检索结果-南通市图书馆

The influence of boundary conditions on the distribution of energetic electrons during collisionless magnetic reconnection

引用

Plasma Science and Technology 2024年第4期26卷 79-84页

作者：王磊黄灿陈冬可杨忠炜杜爱民葛亚松 CAS Engineering Laboratory for Deep Resources Equipment and Technology Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029People’s Republic of China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100029People’s Republic of China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190People’s Republic of China

We conducted 2-D particle-in-cell simulations to investigate the impact of boundary conditions on the evolution of magnetic reconnection. The results demonstrate that the boundary conditions are crucial to this evolution. Specifically, in the cases of traditional periodic boundary(PB) and fully-opened boundary(OB) conditions, the evolutions are quite similar before the system achieves the fastest reconnection rate. However, differences emerge between the two cases afterward. In the PB case, the reconnection electric field experiences a rapid decline and even becomes negative, indicating a reversal of the reconnection process. In contrast, the system maintains a fast reconnection stage in the OB case. Suprathermal electrons are generated near the separatrix and in the exhaust region of both simulation cases. In the electron density depletion layer and the dipolarization front region, a larger proportion of suprathermal electrons are produced in the OB case. Medium-energy electrons are mainly located in the vicinity of the X-line and downstream of the reconnection site in both cases. However, in the OB case, they can also be generated in the electron holes along the separatrix. Before the reverse reconnection stage, no high-energy electrons are present in the PB case. In contrast, about 20% of the electrons in the thin and elongated electron current layer are high-energy in the OB case.

关键词： magnetic reconnection electron energization particle-in-cell simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of the magnetization parameter on electron acceleration during relativistic magnetic reconnection in ultra-intense laser-produced plasma

引用

Chinese Physics B 2022年第6期31卷 522-528页

作者：张茜平永利安维明孙伟仲佳勇 Department of Astronomy Beijing Normal UniversityBeijing 100875China CAS Key Laboratory of Geospace Environment University of Science&Technology of ChinaHefei 230026China

Relativistic magnetic reconnection(MR)driven by two ultra-intense lasers with different spot separation distances is simulated by a three-dimensional(3D)kinetic relativistic particle-in-cell(PIC)code.We find that changing the separation distance between two laser spots can lead to different magnetization parameters of the laser plasma environment.As the separation distance becomes larger,the magnetization parameterσbecomes smaller.The electrons are accelerated in these MR processes and their energy spectra can be fitted with double power-law spectra whose index will increase with increasing separation distance.Moreover,the collisionless shocks’contribution to energetic electrons is close to the magnetic reconnection contribution withσdecreasing,which results in a steeper electron energy spectrum.Basing on the3D outflow momentum configuration,the energetic electron spectra are recounted and their spectrum index is close to 1 in these three cases because the magnetization parameterσis very high in the 3D outflow area.

关键词： collisionless shocks magnetic reconnection magnetization parameter electron acceleration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Two-dimensional Modeling of the Tearing-mode-governed magnetic reconnection in the Large-scale Current Sheet above the Two-ribbon Flare

引用

Research in Astronomy and Astrophysics 2022年第8期22卷 125-139页

作者： Yining Zhang Jing Ye Zhixing Mei Yan Li Jun Lin Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China

We attempt to model magnetic reconnection during the two-ribbon flare in a gravitationally stratified solar atmosphere with the Lundquist number of S=10~6 using 2 D simulations.We found that the tearing mode instability leads to inhomogeneous turbulence inside the reconnecting current sheet(CS)and invokes the fast phase of reconnection.Fast reconnection brings an extra dissipation of magnetic field which enhances the reconnection rate in an apparent way.The energy spectrum in the CS shows a power law pattern and the dynamics of plasmoids govern the associated spectral index.We noticed that the energy dissipation occurs at a scale l_(ko)of 100-200 km,and the associated CS thickness ranges from 1500 to 2500 km,which follows the Taylor scale l_(T)=l_(ko)S_(1/6).The termination shock(TS)appears in the turbulent region above flare loops,which is an important contributor to heating flare loops.Substantial magnetic energy is converted into both kinetic and thermal energies via TS,and the cumulative heating rate is greater than the rate of the kinetic energy transfer.In addition,the turbulence is somehow amplified by TS,in which the amplitude is related to the local geometry of the TS.

