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Observations of a peculiar coronal wave inside a pseudo-streamer structure

science China(Physics,Mechanics & Astronomy) 2025年第5期Mechanics & Astronomy) .卷 224-231页

作者： Jun Li Ruisheng Zheng Xiaoqian Wang Yao Chen School of Space Science and Technology Institute of Space Sciences Shandong University Center for Integrated Research on Space Science Astronomy and Physics Institute of Frontier and Interdisciplinary ScienceShandong University

Coronal extreme ultraviolet（EUV） waves are large-scale disturbances propagating in the corona and are closely associated with solar eruptions. They can disturb the ambient plasma over a wide temperature range, resulting in simultaneous observations in multiple EUV passbands, and the wavefronts are typically best observed in AIA 193 and 211 ? channels with temperatures ranging from 1.6 to 2 MK. Here, we report a peculiar EUV wave that was invisible in the 193 and 211 ? but appeared instead in AIA 171 ?, corresponding to a lower temperature. Driven by a coronal jet, the wave propagated at a speed of ～560 kms-1. The differential emission measure（DEM） analysis shows that the emission of the wavefront concentrated at ～1.25 MK, lower than the typical predominant temperatures. In addition, the fields extrapolated using the potential field source surface（PFSS） method indicate the existence of a typical pseudo-streamer structure. Hence, we propose that it is possibly the first case of an EUV wave occurring and propagating inside a pseudo-streamer, and its visibility is likely determined by the relatively cooler plasma within the pseudo-streamer.

关键词： MHD waves prominence eruptions coronal streamers

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space-based optical lattice clocks as gravitational wave detectors in search for new physics

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science China(Physics,Mechanics & Astronomy) 2025年第4期68卷 244-252页

作者： Bo Wang Bichu Li Qianqian Xiao Geyu Mo Yi-Fu Cai Department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei230026China CAS Key Laboratory for Research in Galaxies and Cosmology School of Astronomy and Space ScienceUniversity of Science and Technology of ChinaHefei230026China Deep Space Exploration Laboratory Hefei230088China

We investigate the sensitivity and performance of space-based optical lattice clocks(OLCs)in detecting gravitational waves,in particular the stochastic gravitational wave background(SGWB)at low frequencies(10^(-4),1)Hz,which are inaccessible to ground-based *** first analyze the response characteristics of a single OLC detector for SGWB detection and compare its sensitivity with that of laser interferometer space antenna(LISA).Due to longer arm lengths,space-based OLC detectors can exhibit unique frequency responses and enhance the capability to detect SGWB in the low-frequency range,but the sensitivity of a single OLC detector remains insufficient overall compared with ***,as a preliminary plan,we adopt a method of crosscorrelation on two OLC detectors to improve the signal-to-noise ratio(SNR).This method leverages the uncorrelated origins but statistically similar properties of noise in two detectors while the SGWB signal is correlated between them,thus achieving effective noise suppression and sensitivity *** advancements in OLC stability are expected to further enhance their detection *** work highlights the potential of OLC detectors as a promising platform for SGWB detection,offering complementary capabilities to LISA,and opening an observational window into more astrophysical sources and the early universe.

关键词： gravitational wave detectors optical lattice clocks stochastic gravitational background

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Latitudinal distribution and propagation of lightning-generated whistler:A statistical study by Van Allen Probes observation and ray-tracing simulation

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science China Earth sciences 2025年第4期68卷 1291-1297页

作者： Zhaoguo HE Jiang YU Xiangling DING Zuzheng CHEN Nigang LIU Yuguang YE Jun CUI Qiugang ZONG State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao999078China CNSA Macao Center for Space Exploration and Science Macao999078China Zhuhai MUST Science and Technology Research Institute Macao University of Science and TechnologyZhuhai519000China Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai519000China Institute of Space Physics and Applied Technology Peking UniversityBeijing100871China

Lightning-generated whistler(LGW)is an important electromagnetic wave in the magnetosphere,causing energetic electron *** we analyze the LGW distribution and propagation using Van Allen Probes data and ray-tracing *** statistics show that LGW occurs more frequently at L<2.5 with higher amplitudes in the northern *** Poynting flux demonstrates that LGW originates from both hemispheres within L~2.5,and propagates into the space as the wave power *** wave normal angle distributions indicate that LGW propagates quasi-parallel to the field line near its source and becomes oblique as the magnetic latitude ***,we use the ray-tracing model to simulate the LGW propagation,and statistically analyze the propagation characteristics of LGW,which are consistent with the observational *** paper presents the latitudinal distribution and propagation properties of LGW based on statistics for the first time,providing new insights into the LGW generation and evolution in the magnetosphere.

