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The response of plasma parameters and energy transport in the plasma sheet to interplanetary magnetic field B_z

Science China(Technological Sciences) 2021年第7期64卷 1528-1534页

作者： REN GanMing CAO JinBin YANG Jian dunlop malcolm Wray School of Space and Environment Beihang UniversityBeijing100191China Key Laboratory of Space Environment Monitoring and Information Processing of MIIT Beijing102206China

We use 9 years data of Cluster to study the dependencies of plasma parameters and energy transport in the plasma sheet on the lasting time of northward/southward interplanetary magnetic field(IMF). The plasma parameters and energy transport in the plasma sheet always respond to the change of IMF direction by more or less time. The ion density starts to increase/decrease remarkably at 80 min after northward/southward IMF turning. The ion temperature starts to decrease at 25 min after northward IMF turning, whereas it starts to increase at 80 min after southward IMF turning. The earthward convection velocity within15 min after northward IMF turning almost equals to that within 15 min period after southward IMF turning. However at time greater than 15 min after southward IMF turning, the earthward convection velocity under southward IMF starts to remarkably increase. The response time(15 min) of magnetospheric convection velocity is well consistent with the response times of nightside ionospheric convection to southward IMF turning. The enthalpy flux is larger than kinetic flux by about three orders of magnitudes, and thus the enthalpy flux plays a dominant role in the plasma sheet energy transport. The enthalpy flux does not weaken immediately after northward IMF turning. The enthalpy flux within 15 min after northward IMF turning is comparable to or even slightly larger than that within 15 min after southward IMF. The enthalpy flux starts to decrease at times greater than15 min after northward IMF turning, whereas it starts to increase at times greater than 15 min after southward IMF turning. The result that the enhanced energy transport during the 15 min period after northward IMF turning may explain previous observation that substorms frequently occur shortly after northward IMF turning.

关键词： plasma sheet energy transport enthalpy flux response time

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Multi-spacecraft observations of earthward flow bursts

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Science China(Technological Sciences) 2012年第5期55卷 1305-1311页

作者： MA YuDuan CAO JinBin REME Henry DANDOURAS Iannis dunlop malcolm LUCEK Elisabeth School of Astronautics Beihang UniversityBeijing 100191China SOA Key Laboratory for Polar Science Polar Research Institute of ChinaShanghai 200136China Centre d'Etude Spatiale des Rayonnements Toulouse 31028France RutherforAppleton Laboratory OxfordshireUK Blackett Laboratory Imperial College LondonLondon SW72AZUK

On the basis of the plasma, electric and magnetic fields jointly observed by Cluster and the Double Star TC-I spacecraft in the Earth＇s magnetotail, we have investigated the earthward flow bursts by introducing the momentum equation in the X-direction in the ideal conditions of magneto hydrodynamics （MHD）. One earthward flow burst with a peak in excess of 500 km/s was selected, when the four spacecraft of Cluster were located around -16 RE and TC-1 was located around -10 RE in the X-direction. The inter-spacecraft distances in Y and Z directions were smaller than the statistical spatial scales of the bursty bulk flows. When the Y components of E and -VxB were compared, there was no clear breakdown of the frozen-in condition during the earthward flow burst. With the measured plasma and magnetic parameters from two spacecraft at different positions in the magnetotail, the X component of the pressure gradient was calculated. Magnetic tension was calculated using the mag- netic field measured at four points, which could be compared with the assumed constant in the past research with single satel- lite. When the pressure gradient and the magnetic tension were put into the MHD momentum equation, some samples of the earthward flow bursts were accelerated and some were decelerated. The braking process of the earthward flow burst was more complicated than what the past results had shown. The accelerated samples accounted for about one third of the whole earth- ward flow bursts and discontinuously located among the decelerated elements. The original single earthward flow burst event might be split into several short flow bursts when it was moving to the Earth. Our results may partly illustrate that the duration of fast flows during three phases of substorm becomes short near the Earth. The results are consistent with the past results that fast flows intrude to places earthward the typical braking region.

关键词： flow burst pressure gradient magnetic tension braking

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SuperDARN CUTLASS Finland radar observations of high-latitude magnetic reconnections under northward interplanetary magnetic field (IMF) conditions

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Science China(Technological Sciences) 2012年第5期55卷 1207-1216页

作者： ZHANG QingHe LIU RuiYuan YANG HuiGen HU HongQiao ZHANG BeiChen dunlop malcolm LESTER Mark BOGDANOVA Yulia WALSH Andrew SOA Key Laboratoryfor Polar Science Polar Research Institute of ChinaShanghai 200136China Space Science Department Rutherford-Appleton LaboratoryChiltonDidcotUK Department of Physics and Astronomy University of LeicesterLeicesterUK Mullard Space Science Laboratory University College LondonDorkingSurreyUK

A number of backscatter power enhancement events with ＂equatorward-moving radar auroral forms＂ in the high-latitude ionosphere were observed by SuperDARN CUTLASS Finland radar when the IMF was northward during 09：00 -10：00 UT on 26 March 2004. These events were also associated with sunward flow enhancements at each location in the Northern Hemisphere which were shown in ionospheric convections measured by the SuperDARN radars. These are typical features of high-latitude （lobe） magnetic reconnections. The durations of the velocity enhancements imply that the evolution time of the lobe reconnec- tions is about 8-16 rain from their origin at the reconnection site to their addition to the magnetotall lobe again. In additional, the Double Star TC-1 spacecraft was moving from magnetosheath into magnetosphere, and crossing the magnetopause near the subsolar region during this interval, and observed typical low-latitude magnetic reconnection signatures. This infers that the dayside high- and low-latitude reconnections may occur simultaneously.

