Leading national space exploration agencies and private enterprises are actively engaged in lunar exploration initiatives to accomplish manned lunar landings and establish permanent lunar bases in the forthcoming year...Leading national space exploration agencies and private enterprises are actively engaged in lunar exploration initiatives to accomplish manned lunar landings and establish permanent lunar bases in the forthcoming years.With limited access to lunar surface materials on Earth,lunar regolith simulants are crucial for lunar exploration research.The Chang’e-5(CE-5)samples have been characterized by state-of-the-art laboratory equipment,providing a unique opportunity to develop a high-quality lunar regolith simulant.We have prepared a high-fidelity PolyU-1 simulant by pulverizing,desiccating,sieving,and blending natural mineral materials on Earth based on key physical,mineral,and chemical characteristics of CE-5 samples.The results showed that the simulant has a high degree of consistency with the CE-5 samples in terms of the particle morphology,mineral and chemical composition.Direct shear tests were conducted on the simulant,and the measured internal friction angle and cohesion values can serve as references for determining the mechanical properties of CE-5 lunar regolith.The PolyU-1 simulant can contribute to experimental studies involving lunar regolith,including the assessment of interaction between rovers and lunar regolith,as well as the development of in-situ resource utilization(ISRU)technologies.展开更多
After landing in the Utopia Planitia,Tianwen-1 formed the deepest landing crater on Mars,approximately 40 cm deep,exposing precious information about the mechanical properties of Martian soil.We established numerical ...After landing in the Utopia Planitia,Tianwen-1 formed the deepest landing crater on Mars,approximately 40 cm deep,exposing precious information about the mechanical properties of Martian soil.We established numerical models for the plume-surface interaction(PSI)and the crater formation based on Computational Fluid Dynamics(CFD)methods and the erosion model modified from Roberts’Theory.Comparative studies of cases were conducted with different nozzle heights and soil mechanical properties.The increase in cohesion and internal friction angle leads to a decrease in erosion rate and maximum crater depth,with the cohesion having a greater impact.The influence of the nozzle height is not clear,as it interacts with the position of the Shock Diamond to jointly control the erosion process.Furthermore,we categorized the evolution of landing craters into the dispersive and the concentrated erosion modes based on the morphological characteristics.Finally,we estimated the upper limits of the Martian soil’s mechanical properties near Tianwen-1 landing site,with the cohesion ranging from 2612 to 2042 Pa and internal friction angle from 25°to 41°.展开更多
In this work,we aim to investigate the origin of the magnetic carriers in the lunar crust and the intensity of the ancient dynamo field.The magnetization and depth range of magnetic carriers are studied under a weak a...In this work,we aim to investigate the origin of the magnetic carriers in the lunar crust and the intensity of the ancient dynamo field.The magnetization and depth range of magnetic carriers are studied under a weak and a strong magnetic anomaly in Mare Tranquillitatis and in Oceanus Procellarum,respectively,where the surface ages are 3.6 and 3.3 billion years.A sophisticated three-dimensional amplitude inversion software program from a geophysical survey is used to reconstruct the distributions of magnetization in the lunar crust.Because no globally measured surface magnetic field exists for the Moon,a crustal magnetic anomaly model with a grid resolution of 0.2°is used.The depth range of the magnetic source is fixed by the boundary identified by a relative criterion,which is 20%of the recovered maximum magnetization.The central burial depths of the magnetic carriers are approximately 15 km and 25 km under Reiner Gamma and Mare Tranquillitatis,respectively.The volumes of the two magnetic sources are at scales of 104 and 105 km3,respectively.The aforementioned differences may imply a hotter crust under Reiner Gamma than Mare Tranquillitatis by 3.3 billion years.The results support the view that the magma intrusions magnetized by an ancient magnetic field could be the origin of magnetic anomalies under Reiner Gamma and Mare Tranquillitatis.Compared with previous works,the maximum magnetization of 3 A/m under Reiner Gamma supports the intensity of the field being several microteslas.展开更多
