Calibration of AC Vector Magnetometer Based on Ellipsoid Fitting
作者：
Yu, XiangQian;Xiao, ChiJie* ;Liu, Si;Zong, QiuGang;Qu, YaNan;...
期刊：
IEEE Transactions on Instrumentation and Measurement ,2021年70:1-6 ISSN：0018-9456
通讯作者：
Xiao, ChiJie
作者机构：
[Yu, XiangQian; Chen, Ao; Song, SiYu; Zong, QiuGang; Zou, Hong; Chen, HongFei; Shi, WeiHong; Wang, YongFu] Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China.;[Xiao, ChiJie] Peking Univ, Sch Phys, Beijing 100871, Peoples R China.;[Liu, Si] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410114, Peoples R China.;[Qu, YaNan; Gao, Shuang; Shao, SiPei] Inst Shandong Aerosp Technol, Yantai 264003, Peoples R China.
通讯机构：
[Xiao, ChiJie] P;Peking Univ, Sch Phys, Beijing 100871, Peoples R China.
关键词：
AC vector magnetometer;angular misalignments and offset errors;ellipsoid fitting;scaling factors
摘要：
AC vector magnetometers have recently become increasingly widespread. The calibration of ac vector magnetometers before use is critical. Based on traditional ellipsoid fitting, which is suitable for calibrating dc vector magnetometers, a method suitable for calibrating ac vector magnetometers is presented. Simulation analysis and experimental verification demonstrate that this method is effective in calibrating ac vector magnetometers, including scaling factors, angular misalignments, and offset errors. © 1963-2012 IEEE.
语种：
英文
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Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature 2019 tech.scichina.com link.springer.com Upward propagation of lightning-generated whistler waves into the radiation belts
作者：
Guo, MingYue;Zhou, QingHua;Xiao, FuLiang* ;Liu, Si;He, YiHua;...
期刊：
中国科学:技术科学(英文版) ,2020年63(2):243-248 ISSN：1674-7321
通讯作者：
Xiao, FuLiang
作者机构：
[Xiao, FuLiang; Yang, Chang; Guo, MingYue; Liu, Si; He, YiHua; Zhou, QingHua] Changsha Univ Sci, Sch Phys, Elect Sciences, Technology, Changsha, Peoples R China.
通讯机构：
[Xiao, FuLiang] C;Changsha Univ Sci, Sch Phys, Elect Sciences, Technology, Changsha, Peoples R China.
关键词：
lightning-generated whistler waves;radiation belts;numerical simulation
摘要：
Lightning-generated whistler (LGW) waves which induce energetic electron precipitation provide an important coupling between the ionosphere and radiation belts. Using the ray-tracing technique, we examine the propagation behaviour of LGW waves and show that they can travel upward into the radiation belts during higher geomagnetic activities due to the plasmapause inward compression, particularly in cases of lower wave frequencies, lower wave normal angles and azimuthal angles. Both perpendicular and parallel group velocities of LGW waves remain in relatively small values inside the plasmasphere but change rapidly to high values outside the plasmasphere. The launching latitude increases with increasing LGW wave normal angle. These results here further reveal a detailed picture on how LGW waves escape out of the plasmasphere and onto the radiation belts.
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英文
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Excitation of Highly Oblique Lower Band and Upper Band Chorus by a Loss Cone Feature and Temperature Anisotropy Distribution
作者：
Zhou, Qinghua;Yang, Chang;He, Yihua;Liu, Si;Gao, Zhonglei;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2019年46(4):1929-1936 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Xiao, Fuliang; Gao, Zhonglei; Zhou, Qinghua; He, Yihua; Liu, Si] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Xiao, Fuliang; Zhou, Qinghua] Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.;[Xiao, Fuliang; Zhou, Qinghua] Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monito, Changsha, Hunan, Peoples R China.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monito, Changsha, Hunan, Peoples R China.
关键词：
highly oblique chorus;wave-particle interaction;RBSP results;radiation belts
摘要：
Recent studies have indicated that highly oblique lower band chorus could be excited by temperature anisotropy with a low-energy electron plateau. Here we present another excitation mechanism of highly oblique lower and upper band chorus by using the simultaneous observations and numerical modeling. During 23:00–24:00UT on 3 July 2016, Van Allen probe A observed chorus with the wave normal angle close to the resonance cone both in the lower and upper bands around L=5.0 and MLT=3. Enhanced flux and pitch angle anisotropy of energetic electrons were observed in the same spatial region. Calculations of chorus growth rates show that highly oblique chorus waves can be excited by the energetic electrons with a loss cone feature and distinct temperature anisotropy, particularly more efficient in the presence of a low-energy plateau. The temperature anisotropy for the oblique upper band is higher than that for the lower band. ©2019. American Geophysical Union. All Rights Reserved.
