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Radiation belt electron wisp inside South Atlantic Anomaly due to terrestrial VLF transmitter observed by MSS-1

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science China Earth sciences 2025年第2期68卷 538-548页

作者： Yixin SUN Ying LIU Qiugang ZONG Yixin HAO Hong ZOU Yuguang YE Institute of space Physics and applied Technology Peking UniversityBeijing 100871China State Key Laboratory of Lunar and Planetary science Macao University of Science and TechnologyMacao 999078China Max Planck Institute for Solar System research Goettingen 37077Germany

The South Atlantic Anomaly represents a region within near-Earth space characterized by a significantly weaker geomagnetic field and a higher flux of energetic particles compared to other areas. It is a space weather hazards to Low-EarthOrbit satellites. There has been evidence that the Very Low Frequency(VLF) waves from the powerful ground VLF radio transmitter in Australia, known as NWC, have the capacity to scatter energetic electrons' pitch angle in the inner radiation *** scattering directs electrons into the drift loss cone, forms a “wisp”, characterized by its peak intensity outside the South Atlantic Anomaly(SAA), and a “rift” exhibiting minimal intensity within SAA. Our findings mark the initial observation of a“wisp” precipitation, an unusual occurrence with peak intensity detected inside the SAA, observed via the Macao science Satellite-1. Enabled by the Medium-energy Electron Spectrometer onboard Macao science Satellite-1, we were able to comprehensively measure the full pitch angle distribution at Low-Earth-Orbit. This allowed us to attribute the “wisp” within the anomaly to a specific pitch angle range just outside the drift loss cone, a measurement unattainable by previous satellites. This“wisp” occurrence aligns with previous model predictions, despite being overlooked. Moreover, we distinguished between the trapped and precipitating electron populations. Directly derived from the ratio of these populations, our analysis revealed that approximately 2%-5% of trapped electrons will be lost in this specific wisp due to the influence of the ground VLF *** results not only complement existing evidence of energetic electron pitch angle scattering facilitated by the ground VLF transmitter but also offer a quantitative estimation of its impact.

关键词： South Atlantic Anomaly Radiation belts Electrons precipitation VLF transmitter Wave-particle interaction

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Simulations of electron zebra stripes in the inner radiation belt using a composite empirical electric field model

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science China Earth sciences 2025年第1期68卷 27-38页

作者： Ziyang WANG Ying LIU Qiugang ZONG Hong ZOU Yuguang YE Xuzhi ZHOU Chao YUE Shan WANG Institute of space Physics and applied Technology Peking UniversityBeijing100871China State Key Laboratory of Lunar and Planetary science Macao University of Science and TechnologyMacao999078China

The phenomenon termed“zebra stripes”manifests as regular patterns in the energy-space(L shell)spectrum of energetic electrons(ranging from tens to hundreds ke V)within the inner radiation *** structures exhibit drift-periodic behavior and commonly arise from large-scale electric field perturbations near the substorm *** this study,we introduce a composite electric field model and replicate the formation,structure,and evolution of zebra stripes using a bounce-averaged test particle code under this electric field ***-resolution measurements of energetic electrons obtained from the Van Allen Probes and the recently launched Macao science Satellites-1 are used as initial conditions and served to validate our test particle *** analyses between observed data and simulations demonstrate our test particle method's efficacy in capturing zebra stripes'general ***,the composite model proves capable of reproducing realistic variations in the electric field within the inner radiation belt to a certain ***,subtle differences emerge in the flux strength and the positions of *** disparities primarily stem from limitations inherent in the electric field model and the initial conditions of the *** that the model represents an average case,it is conceivable that real-world scenarios may deviate from the average,thereby introducing variations in the observed phenomena.

关键词： Zebra stripes Inner radiation belt Large-scale electric fields Van Allen Probes Macao science Satellite

The low-latitude sodium layer:comparative data from lidar observations at Hainan,China and São Paulo,Brazil

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Earth and Planetary Physics 2025年第1期9卷 39-53页

作者： Fang Wu Jing Jiao GuoTao Yang LiFang Du ZhengKuan Liu HaoRan Zheng JiXin Guo ShaoHua Gong YaJun Zhu State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Hainan National Field science Observation and research Observatory for space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China University of Chinese Academy of sciences Beijing 100049China China-Brazil Joint Laboratory for space Weather NSSC/INPESão Josédos Campos 12227-010Brazil School of Physics and Electronics Engineering Hainan Normal UniversityHaikou 571158China

Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude *** sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s *** paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the *** low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in ***,maximal Na density over Brazil is greater than that over *** variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before *** variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain *** suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.