关键词： magnetic reconnection magnetohydrodynamics(MHD) Sun:flares turbulence

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Precursor Phase of an X-class Flare: magnetic reconnection, Powering and Non-thermal Electrons

引用

Research in Astronomy and Astrophysics 2022年第1期22卷 205-214页

作者： Jinhua Shen Haisheng Ji Yingna Su Xinjiang Astronomical Observatory Chinese Academy of Sciences150 Science 1-StreetUrumqiXinjiang 830011China Laboratory for Dark Matter and Space Science Purple Mountain ObservatoryCASNanjing210023China Purple Mountain Observatory CASNanjing210023China

In this paper,we report three interesting phenomena that occurred during the precursor phase of the X1.6 class flare on 2014 September 10.(1) The magnetic reconnection initiating the flare occurs between one of the two J-shaped magnetic flux ropes that constitute a sigmoidal structure and the overlying sheared magnetic arcade that runs across the sigmoid over its middle part.The reconnection formed an erupting structure that ultimately leads to flare onset.Another J-shaped magnetic flux rope remains unaffected during the whole eruption.The phenomenon is revealed by the observation made by the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory(SDO)at 94 and 131 A.(2) Being simultaneously with starting time of the precursor,photospheric vertical electric current(VEC) around the footpoint region of the overlying magnetic arcade underwent an obvious increase,as observed by the Helioseismic and magnetic Imager(HMI) on board SDO.By only taking into account the VEC with current density over 3σ value(1σ:10 mA m^(-2)),we are able to pick out precursor-associated VEC increase starting from nearly the level of zero.We regard it as a kind of powering process for the magnetic reconnection between the two magnetic loops.(3) With high-resolution narrow-band Helium 10830 A images taken by Goode Solar Telescope at Big Bear Solar Observatory(BBSO),we observe a narrow absorption(dark) front that runs along the erupting magnetic structure(or the erupting hot channel) and moves in the direction of the eruption during the precursor phase.Assuming the excitation mechanism of Helium atoms along the absorption front by non-thermal electrons,the phenomenon shows that the interaction between the erupted hot channel and the overlying(or surrounding)magnetic field has yielded electron acceleration.

关键词： magnetic reconnection Sun:flares Sun:magnetic fields Online material:animation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spontaneous growth of the reconnection electric field during magnetic reconnection with a guide field:A theoretical model and particle-in-cell simulations

引用

Chinese Physics B 2020年第7期29卷 369-374页

作者：黄楷陆全明王荣生王水 Key Laboratory of Geospace Environment Chinese Academy of SciencesDepartment of Geophysics and Planetary ScienceUniversity of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology Hefei 230026China

reconnection electric field is a key element of magnetic reconnection.It quantifies the change of magnetic topology and the dissipation of magnetic energy.In this work,two-dimensional(2D)particle-in-cell(PIC)simulations are performed to study the growth of the reconnection electric field in the electron diffusion region(EDR)during magnetic reconnection with a guide field.At first,a seed electric field is produced due to the excitation of the tearing-mode instability.Then,the reconnection electric field in the EDR,which is dominated by the electron pressure tensor term,suffers a spontaneous growth stage and grows exponentially until it saturates.A theoretical model is also proposed to explain such a kind of growth.The reconnection electric field in the EDR is found to be directly proportional to the electron outflow speed.The time derivative of electron outflow speed is proportional to the reconnection electric field in the EDR because the outflow is formed after the inflow electrons are accelerated by the reconnection electric field in the EDR and then directed away along the outflow direction.This kind of reinforcing process at last leads to the exponential growth of the reconnection electric field in the EDR.