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英文
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Magnetospheric Multiscale Observation of Quasiperiodic EMICWaves Associated With Enhanced Solar Wind Pressure
作者：
Liu, Si;Xia, Zhiyang;Chen, Lunjin* ;Liu, Yang;Liao, Zedong;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2019年46(13):7096-7104 ISSN：0094-8276
通讯作者：
Chen, Lunjin
作者机构：
[Liao, Zedong; Liu, Si; Liu, Yang] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Chen, Lunjin; Zhu, Hui; Liu, Si; Xia, Zhiyang] Univ Texas Dallas, Dept Phys, William B Hanson Ctr Space Sci, Richardson, TX 75083 USA.;[Liao, Zedong; Liu, Si; Liu, Yang] Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.
通讯机构：
[Chen, Lunjin] U;Univ Texas Dallas, Dept Phys, William B Hanson Ctr Space Sci, Richardson, TX 75083 USA.
关键词：
instability modulation;quasi-periodic EMIC waves;solar wind pressure;ULF waves
摘要：
We present a Magnetospheric Multiscale mission observation of quasiperiodic electromagnetic ion cyclotron (EMIC) variations on 24 December 2015 corresponding to magnetic field depressions as well as proton pitch angle anisotropy enhancements. Proton dynamic pressure obtained by WIND indicates that the solar wind was periodically compressing the magnetosphere with a period ∼7.5min, which is consistent with the EMIC modulation period observed by the Magnetospheric Multiscale. Numerical calculations demonstrate that the EMIC modulation period is comparable with the magnetic field line resonance period, suggesting that quasiperiodic solar wind enhancement compressing the magnetosphere and propagating as the fast mode can lead to the magnetic field line oscillation and hence the presence of quasiperiodic magnetic compressions and discrete proton anisotropy elements, which provides optimal conditions for modulating the EMIC instability. Current results provide a complete chain of self-consistent observational evidences to illustrate the process connecting solar wind variations to EMIC wave amplitude modulation in the magnetosphere. ©2019. American Geophysical Union. All Rights Reserved.
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英文
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基于单片机的高分辨率多通道数据采集系统
作者：
张健;刘斯;刘洋
期刊：
电子技术与软件工程 ,2019年(5):238 ISSN：2095-5650
作者机构：
长沙理工大学物理与电子科学学院;[刘洋; 刘斯; 张健] 长沙理工大学
关键词：
多通道;高分辨率;单数据采集
摘要：
为了实现对传感器输出模拟信号的数字化处理,本文详细介绍了一款基于STC89C54单片机和AD7734芯片的三通道数据采集系统。本系统能够同步对三路模拟电压数据进行24位采集,测量范围为±10V(电压分辨率1.192μV),采样频率50Hz。本系统具有SD卡实时存储和串口通信功能。实验结果表明,本系统测量平均相对误差为0.007%,非线性度为0.002%FS,均方根噪声为44.754μV。
语种：
中文
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Global Occurrences of Electrostatic Electron Cyclotron Harmonic Waves Associated With Radiation Belt Electron Distributions
作者：
Chen, Yaru;Zhou, Qinghua;He, Yihua;Yang, Chang;Liu, Si;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2019年46(10):5028-5033 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Chen, Yaru; Xiao, Fuliang; Gao, Zhonglei; Zhou, Qinghua; He, Yihua; Liu, Si] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Chen, Yaru; Xiao, Fuliang; Zhou, Qinghua] Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.;[Chen, Yaru; Xiao, Fuliang; Zhou, Qinghua] Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha, Hunan, Peoples R China.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha, Hunan, Peoples R China.