关键词： metallic sodium layer seasonal variation nocturnal variation lidar

Revealing the difference of Stark tuning rate between interface and bulk by surface-enhanced infrared absorption spectroscopy

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Chinese Chemical Letters 2025年第2期36卷 461-464页

作者： Manyu Zhu Fei Liang Lie Wu Zihao Li Chen Wang Shule Liu Xiue Jiang State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied ChemistryChinese Academy of Sciences School of applied Chemistry and Engineering University of Science and Technology of China School of Materials science and Engineering Sun Yat-sen University research center for Analytical science College of ChemistryNankai University

Revealing the factors that affect the vibrational frequency of Stark probe at interface is a pre-requirement for evaluating the absolute interfacial electric *** using surface-enhanced infrared absorption(SEIRA) spectroscopy,attenuated total reflection (ATR) spectroscopy and molecular dynamics (MD),we reveal the assembled C≡N at gold nanofilm exhibits a reduced Stark tuning rate (STR) referring to the vibrational frequency shift in response to electric field comparing with the bulk which was regulated by the electron transfer between S and *** findings lead to a deeper understanding of the vibrational Stark effect at the interface and provide guidance for improving the interface electric field theory.

关键词： Attenuated total reflection spectroscopy Cyano group Stark tuning rate Surface-enhanced infrared spectroscopy Vibrational stark effect

A Multi-faceted View of the X-Ray Spectral Variability in Seyfert Galaxy Ark 120

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research in Astronomy and Astrophysics 2025年第1期25卷 228-239页

作者： Lu-Xin Ren Jun-Xian Wang Jia-Lai Kang CAS Key Laboratory for research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China School of Astronomy and space science University of Science and Technology of China

Utilizing a range of techniques including multi-band light curves,softness ratio analysis,structure functions,rms spectra,cross-correlation functions,and ratios of spectra from different intervals,we present a comprehensive study of the complex X-ray spectral variability in Seyfert 1 galaxy Ark 120,through re-analyzing its six XMM-Newton observations taken between 2003 and *** find a clear“softer-when-brighter”trend in the 2–10 ke V power-law component over long timescales,with this trend being timescale dependent,as it is much weaker on shorter timescales,similar to that previously detected in NGC ***,a rare“harder-when-brighter”trend is observed during one exposure,indicating dynamic changes in the spectral variability behavior of the power-law *** exceptional exposure,with the spectral variability indeed marked by a power-law pivoting at an unusually low energy of～2 ke V,suggests intricate variations in the thermal Comptonization processes within the ***,when the data below 2 ke V are included,we identify that the soft excess component adds significant complexity to the spectral variability,such as evidenced by a transition from“harder-when-brighter”to“softer-when-brighter”during another single *** extra complexity arises because the variability of the soft excess sometimes follows and sometimes does not follow the changes in the power-law *** findings underscore the necessity of applying multiple analytic techniques to fully capture the multifaceted spectral variability of AGNs.

关键词： galaxies: active galaxies: Seyfert X-rays: galaxies

First observation results of Macao science Satellite-1 on lightning-induced electron precipitation

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science China Earth sciences 2025年第1期68卷 1-10页

作者： Yongping WANG Yixin SUN Qiugang ZONG Gaopeng LU Xudong GU Ze-Jun HU Bin LI Key Laboratory for Polar science Ministry of Natural ResourcesPolar Research Institute of ChinaShanghai 200136China Institute of space Physics and applied Technology Peking UniversityBeijing 100871China State Key Laboratory of Lunar and Planetary science Macao University of Science and TechnologyMacao 999078China School of Earth and space sciences University of Science and Technology of ChinaHefei 230026China School of Electronic Information Wuhan UniversityWuhan 430072China

The Medium-energy Electron Spectrometers(MES)is a space-borne instrument onboard Macao science Satellite-1(MSS-1)dedicated to monitoring the typical charged particle radiation characteristics in the satellite orbit and the process of their occurrence and development,including short bursts of lightning-induced electron precipitation(LEP).This paper presents the first results of the LEP measurements by the MSS-1.47 LEP events are identified with the routine operation for 3 months since satellite launch,all within the range of 1.5

关键词： Lightning-induced electron precipitation Inner radiation belts Energetic electrons Macao science Satellite-1

Separation of the ionospheric and thermospheric contributions in the data from the Triple Ionosophere Photo Meter onboard the Feng-Yun 3E satellite

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science China Earth sciences 2025年第1期68卷 172-184页