关键词： magnetic reconnection reconnection electric field electron diffusion region particle-in-cell simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the ion distributions at the separatrices during symmetric magnetic reconnection

引用

Earth and Planetary Physics 2021年第2期5卷 205-217页

作者： HongTao Huang YiQun Yu JinBin Cao Lei Dai RongSheng Wang School of Space and Environment Beihang UniversityBeijing 100191China Key Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100191China State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Key Laboratory of Geospace Environment Department of Geophysics and Planetary ScienceUniversity of Science and Technology of ChinaHefei 230026China

A particle-in-cell simulation of symmetric reconnection with zero guide field is carried out to understand the dynamics of ions along the separatrices.Through the investigation of ion velocity distributions at different moments and locations along the separatrices,a typical distribution is found:two counter-streaming populations in the perpendicular direction,with another two populations accelerated into distinct energy levels in the parallel direction.Backward tracing of ions reveals that the counter-streaming cores are mostly composed of ions initially located at the same side of the separatrix,while the other two accelerated populations in the parallel direction are composed of ions crossing through the neutral sheet.Through analysis of energy conversion of these populations,it is found that the ion energization along the separatrix is attributable primarily to the Hall electric field,while that in the region between the two separatrices is caused primarily by the induced reconnection electric field.For the counter-streaming population,the low-energy ions that cross the separatrix twice are affected by both Hall and reconnection electric fields,while the high-energy ions that directly enter the separatrix from the unperturbed plasma are energized mainly by the Hall electric field.For the two energized populations in the parallel direction,the ions with lower-energy are accelerated mainly by the in-plane electric field and the Hall electric field on the opposite side of the separatrix,whereas the ions with higher-energy not only experience the same energization process but also are constantly accelerated by the reconnection electric field.

关键词： magnetic reconnection particle-in-cell simulation energetic particles

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Probing the peripheral self-generated magnetic field distribution in laser-plasma magnetic reconnection with Martin-Puplett interferometer polarimeter

引用

Chinese Physics B 2024年第4期33卷 129-134页

作者：张雅芃姚嘉文刘正东马作霖仲佳勇 Department of Astronomy Beijing Normal UniversityBeijing 100875China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China

magnetic reconnection of the self-generated magnetic fields in laser-plasma interaction is an important laboratory method for modeling high-energy density astronomical and astrophysical phenomena.We use the Martin-Puplett interferometer(MPI)polarimeter to probe the peripheral magnetic fields generated in the common magnetic reconnection configuration,two separated coplanar plane targets,in laser-target interaction.We introduce a new method that can obtain polarization information from the interference pattern instead of the sinusoidal function fitting of the intensity.A bidirectional magnetic field is observed from the side view,which is consistent with the magneto-hydro-dynamical(MHD)simulation results of self-generated magnetic field reconnection.We find that the cancellation of reverse magnetic fields after averaging and integration along the observing direction could reduce the magnetic field strength by one to two orders of magnitude.It indicates that imaging resolution can significantly affect the accuracy of measured magnetic field strength.

关键词： laser-plasma experiment polarimeter self-generated magnetic field magnetic reconnection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Three-dimensional magnetic reconnection in complex multiple X-point configurations in an ancient solar-lunar terrestrial system