关键词：
Electrostatic electron cyclotron harmonic waves;electron ring distribution;global occurrences;radiation belt;Van Allen Probe observation
摘要：
<jats:title>Abstract</jats:title><jats:p>Electrostatic electron cyclotron harmonic (ECH) waves can yield diffuse aurora primarily at higher <jats:italic>L</jats:italic>‐shells by driving efficient precipitation loss of plasma sheet electrons. Here using the Van Allen Probes high resolution data, we examine in detail the global occurrences of ECH waves during the period from 1 October 2012 to 30 June 2017 and find that there are totally 419 events of enhanced ECH waves. The statistical results demonstrate that ECH waves can be present over a broad region of <jats:italic>L</jats:italic>=4–6 and 00–24MLT, with a higher occurrence in the region of <jats:italic>L</jats:italic>=5–6 and 06–19MLT. The electron phase space density exhibits a distinct ring distribution (<jats:italic>∂</jats:italic><jats:italic>f</jats:italic>/<jats:italic>∂</jats:italic><jats:italic>v</jats:italic><jats:sub>⊥</jats:sub> > 0) with the peak energy around a few kiloelectron volts. Both ECH wave events and the electron ring distributions are closely related and tend to be more distinct with increasing geomagnetic activity.</jats:p>
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英文
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Local Generation of High-Frequency Plasmaspheric Hiss Observed by Van Allen Probes
作者：
He, Zhaoguo* ;Chen, Lunjin* ;Liu, Xu;Zhu, Hui;Liu, Si;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2019年46(3):1141-1148 ISSN：0094-8276
通讯作者：
He, Zhaoguo;Chen, Lunjin
作者机构：
[He, Zhaoguo] Sun Yat Sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China.;[He, Zhaoguo] Univ Sci & Technol China, Chinese Acad Sci, Key Lab Geospace Environm, Hefei, Anhui, Peoples R China.;[He, Zhaoguo] CAS Ctr Excellence Comparat Planetol, Hefei, Anhui, Peoples R China.;[He, ZG; Chen, Lunjin; Liu, Xu; Zhu, Hui; Liu, Si; He, Zhaoguo] Univ Texas Dallas, Dept Phys, Richardson, TX 75083 USA.;[Gao, Zhonglei; Liu, Si] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
通讯机构：
[He, Zhaoguo] S;[He, Zhaoguo; He, ZG; Chen, LJ] U;[He, Zhaoguo] C;Sun Yat Sen Univ, Sch Atmospher Sci, Zhuhai, Peoples R China.;Univ Sci & Technol China, Chinese Acad Sci, Key Lab Geospace Environm, Hefei, Anhui, Peoples R China.
关键词：
plasmaspheric hiss;high frequency;local generation;substorm injection;electron
摘要：
The generation of a high-frequency plasmaspheric hiss (HFPH) wave observed by Van Allen Probes is studied in this letter for the first time. The wave has a moderate power spectral density (similar to 10(-6) nT(2)/Hz), with a frequency range extended from 2 to 10 kHz. The correlated observations of waves and particles indicate that HFPH is associated with the enhancement of electron flux during the substorm on 6 January 2014. Calculations of the wave linear growth rate driven by the fitted electron phase space density show that the electron distribution after the substorm onset is efficient for the HFPH generation. The energy of the contributing electrons is about 1-2 keV, which is consistent with the observation. These results support that the observed HFPH is likely to be generated locally inside the plasmasphere due to the instability of injected kiloelectron volt electrons.
语种：
英文
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Global Occurrences of Auroral Kilometric Radiation Related to Suprathermal Electrons in Radiation Belts
作者：
Zhao, Wanli;Liu, Si;Zhang, Sai;Zhou, Qinghua;Yang, Chang;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2019年46(13):7230-7236 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Zhao, Wanli; Yang, Chang; Zhang, Sai; Xiao, Fuliang; Gao, Zhonglei; Liu, Si; Zhou, Qinghua; He, Yihua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Zhao, Wanli; Xiao, Fuliang] Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha, Hunan, Peoples R China.;[Zhao, Wanli; Xiao, Fuliang] Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Higher Educ Key Lab Modeling & Monitor, Changsha, Hunan, Peoples R China.;Changsha Univ Sci & Technol, Hunan Prov Key Lab Flexible Elect Mat Genome Engn, Changsha, Hunan, Peoples R China.
关键词：
auroral kilometric radiation;suprathermal electron flux enhancements;global occurrence;radiation belt
摘要：
Auroral kilometric radiation (AKR) can potentially produce serious damage to space-borne systems by accelerating trapped radiation belt electrons to relativistic energies. Here we examine the global occurrences of AKR emissions in radiation belts based on Van Allen Probes observations from 1 October 2012 to 31 December 2016. The statistical results (1,848 events in total) show that AKR covers a broad region of L=3–6.5 and 00–24 magnetic local time (MLT), with a higher occurrence on the nightside (20–24 MLT and 00–04 MLT) within L=5–6.5. All the AKR events are observed to be accompanied with suprathermal (∼1keV) electron flux enhancements. During active geomagnetic periods, both AKR occurrences and electron injections tend to be more distinct, and AKR emission extends to the dayside. The current study shows that AKR emissions from the remote sources are closely associated with electron injections. © 2019. American Geophysical Union. All Rights Reserved.
