the ballooning type wave model may not be the mechanism for the observed flapping wave,but that the magnetic double-gradient instability model is a more plausible candidate.

关键词：电流片磁尾传播速度不稳定性波动模型相关性分析总体稳定时间延迟

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High-speed flowing plasmas in the Earth’s plasma sheet

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Chinese Science Bulletin 2011年第12期56卷 1182-1187页

作者： FU SuiYan SHI QuanQi WANG Chi parks george ZHENG Ling ZHENG Hao SUN WeiJie School of Earth and Space Sciences Peking University Beijing 100871 China State key Laboratory of Space Weather Chinese Academy of Sciences Beijing 100190 China School of Space Science and Physics Shandong University at Weihai Weihai 264209 China Space Sciences Laboratory UC Berkeley Berkeley CA94720-5200 USA

A research topic of great interest to the space physics community is the observation of plasmas flowing at hundreds of kilometers per second in the Earth’s plasma sheet. Although considerable effort has been made to understand the source of fast-flowing plasmas, many questions remain unanswered about the mechanisms that produce high-speed flows and the effects they have on magnetospheric disturbances, especially their contributions to magnetospheric convection and substorms. In this paper, we discuss briefly the history of high-speed flows and review the proposed mechanisms, signatures of high-speed flows in auroras and their interaction with the background plasma. We then summarize the relationships between high-speed flows and magnetic structures, discuss questions associated with substorms, and finally pose several important scientific questions that need to be addressed.

关键词：等离子体片高速流动地球磁层对流空间物理学等离子体源相互作用科学问题

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Solar cycle dependence of the seasonal variation of auroral hemispheric power

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Chinese Science Bulletin 2013年第9期58卷 525-530页

作者： ZHENG Ling FU SuiYan ZONG QuiGang parks george WANG Chi CHEN Xi School of Earth and Space Sciences Peking University Space Sciences Laboratory UC Berkeley State key Laboratory of Space Weather Chinese Academy of Sciences

Although much has been done on the hemispheric asymmetry (or seasonal variations) of auroral hemispheric power (HP), the dependence of HP hemispheric asymmetry on solar cycle has not yet been studied. We have analyzed data during 1979-2010 and investigated the dependence of HP hemispheric asymmetry/seasonal variation for the whole solar cycle. Here we show that (1) the hemispheric asymmetry of HP is positively correlated to the value of solar F10.7 with some time delay; (2) it is closely related to the coupling function between the solar wind and magnetosphere; and (3) the winter hemisphere receives more auroral power than the summer hemisphere for kp ~0 to 6. The statistic results can be partly understood in the framework of the ionospheric conductivity feedback model. The similarity and differences between our results and previous results are discussed in the paper.

关键词：太阳活动周期季节变化功率比半球极光不对称性耦合作用模型框架

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Current and electric field observed near the dipolarization front

Current and electric field observed near the dipolarization ...

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2014年中国地球科学联合学术年会——专题29：空间天气与人类活动

作者： Suiyan Fu Weijie Sun Yanbo Cui george parks Peking University SSL UC Berkeley

Dipolarization front is often observed in front of a high speed flow and supposed to be formed by the interaction between the flow plasma and the background *** we report the research results of the current densities associated with dipolarization fronts(DFs)in the geomagnetic tail and electric field associated with DFs using Cluster *** is found that region 1 current sense flowing inside the DFs and region 2 sense just in front of DF(in the Bz dips).Applying multi-spacecraft technique,we evaluate each term in the generalized Ohm’s *** study reveals that in the plasma flow frame there

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Field aligned electrons and current associated with the dipolarization front

Field aligned electrons and current associated with the dipo...

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中国空间科学学会空间物理学专业委员会第十五届全国日地空间物理学研讨会

作者： Suiyan Fu Hao Zheng Bai Xi Sun Weijie george parks Qiugang Zong Zuyin Pu School of Earth and Space Sciences Peking University Space Sciences Laboratory University of California

Strong field-aligned pitch angle distribution of electrons are observed right at the dipolarization front(DF)before the arriving of a high speed flow when the four Cluster satellites are traveling in the plasma sheet on July 22,*** observed electrons with fluxes peak at 1 keV forming a"cool"beam just prior to the dissipation of energy in the current *** field-aligned beams at 15 RE in the plasma sheet are nearly identical to those commonly observed at auroral altitudes,suggesting the beams are aurora electrons accelerated upward by electric fields parallel to the geomagnetic *** field-aligned current contributed by these electrons agrees well with that calculated by the magnetic field observations by four satellites at the *** density of the beams relative to the ambient electron density is 5%3%and the current carried by the beams is strong enough to satisfy the Bohm criteria to initiate current driven *** impact of these field-aligned electrons on the dynamics of the geomagnetic tail is not well understood,however,it is strongly suggested that nonlinear,kinetic effects have to be considered during the dissipation of energy in the earth tail.

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Visible spirals associated with postnoon UV ’bright spots’ aurora

Visible spirals associated with postnoon UV ’bright spots’...

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第十一届全国日地空间物理学术讨论会

作者： george parks Matt Fillingim Natsuo Sato Makoto Taguchi Tohru Araki Asgeir Brekke Syun-Ichi Akasofu Space Science Laboratory University of California Berkeley Space Science Laboratory University of California Berkeley National Institute of Polar Research Tokyo 173-8515 Japan National Institute of Polar Research Tokyo 173-8515 Japan kyoto University kyoto 606-8502 Japan Faculty of Science University of Tromoso Norway International Arctic Research Center Fairbanks USA

＜正＞’Bright spots’ is an auroral feature well observed on postnoon auroral oval by satellite UV imageries. Because of strong atmospheric absorption on UV emissions, however, UV ’bright spots’ cannot be directly observed on the ground. All sky images obtained at Zhongshan in the Antarctic have been used to study the conjugate visible features of ’bright spots’ aurora in Polar UV images covering the northern oval. Two case studies shown for the first time that bright spots in satellite UVI might be associated with spirals along a bright arc aurora in all sky images. Ground observation on aurora spirals with high temporal and spatial resolution camera allowed us to clarify that bright spots might be of the scale of 10-100 km and last for less than 1 minute. Investigation with all-sky images indicates that UV bright spots might display same rotation sense as aurora spirals do, namely, counter-clockwise in magnetic field direction.

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Planning of Recreation parks in the University Campus

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Journal of Environmental Protection 2011年第4期2卷 365-370页

作者： Anthopoulos k. Petros george Costa Democritus University of Thrace Department of Physical Education and Sport Science Komotini Greece.

The benefits of parks and recreation are very serious. The purpose of this study was to investigate the attitudes of the people that use the campus area of Democritus university of Thrace, in komotini. There are series of factors that should be taken under consideration when campus is under planned. In this research took part 742 people and more specific, they were: under graduate students, post graduate students, tutors as well as teaching and administrative staff. An analysis of Principle components has been accomplished and 8 factors have been accrued with eigenvalue more than 1. These factors explain the 55.32% of the whole variation. The conclusion of this study was that a model for campus planning must consists of these 8 parameters: land, climate, vegetation, physical activity, environmental consciousness, daily users of territory and inhabitants of an area.

关键词： Campus Park Physical Activity Questionnaire

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