Magnetic reconnection and dipolarization are crucial processes driving magnetospheric dynamics,including particle energization,mass circulation,and auroral processes,among others.Recent studies have revealed that thes...Magnetic reconnection and dipolarization are crucial processes driving magnetospheric dynamics,including particle energization,mass circulation,and auroral processes,among others.Recent studies have revealed that these processes at Saturn and Jupiter are fundamentally different from the ones at Earth.The reconnection and dipolarization processes are far more important than previously expected in the dayside magnetodisc of Saturn and potentially Jupiter.Dayside magnetodisc reconnection was directly identified by using Cassini measurements(Guo RL et al.,2018b)and was found to be drizzle-like and rotating in the magnetosphere of Saturn(Delamere et al.,2015b;Yao ZH et al.,2017a;Guo RL et al.,2019).Moreover,magnetic dipolarization could also exist at Saturn’s dayside(Yao ZH et al.,2018),which is fundamentally different from the terrestrial situation.These new results significantly improve our understanding of giant planetary magnetospheric dynamics and provide key insights revealing the physics of planetary aurorae.Here,we briefly review these recent advances and their potential implications for future investigations.展开更多
The present issue of Earth and Planetary Physics is dedicated to the near-space neutral and plasma environments of Mars.The issue includes nine papers that present new results on the properties of the Martian exospher...The present issue of Earth and Planetary Physics is dedicated to the near-space neutral and plasma environments of Mars.The issue includes nine papers that present new results on the properties of the Martian exosphere,ionosphere,and magnetosphere,from both observational and modeling points of view.Due to the similarity between the two objects,the issue also includes two additional papers on the near-Venus plasma environment.展开更多
During the current interglacial period,conditions on Earth,the homeland of humankind,fostered the emergence of large-scale human cooperation,the unique phenomenon that we call civilization.Since then,humans everywhere...During the current interglacial period,conditions on Earth,the homeland of humankind,fostered the emergence of large-scale human cooperation,the unique phenomenon that we call civilization.Since then,humans everywhere on Earth,standing under the vast starlit sky,have thought about and explored our展开更多
The plume-surface interaction(PSI)is a common phenomenon that describes the environment surrounding the landers resulting from the impingement of hot rocket exhaust on the regolith of planetary bodies.The PSI will cau...The plume-surface interaction(PSI)is a common phenomenon that describes the environment surrounding the landers resulting from the impingement of hot rocket exhaust on the regolith of planetary bodies.The PSI will cause obscuration,erosion of the planetary surface,and high-speed spreading of dust or high-energy ejecta streams,which will induce risks to a safe landing and cause damage to payloads on the landers or to nearby assets.Safe landings and the subsequent scientific goals of deep-space exploration in China call for a comprehensive understanding of the PSI process,including the plume flow mechanics,erosion mechanism,and ejecta dynamics.In addition,the landing crater caused by the plume provides a unique and insightful perspective on the understanding of PSI.In particular,the PSI can be used directly to constrain the composition,structure,and mechanical properties of the surface and subsurface soil.In this study,we conducted a systematic review of the phenomenology and terrestrial tests of PSI:we analyzed the critical factors in the PSI process and compared the differences in PSI phenomena between lunar and Martian conditions;we also reviewed the main erosion mechanisms and the evolution and development of terrestrial tests on PSI.We discuss the problems with PSI,challenges of terrestrial tests,and prospects of PSI,and we show the preliminary results obtained from the landing crater caused by the PSI of Tianwen-1.From analysis of the camera images and digital elevation model reconstructions,we concluded that the landing of Tianwen-1 caused the deepest crater(depth>40 cm)on a planetary surface reported to date and revealed stratigraphic layers in the subsurface of Martian soil.We further constrained the lower bounds of the mechanical properties of Martian soil by a slope stability analysis of the Tianwen-1 landing crater.The PSI may offer promising opportunities to obtain greater insights into planetary science,including the subsurface structure,mineral composition,and properties of soil.展开更多
