In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense...In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense large-scale traveling atmospheric disturbances(TADs)originating at high latitudes and propagating equatorward.Observations by TM02 captured the evolution of a TAD structure:An initial amplitude of~3.89×10^(-12)kg/m^(3)at hundred-kilometer scale subsequently intensified to 4.78×10^(-12)kg/m^(3),with the spatial extent expanding to the thousand-kilometer level.Significant hemispheric asymmetry was observed:the absolute density was higher predominantly in the northern hemisphere(TM02,TM06,TM07,TM11),whereas the difference in the relative density consistently showed greater enhancements in the southern hemisphere across all satellites,with the maximum north-south density differences exceeding 195%-640%above 60°latitude.In conjunction with SuperDARN(Super Dual Auroral Radar Network)observations,this striking hemispheric asymmetry can likely be attributed to disparities in plasma convection patterns between the two hemispheres.Furthermore,density perturbation characteristics exhibited strong local time(LT)dependence:Near noon(~10.7 LT,TM02 descending),the northern hemisphere onset preceded the southern onset.Conversely,near dusk(~17.6 LT,TM15 descending),the southern onset led the northern onset by approximately 3 hours.Ascending orbits(TM02,TM06,TM07,TM15)typically yielded larger global density enhancements compared with smaller southern-confined enhancements during descending orbits.Satellite TM11 showed comparable perturbations in both ascending and descending orbits.By leveraging its unique orbital architecture,the TianMu-1 constellation enables global near-simultaneous multi-LT sampling,providing a robust data foundation for both scientific research and engineering applications.展开更多
Electrons in the energy range of 10–100 keV are important energetic particle components in the magnetosphere,and they play a key role in many physical processes in the magnetosphere.However,many scientific questions ...Electrons in the energy range of 10–100 keV are important energetic particle components in the magnetosphere,and they play a key role in many physical processes in the magnetosphere.However,many scientific questions about these processes are still unanswered.High spatiotemporal and energy-resolution imaging detection of 10–100 keV electrons is of great significance for solving these scientific problems.The traditional space particle detection technology cannot effectively detect the medium-energy electrons in this energy range.In this project,we propose combining low-noise particle detection technology with pinhole imaging technology to achieve high-resolution imaging detection of 10–100 keV medium-energy electrons in the magnetosphere,and at the same time achieve miniaturization(≤3.2 kg and size of 150×150×170 mm)and low power consumption(≤5 W)of the instrument,which can be used for space physics research and space weather applications in the future.展开更多
Global-and meso-scale dipolarizations are well-known features of Earth’s magnetosphere,but their coupling remains poorly understood.Here,using a new approach that combines two-dimentional(2D)ionospheric field-aligned...Global-and meso-scale dipolarizations are well-known features of Earth’s magnetosphere,but their coupling remains poorly understood.Here,using a new approach that combines two-dimentional(2D)ionospheric field-aligned current(FAC)maps with coordinated observations from a network of magnetospheric satellites,we directly show that individual global-scale dipolarizations can expand from the nightside to,or even into,the dayside.These expansions are enduring(20–30 minutes),slow(2–4 deg/min),and global in extent(up to 12 h in local time),consistent with previous statistical inferences but now explicitly observed.The expanding FACs form a two-sheet current system as described by the Boström II model.In contrast,meso-scale dipolarizations are bursty(a few minutes),fast(several tens deg/min),and localized(several hours in local time),as evidenced by auroral expansions and satellite data.They are associated with the line-current system as described by the Boström I model(i.e.,the substorm current wedge).Notably,meso-scale dipolarizations often emerge near the expanding edge of a global-scale dipolarization,suggesting a dynamic coupling between the two scales.These observations provide a complementary scenario to the simulation-based interpretation that global-scale dipolarizations result from the accumulation of meso-scale dipolarizations.Here,meso-scale dipolarizations appear far less frequently than in simulations and occur around the edge of global-scale dipolarizations.This result implies that meso-scale dipolarizations may be sporadically triggered during the azimuthal expansion of global-scale dipolarizations.展开更多
