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Study of beam divergence and thrust vector eccentricity characteristics of the Hall thruster based on dual Faraday probe array planes and its applications

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Plasma science and technology 2023年第5期25卷 104-115页

作者：陈新伟赵勇田恺高俊孙明明孙新锋郭宁张宏王尚民冯杰陈焘耿海杨俊泰史楷 Science and Technology on Vacuum Technology and Physics Laboratory Lanzhou Institute of PhysicsLanzhou 730000People’s Republic of China

The accurate knowledge of the thrust vector eccentricity and beam divergence characteristics of Hall thrusters are of significant engineering value for the beneficial integration and successful application of Hall thrusters on *** the characteristics of the plume bipolar diffusion due to the annular discharge channel of the Hall thruster,a Gaussian-fitted method for thrust vector deviation angle and beam divergence of Hall thrusters based on dual Faraday probe array planes was proposed in respect of the Hall thruster beam *** results show that the ratios of the deviation between the maximum and minimum values of the beam divergence angle and the thrust vector eccentricity angle using a Gaussian fit to the optimized Faraday probe dual plane to the mean value are 1.4%and 11.5%,*** optimized thrust vector eccentricity angle obtained has been substantially improved,by approximately 20%.The beam divergence angle calculated using a Gaussian fitting to the optimized Faraday probe dual plane is approximately identical to the non-optimized *** beam divergence and thrust vector eccentricity angles for different anode mass flow rates were obtained by averaging the beam divergence and thrust vector eccentricity angles calculated by the dual-plane,Gaussian-fitted ion current density method for different *** study not only allows for an immediate and effective tool for determining the design of thrust vector adjustment mechanisms of spacecraft with different power Hall thrusters but also for characterizing the 3D spatial distribution of the Hall thruster plume.

关键词： Hall thruster beam divergence thrust vector eccentricity dual Faraday probe array planes

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

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science China(physics,Mechanics & Astronomy) 2025年第5期68卷 220-227页

作者： Jun Li Ruisheng Zheng Xiaoqian Wang Yao Chen School of Space Science and Technology Institute of Space SciencesShandong UniversityWeihai 264209China Center for Integrated Research on Space Science Astronomyand PhysicsInstitute of Frontier and Interdisciplinary ScienceShandong UniversityQingdao 266237China

Coronal extreme ultraviolet(EUV)waves are large-scale disturbances propagating in the corona and are closely associated with solar *** 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 211Achannels with temperatures ranging from 1.6 to 2 ***,we report a peculiar EUV wave that was invisible in the 193 and 211Abut appeared instead in AIA 171A,corresponding to a lower *** 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 *** addition,the fields extrapolated using the potential field source surface(PFSS)method indicate the existence of a typical pseudo-streamer ***,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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Improving the spaceborne GNSS-R altimetric precision based on the novel multilayer feedforward neural network weighted joint prediction model

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Defence technology（防务技术） 2024年第2期32卷 271-284页

作者： Yiwen Zhang Wei Zheng Zongqiang Liu Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100094China China Academy of Aerospace Science and Innovation Beijing 100176China State Key Laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information EngineeringBeijing 100194China

Global navigation satellite system-reflection(GNSS-R)sea surface altimetry based on satellite constellation platforms has become a new research direction and inevitable trend,which can meet the altimetric precision at the global scale required for underwater *** present,there are still research gaps for GNSS-R altimetry under this mode,and its altimetric capability cannot be specifically ***,GNSS-R satellite constellations that meet the global altimetry needs to be ***,the matching precision prediction model needs to be established to quantitatively predict the GNSS-R constellation altimetric ***,the GNSS-R constellations altimetric precision under different configuration parameters is calculated,and the mechanism of the influence of orbital altitude,orbital inclination,number of satellites and simulation period on the precision is analyzed,and a new multilayer feedforward neural network weighted joint prediction model is ***,the fit of the prediction model is verified and the performance capability of the model is tested by calculating the R2 value of the model as 0.9972 and the root mean square error(RMSE)as 0.0022,which indicates that the prediction capability of the model is ***,using the novel multilayer feedforward neural network weighted joint prediction model,and considering the research results and realistic costs,it is proposed that when the constellation is set to an orbital altitude of 500 km,orbital inclination of 75and the number of satellites is 6,the altimetry precision can reach 0.0732 m within one year simulation period,which can meet the requirements of underwater navigation precision,and thus can provide a reference basis for subsequent research on spaceborne GNSS-R sea surface altimetry.

关键词： GNSS-R satellite constellations Sea surface altimetric precision Underwater navigation Multilayer feedforward neural network

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Diverse glasses revealed from Chang'E-5 lunar regolith

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National science Review 2023年第12期10卷 150-163页

作者： Rui Zhao Laiquan Shen Dongdong Xiao Chao Chang Yao Huang Jihao Yu Huaping Zhang Ming Liu Shaofan Zhao Wei Yao Zhen Lu Baoan Sun Haiyang Bai Zhigang Zou Mengfei Yang Weihua Wang Institute of Physics Chinese Academy of Sciences Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Qian Xuesen Laboratory of Space Technology China Academy of Space Technology Songshan Lake Materials Laboratory College of Engineering and Applied Sciences Nanjing University China Academy of Space Technology