作者： Fang JIANG Tian MAO Jin-Song WANG Xiu-Qing HU Xiao-Xin ZHANG Liping FU Nan JIA Tianfang WANG National space science center Chinese Academy of SciencesBeijing100090China Beijing Key Laboratory of space Environment Exploration Beijing100090China Key Laboratory of Environmental space Situation Awareness Technology Beijing100090China National Satellite Meteorological center China Meteorological AdministrationBeijing100081China

The Triple Ionosphere Photo Meter(TRIPM)is a far ultraviolet nadir-view photometer that is onboard the secondgeneration,polar-orbiting Chinese meteorological satellite Feng-Yun 3E(FY-3E),which was launched on July 5,*** has three channels,and each is used to measure different types of emissions:(1)135.6 nm airglow produced by the recombination of the O+ions and electrons in the absence of sunlight(nighttime channel);(2)135.6 nm airglow from the OI when sunlight is present(daytime/dusk-dawn 135.6 nm channel);and(3)Airglow in the N_(2)LBH of the TRIPM(daytime/dusk-dawn N_(2)LBH channel).FY-3E is a satellite operating in the early morning ***,the data are mostly distributed on the dawndusk side or at times when the solar zenith angle is relatively *** this study,combined with simulation calculations,the data are *** further explore the application value of the data products,a model is used to separate the ionospheric radiative recombination contribution from the thermosphere photoelectron impact excitation contribution in the data from the daytime/dusk-dawn 135.6 nm *** approach not only improves the accuracy of O/N_(2)derived from the 135.6 nm channel and N_(2)LBH channel but also provides the ionospheric 135.6 nm radiance at the same time as the *** results show that the 135.6 nm radiance originating from the combination of O+and electrons extracted from the measurement data exhibits similar equatorial anomaly peak structure characteristics and seasonal variations as the corresponding GPS total electron content(TEC)*** the other hand,the separated 135.6 nm radiance generated from the thermosphere photoelectron collision excitation does not contain radiative recombination contributions;thus,the ionosphere influence is greatly avoided when the O/N_(2)is obtained.

关键词： Far ultraviolet 135.6 nm emission intensity Photoelectron impact excitation Radiative recombination excitation

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Anisotropic quark stars f（R,Lm,T） in gravity

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Chinese Physics C 2025年第02期 270-281页

作者： Takol Tangphati ?zzet Sakall Ayan Banerjee Anirudh Pradhan School of science Walailak University research center for Theoretical Simulation and applied research in Bioscience and Sensing Walailak University Physics Department Eastern Mediterranean University Atrophysics research Centre School of MathematicsStatistics and Computer ScienceUniversity of Kwa Zulu–Natal Centre for Cosmology Astrophysics and Space ScienceGLA University

We investigated the impact of f（R,Lm,T） gravity on the internal structure of compact stars,expecting this theory to manifest prominently in the high-density cores of such *** considered the algebraic function f（R,Lm,T）=R+αTLm,where a represents the matter-geometry coupling *** specifically chose the matter Lagrangian density Lm=-ρ to explore compact stars with anisotropic *** this end,we employed the MIT bag model as an equation of ***,we numerically solved the hydrostatic equilibrium equations to obtain mass-radius relations for quark stars（QSs）,examining static stability criteria,adiabatic index,and speed of ***,we used recent astrophysical data to constrain the coupling parameter a,which may lead to either larger or smaller masses for QSs,compared to their counterparts in general relativity.

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Synthesis of intermetallic PtCo fuel cell catalysts from bimetallic core@shell structured nanoparticles

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Journal of Energy Chemistry 2025年第2期101卷 1-6页

作者： Le Zhang Lei Tong Shuai Li Chang-Song Ma Kun-Ze Xue Hai-Wei Liang Hefei National research center for Physical sciences at the Microscale Department of Chemistry University of Science and Technology of China

The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells（PEMFCs）.However,forming intermetallic structures typically requires high-temperature annealing,posing a challenge for achieving well-size control and highly ordered *** we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo *** fabrication of the core@shell precursor involves using a molecular ligand containing both sulfur and oxygen donors to selectively bind with Pt colloidal nanoparticles as the core and chelate Co ions as the *** high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticles,preventing particle sintering;meanwhile,Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic *** benefits enable us to obtain the catalyst with finely dispersed nanoparticles（～3.5 nm）and a high ordering degree of 72%.With 0.1 mgPt/cm2cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm2at 0.67 V（H2-air）,and a voltage loss of 26 mV at 0.8 A/cm2after the accelerated durability test.

关键词： Bimetallic structure Fuel cells Intermetallic PtCo Oxygen reduction reaction