语种：
英文
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Quantifying Extremely Rapid Flux Enhancements of Radiation Belt Relativistic Electrons Associated With Radial Diffusion
作者：
Liu, Si;Yan, Qi;Yang, Chang;Zhou, Qinghua;He, Zhaoguo;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2018年45(3):1262-1270 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Xiao, Fuliang; Gao, Zhonglei; Liu, Si; Zhou, Qinghua; He, Yihua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Liu, Si; He, Zhaoguo] Univ Texas Dallas, Dept Phys, William B Hanson Ctr Space Sci, Richardson, TX 75083 USA.;[Yan, Qi] Macau Univ Sci & Technol, Lunar & Planetary Sci Lab, Macau, Peoples R China.;[He, Zhaoguo] Harbin Inst Technol, Shenzhen Grad Sch, Shenzhen, Peoples R China.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
关键词：
radial diffusion;chorus-driven acceleration;radiation belt;Van Allen Probes;THEMIS
摘要：
Previous studies have revealed a typical picture that seed electrons are transported inward under the drive of radial diffusion and then accelerated via chorus to relativistic energies. Here we show a potentially different process during the 2–3 October 2013 storm when Van Allen Probes observed extremely rapid (by about 50 times in 2h) flux enhancements of relativistic (1.8–3.4MeV) electrons but without distinct chorus at lower L-shells. Meanwhile, Time History of Events and Macroscale Interactions during Substorms satellites simultaneously measured enhanced chorus and fluxes of energetic (∼100–300keV) seed electrons at higher L-shells. Numerical calculations show that chorus can efficiently accelerate seed electrons at L ∼ 8.3. Then radial diffusion further increased the phase space density of relativistic electrons throughout the outer radiation belts, with a remarkable agreement with the observation in magnitude and timescale. The current results provide a different physical scenario on the interplay between radial diffusion and local acceleration in outer radiation belt. ©2018. American Geophysical Union. All Rights Reserved.
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英文
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Examining Wave Vector and Minimum Cyclotron Resonant Electron Energy of EMIC Waves With Magnetospheric Multiscale Mission
作者：
Liu, Si;Zhang, Jian;Chen, Lunjin* ;Zhu, Hui;He, Zhaoguo
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2018年45(19):10,138-10,149 ISSN：0094-8276
通讯作者：
Chen, Lunjin
作者机构：
[Zhang, Jian; Liu, Si] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Chen, Lunjin; Zhu, Hui; Liu, Si; He, Zhaoguo] Univ Texas Dallas, Dept Phys, William B Hanson Ctr Space Sci, Richardson, TX 75083 USA.;[He, Zhaoguo] Harbin Inst Technol, Shenzhen Grad Sch, Sch Mech Engn & Automat, Shenzhen, Peoples R China.
通讯机构：
[Chen, Lunjin] U;Univ Texas Dallas, Dept Phys, William B Hanson Ctr Space Sci, Richardson, TX 75083 USA.
关键词：
EMIC waves;minimum resonant electron energy;wave vector;MMS;phase differencing
摘要：
Wave number vectors k and minimum cyclotron resonant electron energies Emin of electromagnetic ion cyclotron (EMIC) waves are analyzed via the phase differencing technique by using Magnetospheric Multiscale Mission data. It is demonstrated that the phase differencing method provides an estimate of the dominant wave number when finite k spectrum broadenings occur. A case study is conducted for the EMIC event on 20 November 2015, showing remarkable agreements with spectral analysis in wave propagation directions. We find that obtained wave vectors, roughly agreeing with the validity of cold plasma theory, might significantly vary from wave packet to wave packet. Numerical calculations indicate that Emin can range from 0.5 to tens of MeV, suggesting that EMIC waves can effectively interact with those relativistic electrons. This study enriches our understanding of the applicability of phase differencing. It further supports that EMIC waves can be responsible for the loss of electrons with an extremely broad energy range in the magnetosphere. ©2018. American Geophysical Union. All Rights Reserved.
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英文
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Generation of Lower L Shell Dayside Chorus by Energetic Electrons From the Plasma Sheet
作者：
He, Yihua* ;Xiao, Fuliang* ;Su, Zhenpeng;Zheng, Huinan;Yang, Chang;...
期刊：
JOURNAL OF GEOPHYSICAL RESEARCH: SPACE PHYSICS ,2018年123(10):8109-8121 ISSN：2169-9380
通讯作者：
He, Yihua;Xiao, Fuliang
作者机构：
[Su, Zhenpeng; Zheng, Huinan; He, Yihua] Univ Sci & Technol China, Dept Geophys & Planetary Sci, CAS Key Lab Geospace Environm, Hefei, Anhui, Peoples R China.;[Yang, Chang; Xiao, Fuliang; He, Yihua; Liu, Si; Zhou, Qinghua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Su, Zhenpeng; Zheng, Huinan; He, Yihua] Univ Sci & Technol China, Collaborat Innovat Ctr Astronaut Sci & Technol, Hefei, Anhui, Peoples R China.;[He, Yihua] Univ Sci & Technol China, Sch Earth & Space Sci, Mengcheng Natl Geophys Observ, Hefei, Anhui, Peoples R China.
