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Test particle simulation on the ion and electron zebra stripes and their time evolution in inner radiation belt

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Science China(Technological Sciences) 2018年第4期61卷 623-632页

作者： WANG YongFu ZONG QiuGang zhou xuzhi State Key Laboratory of Nuclear Physics and Technology School of Physics and Fusion Simulation CenterPeking University Institute of Space Physics and Applied Technology Peking University Key Laboratory of Earth and Planetary Physics Chinese Academy of Sciences

During February 15–16, 2014, the energetic electron spectrogram for four successive inner radiation belt crossing show clearly the electron zebra structures and their time evolution which last for about 17 h. Unfortunately, the time of flight(TOF) in RBSPICE measurement is turned off below 3 RE, and the ion measurement is contaminated by electrons. Thus in this study we studied the differences between the ion and electron zebra stripe structures and their time evolution using simple theory and test particle simulation, combining the electron measurement from RBSIPICE onboard Van Allen Probes. Theoretical analysis predicts that the ion zebra stripe structures should lie at a higher energy range than the corresponding electron zebra stripe structures due to that the directions of gradient B drift and corotation E×B drift are the same for electrons while opposite for ions. Test particle simulation with the dipole magnetic field and Volland-Stern electric field model have shown that the ion and electron zebra stripe structures could be produced by the convection electric field penetrating into the inner magnetosphere in this event, with their time evolution determined by total drift velocity that are different for ions and electrons. The predicted differences between the ion and electron zebra stripe structures are partially verified through observation. The ion zebra stripe structures could have potential influence to the ring current.

关键词： inner radiation belt ion zebra stripes energetic ions energetic electrons

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

Ultralow frequency wave characteristics extracted from particle data:Application of IGSO observations

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Science China(Technological Sciences) 2017年第3期60卷 419-424页

作者： LI Li zhou xuzhi ZONG QiuGang CHEN XingRan ZOU Hong REN Jie HAO YiXin ZHANG XianGuo Institute of Space Physics and Applied Technology Peking University College of Astronautics Nanjing University of Aeronautics and Astronautics State Key Laboratory of Space Weather National Space Science CenterChinese Academy of Sciences

3 Summary and discussion In the generalized drift resonance theory[17],a characteristic signature of the ULF wave-particle interactions is the increasingly-tilted stripes in the particle energy *** phase difference ac... 详细信息

关键词： ultralow frequency waves wave-particle interactions drift resonance ULF wave characteristics

Numerical study on ULF waves in a dipole field excited by sudden impulse

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Science China(Technological Sciences) 2008年第10期51卷 1665-1676页

作者： YANG Biao FU SuiYan ZONG QiuGang WANG YongFu zhou xuzhi PU ZuYin XIE Lun Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China Center for Atmospheric Research University of Massachusetts LowellLowellMA 01854-3629USA

A three-dimensional numerical model is employed to investigate ULF waves ex-cited by the sudden impulse (SI) of the solar wind dynamic pressure interacting with a dipole magnetosphere. We focus on the solar wind-magnetosphere energy coupling through ULF waves, and the influences of the SI spectrum on the cavity mode structure and the energy deposition due to field line resonances (FLRs) in the magnetosphere. The numerical results show that for a given SI lasting for 1 min with amplitude of 50 mV/m impinging on the subsolar magnetopause, the total ULF energy transported from the solar wind to the magnetosphere is about the magni-tude of 1014 J. The efficiency of the solar wind energy input is around 1%, which depends little on the location of the magnetopause in the model. It is also found that the energy of the cavity mode is confined in the region near the magnetopause, whereas, the energy of the toroidal mode may be distributed among a few specific L-shells. With a given size of the model magnetosphere and plasma density distri-bution, it is shown that the fundamental eigenfrequency of the cavity mode and the central locations of the FLRs do not vary noticeably with the power spectrum of the SI. It is worth noting that the spectrum of the SI affects the excitation of higher harmonics of the global cavity mode. The broader the bandwidth of the SI is, the higher harmonics of cavity mode could be excited. Meanwhile, the corresponding FLRs regions are broadened at the same time, which implies that the global cavity modes and toroidal modes can resonate on more magnetic L-shells when more harmonics of the global cavity modes appear.