引用

Chinese Physics B 2024年第3期33卷 488-495页

作者：何向磊毛傲华孙萌萌邹继同王晓钢 School of Physics Harbin Institute of TechnologyHarbin 150001China Laboratory for Space Environment and Materials Science Harbin Institute of TechnologyHarbin 150001China

magnetic reconnection processes in three-dimensional(3D)complex field configurations have been investigated in different magneto-plasma systems in space,laboratory,and astrophysical systems.Two-dimensional(2D)features of magnetic reconnection have been well developed and applied successfully to systems with symmetrical property,such as toroidal fusion plasmas and laboratory experiments with an axial symmetry.But in asymmetric systems,the 3D features are inevitably different from those in the 2D case.magnetic reconnection structures in multiple celestial body systems,particularly star-planet-Moon systems,bring fresh insights to the understanding of the 3D geometry of reconnection.Thus,we take magnetic reconnection in an ancient solar-lunar terrestrial magneto-plasma system as an example by using its crucial parameters approximately estimated already and also some specific applications in pathways for energy and matter transports among Earth,ancient Moon,and the interplanetary magnetic field(IMF).Then,magnetic reconnection of the ancient lunar-terrestrial magnetospheres with the IMF is investigated numerically in this work.In a 3D simulation for the Earth-Moon-IMF system,topological features of complex magnetic reconnection configurations and dynamical characteristics of magnetic reconnection processes are studied.It is found that a coupled lunar-terrestrial magnetosphere is formed,and under various IMF orientations,multiple X-points emerge at distinct locations,showing three typical magnetic reconnection structures in such a geometry,i.e.,the X-line,the triple current sheets,and the A-B null pairs.The results can conduce to further understanding of reconnection physics in 3D for plasmas in complex magnetic configurations,and also a possible mechanism for energy and matters transport in evolutions of similar astrophysical systems.

关键词： magnetic reconnection multiple X-points complex magneto-plasma system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Out-of-plane shear flow effects on fast magnetic reconnection in a two-dimensional hybrid simulation model

引用

Chinese Physics B 2014年第2期23卷 345-352页

作者：王琳王先驱王晓钢刘悦 MOE Key Laboratory of Materials Modification by Beams and School of Physics & Optoelectronic Technology Dalian University of Technology School of Information Science & Engineering Dalian Polytechnic University State Key Laboratory of Nuclear Physics & Technology and School of Physics Peking University

The effects of out-of-plane shear flows on fast magnetic reconnection are numerically investigated by a two- dimensional （2D） hybrid model in an initial Harris sheet equilibrium with flows. The equilibrium and driven shear flows out of the 2D reconnection plane with symmetric and antisymmetric profiles respectively are used in the simulation. It is found that the out-of-plane flows with shears in-plane can change the quadrupolar structure of the out-of-plane magnetic field and, therefore, modify the growth rate of magnetic reconnection. Furthermore, the driven flow varying along the anti-parallel magnetic field can either enhance or reduce the reconnection rate as the direction of flow changes. Secondary islands are also generated in the process with converting the initial X-point into an O-point.

关键词： out-of-plane magnetic field shear flow magnetic reconnection Hall effects

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Particle-in-cell simulations of low-β magnetic reconnection driven by laser interaction with a capacitor–coil target

引用

Chinese Physics B 2023年第5期32卷 413-420页

作者：原晓霞周沧涛张华李然平永利仲佳勇 Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Advanced Material Diagnostic Technologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118China Department of Astronomy Beijing Normal UniversityBeijing 100875China

The dynamics of low-β magnetic reconnection(MR) driven by laser interaction with a capacitor–coil target are reexamined by simulations in this paper. We compare two cases MR and non-MR(also referred as AP-case and P-case standing for the anti-parallel and parallel magnetic field lines, respectively) to distinguish the different characteristics between them.We find that only in the AP-case the reconnection electric field shows up around the X line and the electron jet is directed toward the X line. The quadruple magnetic fields exist in both cases, however, they distribute in the current sheet area in the AP-case, and out of the squeezing area in the P-case, because electrons are demagnetized in the electron diffusion region in the MR process, which is absent in the P-case. The electron acceleration is dominant by the Fermi-like mechanism before the MR process, and by the reconnection electric field when the MR occurs. A power-law electron energy spectrum with an index of 1.8 is found in the AP-case. This work proves the significant potential of this experimental platform to be applied in the studies of low-β astronomy phenomena.

关键词： magnetic reconnection intense laser low-βplasma

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：