关键词： Lightning-generated whistler Ray-tracing model Magnetosphere Wave distribution Wave propagation

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Estimating the Dst index using machine learning from IMAGE/HENA observations

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Advances in space research 2025年第6期75卷 4786-4794页

作者： Yan, Yuheng Yu, Xiancai Zhang, Xianguo Sun, Tianran Beijing Key Laboratory of Space Environment Exploration National Space Science Center Chinese Academy of Sciences Beijing China School of Computer Science and Technology University of Chinese Academy of Sciences Beijing China State Key Laboratory of Space Weather National Space Science Center CAS Beijing China

This study presents a novel approach to estimating the Disturbance Storm Time (Dst) index, a critical measure of geomagnetic storm activity, using Energetic Neutral Atom (ENA) observations from the High Energy Neutral Atom (HENA) imager on the IMAGE satellite. By applying machine learning techniques—specifically multilayer perceptrons (MLPs) and convolutional neural networks (CNNs) to ENA data from 2000 to 2005, we developed models that achieve a root mean square error (RMSE) of 18.96 nT and a correlation coefficient (R) of 0.87 in predicting the Dst index. This method offers a new, global perspective on geomagnetic storm dynamics by leveraging satellite-based ENA data, enhancing spatial and temporal resolution beyond ground-based magnetometer measurements. These findings show the potential of machine learning in improving space weather forecasting and deepening our understanding of geomagnetic storm dynamics. © 2024

关键词： Convolutional neural networks

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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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Particle motion and enrichment behavior of dense granular impinging-jets generated by the nozzle with rectangular orifice

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Particuology 2025年第1期96卷 312-327页

作者： Ting Li Qingguo Lin Haokun Liu Shengju Wang Weifeng Li National Energy Coal Gasification Technology Research and Development Center Shanghai Engineering Research Center of Coal GasificationEngineering Research Center of Resource Utilization of Carbon-containing Waste with Carbon NeutralityMinistry of EducationEast China University of Science and TechnologyShanghai200237China Shanghai Engineering Research Center of Space Engine Shanghai Institute of Space PropulsionShanghai201112China

Particle motion regime and enrichment behavior of dense granular impinging-jets formed by the nozzle with rectangular orifice are experimentally and numerically *** impingement patterns are identified,including long and short parallel *** enrich in the central axis of the granular sheet when two jets impinge with the long axes parallel *** at the short axes parallel pattern,particles generate two symmetrical enriched *** angle of particle-enriched streams is observed to increase with increasing angle of two impinging-jets and decreasing aspect ratio of the nozzle *** particle image velocity(PIV)analysis results demonstrate that the circumferential distribution of the particle velocity on the granular sheet follows the Gaussian *** the formation of particle-enriched streams,the concentration distribution of the particle evolves into a trimodal *** of the discrete element method(DEM)indicate that the core region with low velocity within the impact zone of impinging-jets generated by using two nozzles with rectangular orifices extends into a shuttle *** core region develops and extends along the horizontal(or vertical)directions at long(or short)axes impingement pattern,thereby,affecting the enrichment behavior of particles.

关键词： Dense granular impinging-jet Enrichment behavior Rectangular orifice

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An embedded electron current layer observed at the edge of the plasma sheet in the Earth’s magnetotail

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Earth and Planetary Physics 2025年第1期9卷 148-158页

作者： ChenChen Zhan RongSheng Wang QuanMing Lu San Lu XinMin Li Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences(CAS)Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Anhui Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Collaborative Innovation Center of Astronautical Science and Technology Harbin 150001China

The formation of an embedded electron current sheet within the magnetotail plasma sheet has been poorly *** this article,we present an electron current layer detected at the edge of the magnetotail plasma *** ions were demagnetized inside the electron current layer,but the electrons were still frozen in with the magnetic field ***,this decoupling of ions and electrons gave rise to a strong Hall electric field,which could be the reason for the formation of the embedded thin current *** magnetized electrons,the absence of the nongyrotropic electron distribution,and negligible energy dissipation in the layer indicate that magnetic reconnection had not been triggered within the embedded thin current *** highly asymmetric plasma on the two sides of the current layer and low magnetic shear across it could suppress magnetic *** observations indicate that the embedded electric current layer,probably generated by the Hall electric field,even down to electron scale,is not a sufficient condition for magnetic reconnection.