通讯机构：
[He, Yihua] U;[He, YH; Xiao, FL] C;Univ Sci & Technol China, Dept Geophys & Planetary Sci, CAS Key Lab Geospace Environm, Hefei, Anhui, Peoples R China.;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;Univ Sci & Technol China, Collaborat Innovat Ctr Astronaut Sci & Technol, Hefei, Anhui, Peoples R China.
关键词：
Van Allen Probes;dayside chorus generation;radiation belt;wave-particle interaction
摘要：
Currently, the generation mechanism for the lower L shell dayside chorus has still remained an open question. Here we report two storm events: 6–7 March 2016 and 20–21 January 2016, when Van Allen Probes observed enhanced dayside chorus with lower and higher wave normal angles (the angles between the wave vector and the geomagnetic field) in the region of L = 3.5–6.3 and MLT = 5.6–13.5. Hot and energetic (∼ 1–100 keV) electrons displayed enhancements in fluxes and anisotropy when they were injected from the plasma sheet and drifted from midnight through dawn toward the dayside. Calculations of chorus local growth rates under different waves normal angles show that the upper cutoff and peak wave frequencies display similar patterns to the observations. Chorus growth rates maximize for the parallel propagation and drop with increasing wave normal angles. The current results confirm that the observed lower L shell dayside chorus can be excited by anisotropic electrons originating from the plasma sheet in drifting from the nightside to the dayside.
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英文
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Storm Time Evolution of Outer Radiation Belt Relativistic Electrons by a Nearly Continuous Distribution of Chorus
作者：
Yang, Chang;Xiao, Fuliang* ;He, Yihua;Liu, Si;Zhou, Qinghua;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2018年45(5):2159-2167 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Zhao, Wanli; Yang, Chang; Xiao, Fuliang; He, Yihua; Liu, Si; Zhou, Qinghua; Guo, Mingyue] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Yang, Chang; He, Yihua] Univ Sci & Technol China, Dept Geophys & Planetary Sci, Hefei, Anhui, Peoples R China.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
关键词：
outer radiation belt;whistler mode chorus wave;energetic electron;wave-particle interaction;geomagnetic storm
摘要：
During the 13–14 November 2012 storm, Van Allen Probe A simultaneously observed a 10 h period of enhanced chorus (including quasi-parallel and oblique propagation components) and relativistic electron fluxes over a broad range of L = 3–6 and magnetic local time = 2–10 within a complete orbit cycle. By adopting a Gaussian fit to the observed wave spectra, we obtain the wave parameters and calculate the bounce-averaged diffusion coefficients. We solve the Fokker-Planck diffusion equation to simulate flux evolutions of relativistic (1.8–4.2 MeV) electrons during two intervals when Probe A passed the location L = 4.3 along its orbit. The simulating results show that chorus with combined quasi-parallel and oblique components can produce a more pronounced flux enhancement in the pitch angle range ∼45°–80°, consistent well with the observation. The current results provide the first evidence on how relativistic electron fluxes vary under the drive of almost continuously distributed chorus with both quasi-parallel and oblique components within a complete orbit of Van Allen Probe.<br/> ©2018. American Geophysical Union. All Rights Reserved.
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英文
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Flexible polymer solar cells based on Ag metallic grids and functional reduced graphene oxide composite electrode
作者：
Zheng, Qiao;Cheng, Shuying;Jia, Hongjie* ;Zhang, Hong;Liu, Si;...
期刊：
Journal of Physics D: Applied Physics ,2017年50(41):415101 ISSN：0022-3727
通讯作者：
Jia, Hongjie
作者机构：
[Zhou, Haifang; Cheng, Shuying; Yu, Jinling; Zheng, Qiao; Zhang, Hong; Jia, Hongjie; Lai, Yunfeng] Fuzhou Univ, Coll Phys & Informat Engn, Fuzhou 350116, Fujian, Peoples R China.;[Zhou, Haifang; Cheng, Shuying; Yu, Jinling; Zheng, Qiao; Zhang, Hong; Jia, Hongjie; Lai, Yunfeng] Fuzhou Univ, Inst Micronano Devices & Solar Cells, Fuzhou 350116, Fujian, Peoples R China.;[Cheng, Shuying; Zheng, Qiao; Zhang, Hong; Jia, Hongjie; Lai, Yunfeng] Jiangsu Collaborat Innovat Ctr Photovolta Sci & E, Changzhou 213164, Jiangsu, Peoples R China.;[Zhou, Haifang; Yu, Jinling; Zheng, Qiao] Fuzhou Univ, Fujian Key Lab New Energy Generat & Power Convers, Fuzhou 350116, Fujian, Peoples R China.;[Liu, Si] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Jia, Hongjie] F;[Jia, Hongjie] J;Fuzhou Univ, Coll Phys & Informat Engn, Fuzhou 350116, Fujian, Peoples R China.;Fuzhou Univ, Inst Micronano Devices & Solar Cells, Fuzhou 350116, Fujian, Peoples R China.;Jiangsu Collaborat Innovat Ctr Photovolta Sci & E, Changzhou 213164, Jiangsu, Peoples R China.