关键词： sudden impulse ULF waves global cavity mode toroidal mode field line resonances

Multi-spacecraft observations of ULF waves during the recovery phase of magnetic storm on October 30, 2003

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Science China(Technological Sciences) 2008年第10期51卷 1772-1785页

作者： YongFu Wang SuiYan Fu QiuGang Zong Biao Yang ZuYin Pu Lun Xie xuzhi zhou Institute of Space Physics and Applied Technology Peking University Beijing 100871 China Center for Atmospheric Research University of Massachusetts Lowell Lowell MA 01854-3629 USA

Based on observations obtained by Cluster C1, GOES 10, 12, and Polar, the global ULF wave properties are studied during the recovery phase of a very intense magnetic storm-Halloween storm (October 31, 2003, 21:00–23:00 UT). The results indicate that the ULF waves’ properties observed by different satellites, such as amplitude, period, etc. show large variations. This can be interpreted as that Field Line Resonance (FLR) might take place in the region where Cluster C1 passed. The compressional wave of the cavity mode coupled with FLR’s shear Alfven wave and fed energy to the latter, forming a large-amplitude toroidal mode. From the point of period, Cluster C1 observed the shortest period, GOES 10, 12 observed the middle, while Polar observed the longest. The wave period of toroidal mode observed by Cluster C1 kept almost unchanging when Cluster C1 passed L range from 11.7 to 5.3. Using the Squared Wavelet Coherence analysis method, we estimated that the FLR region in the dayside magnetosphere could expand to at least 4 local time widths. The toroidal mode observed by Polar was a standing wave, while the poloidal mode was a propagating wave, the observation results could be well explained by the waveguide mode theory. Since the solarwind speed V x was −800 km/s and the dynamic pressure varied little, we speculated that the source of the ULF wave was the Kelvin-Helmholtz instability at the magnetopause triggered by high speed solarwind.

关键词： magnetic storm ULF wave poloidal mode toroidal mode compressional mode cavity mode Field Line Resonance (FLR)

Magnetotail dipolarization fronts and particle acceleration:A review

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Science China Earth Sciences 2020年第2期63卷 235-256页

作者： Huishan FU Elena EGRIGORENKO Christine GABRIELSE Chengming LIU San LU KJHWANG xuzhi zhou Zhe WANG Fang CHEN School of Space and Environment Beihang UniversityBeijing 102206China Space Research Institute of RAS MoscowRussia Earth Planetaryand Space Sciences DepartmentUniversity of CaliforniaLos AngelesUSA Southwest Research Institute San AntonioUSA Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China

In this paper, the particle acceleration processes around magnetotail dipolarization fronts(DFs) were reviewed. We summarize the spacecraft observations(including Cluster, THEMIS, MMS) and numerical simulations(including MHD, testparticle, hybrid, LSK, PIC) of these processes. Specifically, we(1) introduce the properties of DFs at MHD scale, ion scale, and electron scale,(2) review the properties of suprathermal electrons with particular focus on the pitch-angle distributions,(3)define the particle-acceleration process and distinguish it from the particle-heating process,(4) identify the particle-acceleration process from spacecraft measurements of energy fluxes, and(5) quantify the acceleration efficiency and compare it with other processes in the magnetosphere(e.g., magnetic reconnection and radiation-belt acceleration processes). We focus on both the acceleration of electrons and ions(including light ions and heavy ions). Regarding electron acceleration, we introduce Fermi,betatron, and non-adiabatic acceleration mechanisms;regarding ion acceleration, we present Fermi, betatron, reflection, resonance, and non-adiabatic acceleration mechanisms. We also discuss the unsolved problems and open questions relevant to this topic, and suggest directions for future studies.

关键词： Dipolarization front Electron acceleration Ion acceleration Magnetic reconnection Review Reconnection front

Radial propagation of magnetospheric substorm-injected energetic electrons observed using a BD-IES instrument and Van Allen Probes

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Science China Earth Sciences 2016年第7期59卷 1508-1516页

作者： ZONG QiuGang HAO YiXin ZOU Hong FU SuiYan zhou xuzhi REN Jie WANG LingHua YUAN ChongJing LIU ZhiYang JIA XiangHong QUAN Lin LIU Ying WANG YongFu Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China Institute of Geology and Geophysics Chinese Atcademy of SciencesBeijing 100029China State Key Laboratory of Space Medicine Fundamentals and Application Chinese Astronaut Research and Training CenterBeijing 100094China Beijing Institute of Tracking and Telecommunications Technology Beijing 100094China