Auroral kilometric radiation(AKR),a fundamental plasma emission in Earth's magnetosphere,exhibits three characteristic modes:the right-handed extraordinary(R-X),left-handed ordinary(L-O)and left-handed extraordina...Auroral kilometric radiation(AKR),a fundamental plasma emission in Earth's magnetosphere,exhibits three characteristic modes:the right-handed extraordinary(R-X),left-handed ordinary(L-O)and left-handed extraordinary(L-X)modes.The role of AKR in magnetosphere−ionosphere−atmosphere coupling depends sensitively on its wave mode.While previous studies have primarily focused on the dominant R-X mode,we present the first systematic identification of all three modes using a practical polarization analysis method based on Arase satellite observations.This method employs a spin-axis-relative Ratio:when the satellite's spin axis aligns with the background magnetic field,a positive(negative)Ratio indicates the right-handed(left-handed)polarization,with reversal under anti-parallel conditions.Combined polarization-frequency analysis reveals that R-X,L-O,and L-X modes can exist in both dayside and nightside regions,with power spectral densities up to 10^(-6)mV^(2)m^(-2)Hz^(-1).This study resolves long-standing ambiguities in AKR mode classification and has implications for understanding AKR-induced electron dynamics.展开更多
本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证...本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证明,磁暴环电流增强期间环电流的变化速度,不仅取决于行星际磁场南向分量和太阳风的速度,还取决于太阳风的动压,而且太阳风的动压起着非常重要的作用.研究还发现,采用Burton et al.(1975)方程和O′Brien,McPherron (2000a)方程估算得到的2000年10月5日的两次地磁活动的强度远低于实际的观测值.展开更多
基金the National Space Science Center (NSSC) of the Chinese Academy of Sciences for full support of this research workfunded by the Tian Mu-1 Constellation Atmospheric Density Detector (Grant No. E3C1162110)
文摘In this study,we analyze the impact of the May 2024 geomagnetic storm on the thermospheric mass density by using TianMu-1 constellation satellite(TM02,TM06,TM07,TM11,TM15)observations.These observations reveal intense large-scale traveling atmospheric disturbances(TADs)originating at high latitudes and propagating equatorward.Observations by TM02 captured the evolution of a TAD structure:An initial amplitude of~3.89×10^(-12)kg/m^(3)at hundred-kilometer scale subsequently intensified to 4.78×10^(-12)kg/m^(3),with the spatial extent expanding to the thousand-kilometer level.Significant hemispheric asymmetry was observed:the absolute density was higher predominantly in the northern hemisphere(TM02,TM06,TM07,TM11),whereas the difference in the relative density consistently showed greater enhancements in the southern hemisphere across all satellites,with the maximum north-south density differences exceeding 195%-640%above 60°latitude.In conjunction with SuperDARN(Super Dual Auroral Radar Network)observations,this striking hemispheric asymmetry can likely be attributed to disparities in plasma convection patterns between the two hemispheres.Furthermore,density perturbation characteristics exhibited strong local time(LT)dependence:Near noon(~10.7 LT,TM02 descending),the northern hemisphere onset preceded the southern onset.Conversely,near dusk(~17.6 LT,TM15 descending),the southern onset led the northern onset by approximately 3 hours.Ascending orbits(TM02,TM06,TM07,TM15)typically yielded larger global density enhancements compared with smaller southern-confined enhancements during descending orbits.Satellite TM11 showed comparable perturbations in both ascending and descending orbits.By leveraging its unique orbital architecture,the TianMu-1 constellation enables global near-simultaneous multi-LT sampling,providing a robust data foundation for both scientific research and engineering applications.
基金supported by the National Natural Science Foundation of China(Grant No.42274225)the International Science and Technology Cooperation Project of the Ningbo Key R&D Program(Grant No.2024H031).
文摘Electrons in the energy range of 10–100 keV are important energetic particle components in the magnetosphere,and they play a key role in many physical processes in the magnetosphere.However,many scientific questions about these processes are still unanswered.High spatiotemporal and energy-resolution imaging detection of 10–100 keV electrons is of great significance for solving these scientific problems.The traditional space particle detection technology cannot effectively detect the medium-energy electrons in this energy range.In this project,we propose combining low-noise particle detection technology with pinhole imaging technology to achieve high-resolution imaging detection of 10–100 keV medium-energy electrons in the magnetosphere,and at the same time achieve miniaturization(≤3.2 kg and size of 150×150×170 mm)and low power consumption(≤5 W)of the instrument,which can be used for space physics research and space weather applications in the future.