关键词：
Electrodes;Graphene;Photoelectricity;Polymer solar cells;Polymers;Silver;Flexible electrodes;ITO free;Ito substrates;Metallic grid;Photoelectric property;Polymer solar cell (PSCs);Power conversion efficiencies;Reduced graphene oxides;Solar cells
摘要：
By combining the appropriate Ag metallic grids with a thin functional reduced graphene oxide (MGs/F-rGO) film, a suitable photoelectric flexible electrode of the polymer solar cells (PSCs) is obtained. The conductivity and transmission of the MGs/F-rGO composited films can be improved by HNO3 modified. The optimized sheet resistance and transmission of the flexible electrode achieve to 25 Ω □-1 and 83% at 550 nm wavelength. Flexible PSCs with the MGs/F-rGO electrode show 5.63% power conversion efficiency. The photoelectric properties of the MGs/F-rGO film comparable with that of ITO substrates guarantee a high short current and an enhanced PCE of the solar cells. This method provides a feasible way for fabricating low-cost and flexible PSCs. © 2017 IOP Publishing Ltd.
语种：
英文
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Generation of extremely low frequency chorus in Van Allen radiation belts
作者：
Xiao, Fuliang* ;Liu, Si;Tao, Xin;Su, Zhenpeng;Zhou, Qinghua;...
期刊：
JOURNAL OF GEOPHYSICAL RESEARCH: SPACE PHYSICS ,2017年122(3):3201-3211 ISSN：2169-9380
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Liu, Si; He, Yihua; Xiao, Fuliang; Zhou, Qinghua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Tao, Xin; Su, Zhenpeng; Gao, Zhonglei] Univ Sci & Technol China, Chinese Acad Sci, Key Lab Basic Plasma Phys, Hefei, Peoples R China.;[He, Zhaoguo] Harbin Inst Technol, Shenzhen Grad Sch, Shenzhen, Peoples R China.;[Baker, D. N.] Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.;[Spence, H. E.] Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
关键词：
ELF chorus waves;wave-particle interaction;relativistic distribution;RBSP results
摘要：
Recent studies have shown that chorus can efficiently accelerate the outer radiation belt electrons to relativistic energies. Chorus, previously often observed above 0.1 equatorial electron gyrofrequency fce, was generated by energetic electrons originating from Earth's plasma sheet. Chorus below 0.1 fce has seldom been reported until the recent data from Van Allen Probes, but its origin has not been revealed so far. Because electron resonant energy can approach the relativistic level at extremely low frequency, relativistic effects should be considered in the formula for whistler mode wave growth rate. Here we report high-resolution observations during the 14 October 2014 small storm and firstly demonstrate, using a fully relativistic simulation, that electrons with the high-energy tail population and relativistic pitch angle anisotropy can provide free energy sufficient for generating chorus below 0.1 fce. The simulated wave growth displays a very similar pattern to the observations. The current results can be applied to Jupiter, Saturn, and other magnetized planets.
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英文
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细小线材扫描式激光测径仪
作者：
周志;刘斯;吴定祥;曾凯;龚金成;...
期刊：
测控技术 ,2017年36(1):96-99 ISSN：1000-8829
作者机构：
长沙理工大学物理与电子科学学院, 近地空间电磁环境监测与建模湖南省普通高校重点实验室, 湖南, 长沙, 410114;长沙亿旭机电科技有限公司, 湖南, 长沙, 410000;长沙湘鸿仪器机械制造有限责任公司, 湖南, 长沙, 410002;常德市电子技术研究所, 湖南, 常德, 415000;[周志; 刘斯; 唐立军] 长沙理工大学物理与电子科学学院, 近地空间电磁环境监测与建模湖南省普通高校重点实验室, 湖南, 长沙, 410114
关键词：
细小线材;激光测径;漆包线
摘要：
针对漆包线等相关非透明细小线材快速实时监测问题开展研究,设计实现了扫描式激光测径仪,该测径仪应用“标准棒法”光学测量系统,采用分组策略的方法,以FPGA + ARM为控制器,来实现快速实时监测。测试结果表明,测径仪测量范围为0.1 ~1 mm,示值误差不大于±0.0005 mm,并且具有通过网络串口在PC机实时显示测量数据的功能。
语种：
中文
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磁通门磁强计感应回路的稳态解析模型
作者：
刘斯;曹大平;唐立军;何兆国
期刊：
传感技术学报 ,2017年30(4):555-559 ISSN：1004-1699
通讯作者：
Liu, S.