Lunar glasses with different origins act as snapshots of their formation processes,providing a rich archive of the Moon's formation and ***,we reveal diverse glasses from Chang'E-5(CE-5) lunar regolith,and clarify their physical origins of liquid quenching,vapor deposition and irradiation damage *** series of quenched glasses,including rotation-featured particles,vesicular agglutinates and adhered melts,record multiple-scale impact *** micro-impact products,like micron-to nano-scale glass droplets or craters,highlight that the regolith is heavily reworked by frequent micrometeorite *** from Apollo samples,the indigenous ultra-elongated glass fibers drawn from viscous melts and the widespread ultra-thin deposited amorphous rims without nanophase iron particles both indicate a relatively gentle impact environment at the CE-5 landing *** clarification of multitype CE-5 glasses also provides a catalogue of diverse lunar glasses,meaning that more of the Moon' s mysteries,recorded in glasses,could be deciphered in future.

关键词： lunar glasses glass fibers amorphous rims micrometeorite impacts gentle impact environment

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New constraints on exotic spin-dependent interactions with an ensemble-NV-diamond magnetometer

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National science Review 2023年第7期10卷 107-113页

作者： Hang Liang Man Jiao Yue Huang Pei Yu Xiangyu Ye Ya Wang Yijin Xie Yi-Fu Cai Xing Rong Jiangfeng Du CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China School of Astronomy and Space Science University of Science and Technology of China

laboratory search of exotic interactions is crucial for exploring physics beyond the standard *** report new experimental constraints on two exotic spin-dependent interactions at the micrometer scale based on ensembles of nitrogen-vacancy（NV） centers in diamond.A thin layer of NV ele ctronic spin ensembles is synthesized as the solid-state spin quantum sensor,and a lead sphere is taken as the interacting nucleon *** result establishes new bounds for two types of exotic spin interactions at the micrometer *** an exotic parity-odd spin-and velocity-dependent interaction,improved bounds are set within the force range from 5 to 500 μ*** upper limit of the corresponding coupling constant gAegVNat 330 μm is more than 1000-fold more stringent than the previous *** the P,T-violating scalar-pseudoscalar nucleon-electron interaction,improved constraints are established within the force range from 6 to 45 μ*** limit of the corresponding coupling constant gSNgPeis improved by more than one order of magnitude at 30μ*** work demonstrates that a solid-state NV ensemble can be a powerful platform for probing exotic spin-dependent interactions.

关键词： quantum sensing exotic interaction diamond nitrogen-vacancy center beyond the standard model

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An internal ballistic model of electromagnetic railgun based on PFN coupled with multi-physical field and experimental validation

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Defence technology（防务技术） 2024年第2期32卷 254-261页

作者： Benfeng Gu Haiyuan Li Baoming Li National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China

To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore *** this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried *** test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of *** the simulation results and experimental data,the damage condition of the contact surface is analyzed.

关键词： Internal ballistic modeling Electromagnetic rail gun Multi-physics field coupling Experimental validation PFN

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Multiplexed wavefront sensing using a grating array-based wavefront sensor

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Optics Express 2025年第3期33卷 4437-4445页

作者： Singh, Jaspal Pathak, Biswajit Narayanamurthy, C.S. Ganesan, A.R. Applied Optics Laboratory Department of Physics Indian Institute of Technology Madras Tamil Nadu Chennai600036 India Applied and Adaptive Optics Laboratory Department of Physics Indian Institute of Space Science and Technology Kerala Thiruvananthapuram695547 India

This paper addresses the ambiguity problem associated with a periodic array of spots in the Shack-Hartmann wavefront sensor (SHWS) when used for multiplexed wavefront sensing, corresponding to multiple isoplanatic patches. We overcome this issue by introducing a multiplexed wavefront sensing scheme, utilizing a grating array-based wavefront sensor that is a programmable version of SHWS. Three beams representing lights from three distinct guide stars are generated to validate the proposed scheme. Each beam passed through different regions of a pseudo-random phase plate, resulting in different random phases that mimic turbulence effects. We detected three wavefronts from a single frame of data by employing a binary phase grating array on a spatial light modulator at the pupil plane. The proposed sensing scheme is compatible with existing wavefront reconstruction algorithms. This study has potential applications in multi-conjugate adaptive optics, where multiple wavefront sensors are needed to detect various isoplanatic patches in order to expand the field of view in turbulent conditions. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Adaptive optics

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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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Analysis of scattering characteristics of coating materials through coupling of BRDF spectral polarization imaging with Torrance-Sparrow model

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Optoelectronics Letters 2025年第5期21卷 271-277页

作者： CHEN Feng CHEN Guibo ZHANG Ye WANG Jianbo LIU Yanli XUE Fang School of Physics Changchun University of Science and Technology Beijing Institute of Space Mechanics & Electricity

To identify coatings and analyze the anti-detection capabilities of camouflage patterns, material samples can be prepared using the super-pixel segmentation method. A spectral polarization imaging system is developed, based on the principle of bidirectional reflectance distribution function(BRDF), to obtain spectral reflection intensities of coatings at full spatial angles, and use polarization images to calculate the refractive index by the Fresnel equation. The index is then coupled into TorranceSparrow model to simulate the spectral scattering intensity to mutually verify the experimental results. The spectral scattering characteristics of standard camouflage patterns are then revealed and pinpoint the signature band and the angle of reflecting sensitivity.

关键词： A

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