基金NASA(National Aeronautics and Space Administration)grant 81NSSC19K0306NASA prime contract NAS5-01072+6 种基金AFOSR(Air Force Office of Scientific Research)grant FA9559-16-1-0364NSF(National Science Foundation)grant AGS-2055192NASA grants 80NSSC20K1314,80NSSC20K1316,and 80NSSC21K1407NASA Contract NAS5-02099NASA grants:80NSSC18K1220 and 80NSSC18K0570NASA contracts 80GSFC17C0018,and NAS5-02099NASA award 80NSSC18K122。
文摘Global-and meso-scale dipolarizations are well-known features of Earth’s magnetosphere,but their coupling remains poorly understood.Here,using a new approach that combines two-dimentional(2D)ionospheric field-aligned current(FAC)maps with coordinated observations from a network of magnetospheric satellites,we directly show that individual global-scale dipolarizations can expand from the nightside to,or even into,the dayside.These expansions are enduring(20–30 minutes),slow(2–4 deg/min),and global in extent(up to 12 h in local time),consistent with previous statistical inferences but now explicitly observed.The expanding FACs form a two-sheet current system as described by the Boström II model.In contrast,meso-scale dipolarizations are bursty(a few minutes),fast(several tens deg/min),and localized(several hours in local time),as evidenced by auroral expansions and satellite data.They are associated with the line-current system as described by the Boström I model(i.e.,the substorm current wedge).Notably,meso-scale dipolarizations often emerge near the expanding edge of a global-scale dipolarization,suggesting a dynamic coupling between the two scales.These observations provide a complementary scenario to the simulation-based interpretation that global-scale dipolarizations result from the accumulation of meso-scale dipolarizations.Here,meso-scale dipolarizations appear far less frequently than in simulations and occur around the edge of global-scale dipolarizations.This result implies that meso-scale dipolarizations may be sporadically triggered during the azimuthal expansion of global-scale dipolarizations.
基金supported by the National Natural Science Foundation of China(Grants 42374215,42230209,42374199,42304183,42422406,42174185,72061147004 and 72342001)the Science and Technology Development Fund,Macao SAR(File no.0042/2024/RIA1 and 0008/2024/AKP)+1 种基金the Natural Science Foundation of Hunan Province(Grant 2023JJ20038)the Research Project of Science and Technology of Hunan Province(2025JJ10009,2022RC4025,2025QK1004,2023JJ50312,2023JJ50010 and 2024RC9012).
文摘Auroral kilometric radiation(AKR),a fundamental plasma emission in Earth's magnetosphere,exhibits three characteristic modes:the right-handed extraordinary(R-X),left-handed ordinary(L-O)and left-handed extraordinary(L-X)modes.The role of AKR in magnetosphere−ionosphere−atmosphere coupling depends sensitively on its wave mode.While previous studies have primarily focused on the dominant R-X mode,we present the first systematic identification of all three modes using a practical polarization analysis method based on Arase satellite observations.This method employs a spin-axis-relative Ratio:when the satellite's spin axis aligns with the background magnetic field,a positive(negative)Ratio indicates the right-handed(left-handed)polarization,with reversal under anti-parallel conditions.Combined polarization-frequency analysis reveals that R-X,L-O,and L-X modes can exist in both dayside and nightside regions,with power spectral densities up to 10^(-6)mV^(2)m^(-2)Hz^(-1).This study resolves long-standing ambiguities in AKR mode classification and has implications for understanding AKR-induced electron dynamics.
文摘本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证明,磁暴环电流增强期间环电流的变化速度,不仅取决于行星际磁场南向分量和太阳风的速度,还取决于太阳风的动压,而且太阳风的动压起着非常重要的作用.研究还发现,采用Burton et al.(1975)方程和O′Brien,McPherron (2000a)方程估算得到的2000年10月5日的两次地磁活动的强度远低于实际的观测值.