作者机构：
[唐立军; 刘斯] School of Physical and Electronic Sciences, Changsha University of Science and Technology, Changsha, 410114, China;[曹大平] School of Physics and Technology, Wuhan University, Wuhan, 430072, China;[何兆国] Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, Guangdong 518055, China
通讯机构：
[Liu, S.] S;School of Physical and Electronic Sciences, China
关键词：
磁通门;磁传感器;参数放大效应;灵敏度;稳定性
摘要：
针对磁通门磁强计感应回路中调谐电容对灵敏度的影响,提出了磁通门感应回路的分段解析稳态模型,计算了不同调谐电容值时的感应电流波形及峰-峰值。计算与实验的对比表明,感应波形之间相关系数均大于0.98,峰-峰值p平均计算误差小于3%。调谐电容在±8%内变化时,引起的磁通门灵敏度变化为大于37%。本文提供的磁通门感应回路稳态模型能够用于精确描述输出电流性质,为研究磁通门系统的温度稳定性提供分析和参考。
语种：
中文
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Generation of lower and upper bands of electrostatic electron cyclotron harmonic waves in the Van Allen radiation belts
作者：
Zhou, Qinghua;Xiao, Fuliang* ;Yang, Chang;Liu, Si;He, Yihua;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2017年44(11):5251-5258 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Xiao, Fuliang; Zhou, Qinghua; Liu, Si; He, Yihua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Baker, D. N.] Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80309 USA.;[Spence, H. E.] Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA.;[Reeves, G. D.] Los Alamos Natl Lab, Space Sci & Applicat Grp, Los Alamos, NM USA.;[Funsten, H. O.] Los Alamos Natl Lab, ISR Div, Los Alamos, NM USA.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
关键词：
ECH waves;wave-particle interaction;RBSP results
摘要：
Electrostatic electron cyclotron harmonic (ECH) waves generated by the electron loss cone distribution can produce efficient scattering loss of plasma sheet electrons, which has a significant effect on the dynamics in the outer magnetosphere. Here we report two ECH emission events around the same location L≈ 5.7–5.8, MLT ≈ 12 from Van Allen Probes on 11 February (event A) and 9 January 2014 (event B), respectively. The spectrum of ECH waves was centered at the lower half of the harmonic bands during event A, but the upper half during event B. The observed electron phase space density in both events is fitted by the subtracted bi-Maxwellian distribution, and the fitting functions are used to evaluate the local growth rates of ECH waves based on a linear theory for homogeneous plasmas. ECH waves are excited by the loss cone instability of 50 eV–1 keV electrons in the lower half of harmonic bands in the low-density plasmasphere in event A, and 1–10 keV electrons in the upper half of harmonic bands in a relatively high-density region in event B. The current results successfully explain observations and provide a first direct evidence on how ECH waves are generated in the lower and upper half of harmonic frequency bands.
语种：
英文
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Evolution of chorus emissions into plasmaspheric hiss observed by Van Allen Probes
作者：
Zhou, Qinghua;Xiao, Fuliang* ;Yang, Chang;Liu, Si;He, Yihua;...
期刊：
JOURNAL OF GEOPHYSICAL RESEARCH: SPACE PHYSICS ,2016年121(5):4518-4529 ISSN：2169-9380
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Xiao, Fuliang; Zhou, Qinghua; Liu, Si; He, Yihua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Wygant, J. R.] Univ Minnesota, Sch Phys & Astron, Minneapolis, MN USA.;[Baker, D. N.] Univ Colorado Boulder, Lab Atmospher & Space Phys, Boulder, CO USA.;[Spence, H. E.] Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA.;[Reeves, G. D.] Los Alamos Natl Lab, Space Sci & Applicat Grp, Los Alamos, NM USA.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
关键词：
plasmaspheric hiss;chorus waves;RBSP results
摘要：
The two classes of whistler mode waves (chorus and hiss) play different roles in the dynamics of radiation belt energetic electrons. Chorus can efficiently accelerate energetic electrons, and hiss is responsible for the loss of energetic electrons. Previous studies have proposed that chorus is the source of plasmaspheric hiss, but this still requires an observational confirmation because the previously observed chorus and hiss emissions were not in the same frequency range in the same time. Here we report simultaneous observations form Van Allen Probes that chorus and hiss emissions occurred in the same range ∼300–1500Hz with the peak wave power density about 10−5nT2/Hz during a weak storm on 3 July 2014. Chorus emissions propagate in a broad region outside the plasmapause. Meanwhile, hiss emissions are confined inside the plasmasphere, with a higher intensity and a broader area at a lower frequency. A sum of bi-Maxwellian distribution is used to model the observed anisotropic electron distributions and to evaluate the instability of waves. A three-dimensional ray tracing simulation shows that a portion of chorus emission outside the plasmasphere can propagate into the plasmasphere and evolve into plasmaspheric hiss. Moreover, hiss waves below 1kHz are more intense and propagate over a broader area than those above 1kHz, consistent with the observation. The current results can explain distributions of the observed hiss emission and provide a further support for the mechanism of evolution of chorus into hiss emissions. ©2016. American Geophysical Union. All Rights Reserved.