关键词： high-latitude magnetic reconnection equatorward-moving radar auroral form evolution time of the lobe reconnections

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磁尾的等离子体片边界层场向电流密度与地磁活动指数Kp的关系分析

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中国科学：技术科学 2011年第11期41卷 1499-1504页

作者：程征伟史建魁 ZHANG Tie Long dunlop malcolm 刘振兴中国科学院空间科学与应用研究中心空间天气学国家重点实验室北京100190 Space Research Institute Austrian Academy of Sciences Graz A-8010 Austria SSTD Rutherford Appleton Laboratory SW7 2AZ UK

对2001年7月～10月Cluster穿越磁尾等离子体片边界层期间观测到的172个场向电流事件进行了研究,主要分析了等离子体片边界层场向电流特性与地磁活动指数之间的关系.研究结果表明:1)等离子体片边界层场向电流的相对发生率随地磁活动的增... 详细信息

对2001年7月～10月Cluster穿越磁尾等离子体片边界层期间观测到的172个场向电流事件进行了研究,主要分析了等离子体片边界层场向电流特性与地磁活动指数之间的关系.研究结果表明:1)等离子体片边界层场向电流的相对发生率随地磁活动的增强而增加;2)等离子体片边界层场向电流密度随Kp指数的增大而增大;在磁暴的主相阶段,场向电流迅速增大,电流密度最大达到19.05nA/m2,同时Kp增大至5;3)地磁活动指数Kp与等离子体片边界层区场向电流密度有着一致的变化关系.然而,当AE800nT时,场向电流密度随着AE的增加而减小.从而说明,等离子体片边界层场向电流密度与Kp指数的变化关系更为密切.

关键词：场向电流等离子体片边界层 Kp指数 AE指数

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Evolution of clustered magnetic nulls in a turbulent-like reconnection region in the magnetotail

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Science Bulletin 2016年第24期61卷 1145-1150页

作者： Ruilong Guo Zuyin Pu Suiyan Fu Lun Xie malcolm dunlop Yulia V. Bogdanova Jiansen He Xin Wang Zhonghua Yao School of Earth and Space Sciences Peking UniversityBeijing 100871 China PKU/UCLA Joint Research Institute in Science and Engineering Peking University Beijing 100871 China School of Astronautics Beihang University Beijing 100191China RAL Space Rutherford Appleton Laboratory STFCDidcot OXll 0QX UK UCL Mullard Space Science Laboratory Dorking RH5 6NT UK

t Magnetic null points and flux ropes play important roles in the three-dimensional process of magnetic reconnection. In this study, a cluster of null points are reconstructed in the reconnection region in the magnetotail by applying a fitting-reconstruction method to measurements from the Cluster mission. The number of recon- structed null points varies rapidly, presenting a turbulentlike evolution of the magnetic structure. The electron density and the flux of the accelerated electrons were enhanced in this turbulent-like region. During this unstable reconnection process, a B-As-B null structure was formed, showing flux rope features and resembling a secondary island in the observation.

关键词： Magnetic reconnection - Turbulent Magnetic null point Flux ropes Magnetotail

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大肠肿瘤遗传不稳定对APC基因突变的影响

大肠肿瘤遗传不稳定对APC基因突变的影响

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第六次全国大肠癌会议暨中日韩大肠癌会议

作者：黄建郑树 malcolm dunlop 浙江医科大学附属二院英国MRC爱丁堡人类遗传所

目的研究大肠肿瘤微卫星不稳定(MI)／复制差错(RER)与APC基因突变的相关性。方法 115例non—FAP大肠肿瘤病例,由IVSP法(体外蛋白合成试验)检测APC突变并序列分析证实;MI／RER测定由序列分析仪或银染法完成。结果 76例APC突变病例包括29...