In cases where substorm injections can be observed simultaneously by multiple spacecraft,they can help elucidate the potential mechanisms of particle transport and energization,of great importance to understanding and modeling the *** this paper,using data returned from the BeiDa-IES（BD-IES） instrument onboard a satellite in an inclined（55°） geosynchronous orbit（IGSO）,in combination with two geo-transfer orbiting（GTO） satellite Van Allen Probes（A and B）,we analyze a substorm injection event that occurred on the 16 th of October *** this substorm injection,the IGSO onboard BD-IES was outbound,while both Van Allen Probe satellites（A and B） were inbound,a configuration of multiple trajectories that provides a unique opportunity to simultaneously investigate both the inward and outward radial propagation of substorm *** by AE/AL indices,this substorm was closely related to an IMF/solar wind discontinuity that showed a sharp change in IMF Bz direction to the *** innermost signature of this substorm injection was detected by Van Allen Probes A and B at L-3.7,while the outermost signature was observed by the onboard BD-IES instrument at *** data indicate that the substorm had a global,rather than just local,***,we suggest that electric fields carried by fast-mode compressional waves around the substorm injection are the most likely candidate mechanism for the electron injection signatures observed in the inner- and outermost inner magnetosphere.

关键词： Substonn injection Energetic electrons Energetic particle acceleration Drift Dispersionless injection

Corotating drift-bounce resonance of plasmaspheric electron with poloidal ULF waves

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Earth and Planetary Physics 2017年第1期1卷 2-12页

作者： Qiu-Gang Zong YongFu Wang Jie Ren xuzhi zhou SuiYan Fu Robert Rankin Hui Zhang Institute of Space Physics and Applied Technology Peking University Department of Physics University of Alberta Physics Department and Geophysical Institute University of Alaska Fairbanks

The purpose of this paper is to understand how low energy plasmaspheric electrons respond to ULF waves excited by interplanetary shocks impinging on magnetosphere. It is found that both energy and pitch angle dispersed plasmaspheric electrons with energy of a few eV to tens of eV can be generated simultaneously by the interplanetary shock. The subsequent period of successive dispersion signatures is around 40 s and is consistent with the ULF wave period(third harmonic). By tracing back the energy and pitch angle dispersion signatures, the position of the electron injection region is found to be off-equator at around -32° in the southern hemisphere. This can be explained as the result of injected electrons being accelerated by higher harmonic ULF waves(e.g. third harmonic) which carry a larger amplitude electric field off-equator. The dispersion signatures are due to the flux modulations(or accelerations) of " local" plasmaspheric electrons rather than electrons from the ionosphere. With the observed wave-borne large electric field excited by the interplanetary shock impact, the kinetic energy can increase to a maximum of 23 percent in one bouncing cycle for plasmaspheric electrons satisfying the drift-bounce resonance condition by taking account of both the corotating drift and bounce motion of the local plasmaspheric electron.

关键词： drift-bounce resonance plasmaspheric electron poloidal mode ULF wave

Monte Carlo simulations of the sensor head of imaging energetic electron spectrometer onboard a Chinese IGSO navigation satellite

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Science China(Technological Sciences) 2019年第7期62卷 1169-1181页

作者： ZOU Hong YE YuGuang ZONG QiuGang CHEN HongFei LUO Lin zhou xuzhi CHEN XingRan HAO YiXin REN Jie WANG YongFu SHI WeiHong YU XiangQian JIA XiangHong XU Feng ZHANG XiaoXin Institute of Space Physics and Applied Technology Peking University Beijing 100871 China State Key Laboratory of Space Medicine Fundamentals and Application Chinese Astronaut Research and Training Center Beijing 100094 China Key Laboratory of Space Weather National Center for Space Weather Beijing 100081 China

An imaging energetic electron spectrometer built by the Peking University team(BD-IES) onboard a Chinese navigation satellite in an inclined GEO orbit has been launched successfully in September 2015, which measures the spectra of the energetic electrons with the energy range of 50–600 keV in nine directions. In this study, Monte Carlo simulations of the BD-IES sensor head were performed using Geant4 and the corresponding characteristic responses to the isotropic energetic particles were derived. The effective geometric factors were estimated using the typical electron and proton spectra in the GEO orbit and the corresponding simulated sensor head responses. It was found that the average effective geometric factors of nine directions are close to the nominal geometric factors calculated with the traditional method, but the effective geometric factor decreases as the center energy of the energy channel decreases. The BD-IES sensor head also responses to the energetic protons, but the average contamination rate of all 72 channels is about 2%, which means that the proton contamination is acceptable. The spectra of the energetic electrons measured by BD-IES are derived using the effective geometric factors of the sensor head and are comparable with the spectra measured by the magnetic electron ion spectrometer(MagEIS) instrument onboard Van Allen Probes.

关键词： Monte Carlo simulation pin-hole imaging system geometric factor imaging energetic electron spectrometer IGSO satellite