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英文
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Explaining occurrences of auroral kilometric radiation in Van Allen radiation belts
作者：
Xiao, Fuliang* ;Zhou, Qinghua;Su, Zhenpeng;He, Zhaoguo;Yang, Chang;...
期刊：
GEOPHYSICAL RESEARCH LETTERS ,2016年43(23):11,971-11,978 ISSN：0094-8276
通讯作者：
Xiao, Fuliang
作者机构：
[Yang, Chang; Xiao, Fuliang; Zhou, Qinghua; Liu, Si; He, Yihua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.;[Su, Zhenpeng; Gao, Zhonglei] Univ Sci & Technol China, Chinese Acad Sci, Key Lab Basic Plasma Phys, Hefei, Peoples R China.;[He, Zhaoguo] Shenzhen Grad Sch, Harbin Inst Technol, Shenzhen, Peoples R China.
通讯机构：
[Xiao, Fuliang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha, Hunan, Peoples R China.
关键词：
AKR emissions;ray tracing simulations;radiation belts;geomagnetic storms;satellite data
摘要：
Auroral kilometric radiation (AKR) is a strong terrestrial radio emission and dominates at higher latitudes because of reflection in vicinities of the source cavity and plasmapause. Recently, Van Allen Probes have observed occurrences of AKR emission in the equatorial region of Earth's radiation belts but its origin still remains an open question. Equatorial AKR can produce efficient acceleration of radiation belt electrons and is a risk to space weather. Here we report high-resolution observations during two small storm periods 4–6 April and 18–20 May 2013 and show, using a 3-D ray tracing simulation, that AKR can propagate downward all the way into the equatorial plane in the radiation belts under appropriate conditions. The simulated results can successfully explain the observed AKR's spatial distribution and frequency range, and the current results have a wide application to all other magnetized astrophysical objects in the universe. ©2016. American Geophysical Union. All Rights Reserved.
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英文
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Magnetospheric chorus wave instability induced by relativistic Kappa-type distributions
作者：
Yang QiWu;Yang Chang;He YiHua;Liu Si;Zhou QingHua;...
期刊：
中国科学:技术科学(英文版) ,2016年59(11):1739-1745 ISSN：1674-7321
通讯作者：
Xiao FuLiang
作者机构：
[Xiao FuLiang; Yang QiWu; Yang Chang; Liu Si; Zhou QingHua; He YiHua] Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Xiao FuLiang] C;Changsha Univ Sci & Technol, Sch Phys & Elect Sci, Changsha 410004, Hunan, Peoples R China.
关键词：
Kappa-type distribution;energetic electrons;wave-particle interaction;chorus wave instability
摘要：
We study the field-aligned propagating magnetospheric chorus wave instability using a fully relativistic wave growth formula, the previously developed relativistic Kappa-type (KT) distribution and the regular Kappa distribution of energetic electrons. We demonstrate that the peak growth rate using the nonrelativistic Kappa simulation is higher than that using either the relativistic KT or the Kappa simulation at/above 100 keV, because the significant relativistic effect yields a reduction in the relativistic anisotropy. The relativistic anisotropy A_(rel) basically decreases as the thermal parameter θ~2 increases, allowing the peak growth by relativistic KT or Kappa distribution to stay at the lower frequency region. The growth rates tend to increase with the loss-cone parameter l because the overall anisotropy increases. Moreover, at high energy ~1.0 MeV, both the growth rate and the upper cutoff frequency become smaller as l increases for the relativistic KT calculation because the significant relativistic effect reduces both the resonant anisotropy and the number of the hot electrons, which is in contrast to the relativistic and nonrelativistic Kappa distribution calculations because the less relativistic or non-relativistic effect enhances the resonant anisotropy as l increases. The above results can be applied to the whistler-mode wave instability in the outer radiation belts of the Earth, the Jovian inner magnetosphere and other astrophysical plasmas where relativistic electrons often exist.
语种：
英文
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