目的研究大肠肿瘤微卫星不稳定(MI)／复制差错(RER)与APC基因突变的相关性。方法 115例non—FAP大肠肿瘤病例,由IVSP法(体外蛋白合成试验)检测APC突变并序列分析证实;MI／RER测定由序列分析仪或银染法完成。结果 76例APC突变病例包括29例RER 和47例RFR。两型肿瘤具有相似的APC突变率(56％ VS 75％,P＜0.05)和分布,但有明显不同的突变谱,RER+易发生移码突变(70％ VS 47％,P＜0.04),且多发生在单或双碱基重复序列 (57 ％VS 19％,P＜0.01)尤其A(n)处(49％ VS 11％,P＜0.01)。结论 RER+与—肿瘤的形成有共同的ARC途径,但RER反映的遗传不稳定可能早于APC突变。

关键词：

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大肠肿瘤错配修复缺陷与APC基因突变的关系

大肠肿瘤错配修复缺陷与APC基因突变的关系

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“科技增强国力，青年开创未来——携手走向辉煌的新世纪”中国科协第三届青年学术年会

作者：黄建郑树 malcolm dunlop 浙江医科大学附属第二医院

本文就错配修复基因突变表型-复制差错(RER)与APC突变的相关性进行研究。在115例Non-FAP大肠肿瘤中,由IVSP检出APC突变病例76例(RER阳性29例,阴性47例)。研究发现:两型肿瘤具有相似的APC突变率(56%和75%)和分布;但有明显不同的突变谱,RE... 详细信息

本文就错配修复基因突变表型-复制差错(RER)与APC突变的相关性进行研究。在115例Non-FAP大肠肿瘤中,由IVSP检出APC突变病例76例(RER阳性29例,阴性47例)。研究发现:两型肿瘤具有相似的APC突变率(56%和75%)和分布;但有明显不同的突变谱,RER阳性易发生移码突变(70%和47%,P<0.05),且多发生在单或双碱基重复序列(57%和19%,P<0.01);尤其A(n)处(49%和11%,P<0.01)。结果表明:RER阳性与RER阴性肿瘤的形成有共同的APC途径,RER反映的遗传不稳定早于APC突变。该研究对认识大肠肿瘤的最早期分子改变进而早期诊断有重要意义。

关键词：大肠肿瘤复制差错 APC基因

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不同高度处极尖区位置对地磁偶极倾角的依赖程度

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科学通报 2013年第28期58卷 1264-1264页

作者：郭建广史建魁程征伟张子迎王铮张铁龙刘振兴 dunlop malcolm 中国科学院国家空间科学中心空间天气学国家重点实验室北京100190 国家卫星气象中心北京100081 Space Research Institute Austrian Academy of SciencesGrazA-8042Austria Rutherford Appleton Laboratory ChiltonDidcotOX110QXUK

由于太阳风与地球磁层相互作用以及地磁偶极倾角的存在,地球磁层极尖区的位置在不断变化.这种变化不仅与太阳风参数的扰动变化有关,而且与地磁偶极轴运动状态有关.关于极尖区位置对地磁偶极倾角的依赖程度问题,

关键词：磁偶极极尖区倾角位置地球磁层相互作用运动状态太阳风

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Relationship between FAC at plasma sheet boundary layers and AE index during storms from August to October,2001

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Science China(Technological Sciences) 2008年第7期51卷 842-848页

作者： dunlop M Imperial College London London SW7 2AZ UK

Unlike the previous single (dual) satellite observation, the four Clusterll satellites make it possible to directly compute the continuous field-aligned current (FAC) density according to the magnetic data from them and to enable the investigation of the relationship between the FAC and geomagnetic activity. This paper analyzes the observation data when the Cluster satellites crossed the plasma sheet boundary layer (PSBL) in the magnetotail during the two magnetic storms in August to October 2001. According to the data, during the magnetic storms the relationship between the variations of FAC and AE index turned out to be: 1) FAC was obviously increasing during the storms; 2) FAC density was approximately negatively correlated with AE index from the sudden commencement to the early main phase of the storm; 3) they were approximately positively correlated during the late main phase and early recovery phase; 4) they were no apparent correlation during the late recovery phase.

关键词： ionosphere-magnetosphere storm cases FAC AE index

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Observations of the step-like accelerating processes of cold ions in the reconnection layer at the dayside magnetopause

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Science Bulletin 2018年第1期63卷 31-37页

作者： Qinghe Zhang Michael Lockwood John C.Foster Qiugang Zong malcolm W.dunlop Shunrong Zhang Joran Moen Beichen Zhang Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China Department of Meteorology University of ReadingReading RG6 6BBUK MIT Haystack Observatory WestfordMA 01886USA School of Earth and Space Sciences Peking UniversityBeijing 100087China Space Sciences Division SSTDRutherford Appleton LaboratoryDidcot OX11 OQXUK Department of Physics University of OsloBlindern 0316OsloNorway SOA Key Laboratory for Polar Science Polar Research Institute of ChinaShanghai 200136China

Cold ions of plasmaspheric origin have been observed to abundantly appear in the magnetospheric side of the Earth's magnetopause. These cold ions could affect the magnetic reconnection processes at the magnetopause by changing the Alfvén velocity and the reconnection rate, while they could also be heated in the reconnection layer during the ongoing reconnections. We report in situ observations from a partially crossing of a reconnection layer near the subsolar magnetopause. During this crossing, step-like accelerating processes of the cold ions were clearly observed, suggesting that the inflow cold ions may be separately accelerated by the rotation discontinuity and slow shock inside the reconnection layer.

关键词： Cold ions Magnetic reconnection Ion accelerations Magnetopause

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