关键词： magnetotail plasma sheet magnetic reconnection

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Calibration of the Solar X-ray Detector on-board the Macao science Satellite-1B for Soft X-ray Detection

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science China Earth sciences 2025年第1期68卷 11-26页

作者： Man-Hei NG Xiaoping ZHANG Jianwu CHEN Yongqiang SHI Fuchang ZUO Wenxi PENG Weichun FU Liansheng LI Pengwei LUO Chi-Long TANG Guozheng ZHANG Zhiwu MEI Li WANG Cunhui LI Jiaming OU Yanyan Xu State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao999078China Space Optoelectronic Measurement and Perception Laboratory Beijing Institute of Control EngineeringBeijing100190China Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of PhysicsLanzhou730000China China National Space Administration(CNSA) Macao Center for Space Exploration and ScienceMacao999078China

The Solar X-ray Detector(SXD)on-board the Macao science Satellite-1B(MSS-1B)was successfully launched via the Chinese Long March-2C rocket on 21 May 2023,and commenced operations in early June of the same *** MSS-1B/Soft X-ray Detection Units(SXDUs)employ two silicon drift detectors(SDDs),providing a wide range of energy spectra spanning from 0.7 to 24 ***,the SXDUs deliver a high-resolution capability of 0.14 keV@5.9 keV and operate with a time cadence of 1 ***,we perform thorough calibrations of the MSS-1B/SXDUs,employing a combination of ground experiments and *** addition,quantitative analysis comparing the flux measurements obtained by the MSS-1B/SXDUs to the data collected by the Geostationary Operational Environmental Satellite(GOES),provides compelling evidence of their ***,the preliminary spectral analysis results showcase the robustness and expected performance of the MSS-1B/SXDUs,unlocking their potential for facilitating the study of dynamic evolution of solar ***,the innovative MSS-1B/Solar X-ray Detector facilitates concurrent observations of solar soft and hard X-rays,thereby making valuable contributions to the advancements in solar research.

关键词： Macao science Satellite-1B(MSS-1B) Calibration Solar X-Ray Detector Spectrometer Soft X-rays Solar flares Solar abundances

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A deeper and hotter Martian core-mantle differentiation inferred from FeO partitioning

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science Bulletin 2025年第3期70卷 429-436页

作者： Yunguo Li Chunhui Li You Zhou Yun Liu Huaiwei Ni State Key Laboratory of Lithospheric and Environmental Coevolution University of Science and Technology of ChinaHefei 230026China Deep Space Exploration Laboratory/School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Research Centre for Planetary Science College of Earth and Planetary SciencesChengdu University of TechnologyChengdu 610059China State Key Laboratory of Ore Deposit Geochemistry Chinese Academy of SciencesGuiyang 550081China

The core-mantle differentiation process plays a pivotal role in redistributing material on a massive scale,shaping the long-term evolution of rocky *** this process is crucial for gaining insights into the accretion and evolution of planets like ***,the details of Mars’s core-mantle differentiation remain poorly understood due to limited compositional data for its core and *** this study,we aim to constrain the Martian core-mantle differentiation by examining FeO partitioning between core and mantle materials,incorporating improved Martian compositional data from the InSight *** ab initio thermodynamic techniques,we calculated the FeO partition coefficient between liquid iron and silicate *** results align with previous studies while also clarifying the factors affecting partitioning *** on these findings and estimates of oxygen concentration in the core,we infer that Mars’s core and mantle likely differentiated at temperatures above 2440 K and pressures ranging from 14 to 22 *** these estimates are higher than previously reported,they are consistent with observed abundances of moderately siderophile elements and Mars’s accretion models.

关键词： Mars Core-mantle differentiation Volatile Partitioning

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Layout optimization and performance analysis of large array of imaging atmospheric Cherenkov telescopes

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Chinese Physics C 2025年第3期49卷 161-170页

作者： Zhipeng Zhang Ruizhi Yang Shoushan Zhang Zhen Xie Jiali Liu Liqiao Yin Yudong Wang Lingling Ma Zhen Cao School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory for Research in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaHefei 230026China Deep Space Exploration Laboratory/School of Physical Sciences University of Science and Technology of ChinaHefei 230026China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsBeijing 100049China Department of Physics University of Chinese Academy of SciencesBeijing 100049China Tianfu Cosmic Ray Research Center Chengdu 610299China

The large array of imaging atmospheric Cherenkov telescopes(LACT)is a planned array of 32 Cherenkov telescopes,each featuring 6-m diameter mirrors,to be constructed at the LHAASO *** study focused on optimizing the array layout and analyzing the performance of *** observation modes were examined:large zenith angle observations for ultra-high energy events and small zenith angle observations for lower energy *** large zenith angles(60°),simulations indicate that an 8-telescope subarray can achieve an effective area of 3km^(2)with excellent angular *** small zenith angles,we optimized the layout of 4-telescope cells and the full 32-telescope *** energy threshold of the full array is approximately 200 GeV,which is particularly crucial for studying transient phenomena such as gamma-ray bursts(GRBs)and active galactic nuclei(AGNs).This study provides essential guidance for finalizing the LACT layout design and estimating performance under various observational *** also highlights the potential of LACT for conducting deep observations of ultra-high energyγ-ray sources,performing morphological studies of PeVatrons,and advancing time-domainγ-ray astronomy.

关键词： IACT γ-ray LHAASO

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