This study reports the morphological characteristics of anomalous variations in Global Navigation Satellite System Total Electron Content(GNSS-TEC) prior to the strong local earthquakes(EQ) that occurred during the pe...This study reports the morphological characteristics of anomalous variations in Global Navigation Satellite System Total Electron Content(GNSS-TEC) prior to the strong local earthquakes(EQ) that occurred during the period of 2011-2015.We have analyzed 20 earthquakes of magnitude M> 5.6.A statistical technique is implemented on the data of six GNSS stations located in Tashkent,Kitab,and Maidanak in Uzbekistan,and Islamabad,Multan,Quetta in Pakistan.The results show continuous anomalous variations in TEC during 24 h befo re the occupancy of local earthquakes.It is shown that the precursors before the occurrence of strong earthquakes,in particular of magnitude 5.7,7.7,7.5,7.8 and 7.3 are detected near Eastern Uzbekistan(26 May 2013),Southwestern Pakistan(24 September 2013),Hindukush region of Afghanistan(26 October 2015),and Central Nepal(25 April 2015) and(12 May 2015),respectively.The ionospheric anomalies appearing before the strong earthquakes at six GNSS stations are registered in 14cases(70%) out of 20 selected EQs.It is depicted that anomalies referred to as ionospheric precursors appeared about 1-7 days prior to the occurrence of strong earthquakes.展开更多
By using a broadband Lg attenuation model developed for the Tibetan Plateau,we isolate source terms by removing attenuation and site effects from the observed Lg-wave displacement spectra of the M 7.0 earthquake that ...By using a broadband Lg attenuation model developed for the Tibetan Plateau,we isolate source terms by removing attenuation and site effects from the observed Lg-wave displacement spectra of the M 7.0 earthquake that occurred on August 8,2017,in Jiuzhaigou,China,and its aftershock sequence.Thus,the source parameters,including the scalar seismic moment,comer frequency and stress drop,of these events can be further estimated.The estimated stress drops vary from 47.1 kPa to 7149.6 kPa,with a median value of 59.4 kPa and most values falling between 50 kPa and 75 kPa.The estimated stress drops show significant spatial variations.Lower stress drops were mainly found close to the mainshock and on the seismogenic fault plane with large coseismic slip.In contrast,the highest stress drop was 7.1 MPa for the mainshock,and relatively large stress drops were also found for aftershocks away from the major seismogenic fault and at depths deeper than the zone with large coseismic slip.By using a statistical method,we found self-similarity among some of the aftershocks with a nearly constant stress drop.In contrast,the stress drop increased with the seismic moment for other aftershocks.The amount of stress released during earthquakes is a fundamental characteristic of the earthquake rupture process.As such,the stress drop represents a key parameter for improving our understanding of earthquake source physics.展开更多
We have constrained a small-scale,dome-shaped low-velocity structure near the core-mantle boundary(CMB)of Earth beneath Perm(the Perm anomaly)using travel-time analysis and three-dimensional(3-D)forward waveform model...We have constrained a small-scale,dome-shaped low-velocity structure near the core-mantle boundary(CMB)of Earth beneath Perm(the Perm anomaly)using travel-time analysis and three-dimensional(3-D)forward waveform modeling of seismic data sampling of the mantle.The best-fitting dome-shaped model centers at 60.0°E,50.5°N,and has a height of 400 km and a radius that increases from 200 km at the top to 450 km at the CMB.Its velocity reduction varies from 0%at the top to–3.0%at 240km above the CMB to–3.5%at the CMB.A surrounding 240-km-thick high-velocity D''structure has also been detected.The Perm anomaly may represent a stable smallscale chemical pile in the lowermost mantle,although the hypothesis of a developing mantle plume cannot be ruled out.展开更多
Magnetic reconnection processes and their impact on planetary magnetospheric dynamics exhibit significant differences due to differences in upstream solar wind conditions and internal planetary environments.Current un...Magnetic reconnection processes and their impact on planetary magnetospheric dynamics exhibit significant differences due to differences in upstream solar wind conditions and internal planetary environments.Current understanding of reconnection phenomena at Mercury is rooted in the MESSENGER mission.However,direct detection of reconnection remains rare.Here,we aim to assess the limitations of MESSENGER in detecting reconnection in Mercury’s space and to discuss key issues of reconnection that will be addressed by BepiColombo,including the dynamics of magnetic flux ropes,particle acceleration,density asymmetric reconnection,IMF-driven near-tail structures,and potential modes of magnetospheric convection.展开更多
Earth’s near space,located in the region between 20 and 100 km above sea level,is characterized by extreme conditions,such as low temperature,low atmospheric pressure,harsh radiation,and extreme dryness.These conditi...Earth’s near space,located in the region between 20 and 100 km above sea level,is characterized by extreme conditions,such as low temperature,low atmospheric pressure,harsh radiation,and extreme dryness.These conditions are analogous to those found on the surface of Mars and in the atmosphere of Venus,making Earth’s near space a unique natural laboratory for astrobiological research.To address essential astrobiological questions,teams from the Chinese Academy of Sciences(CAS)have developed a scientific balloon platform,the CAS Balloon-Borne Astrobiology Platform(CAS-BAP),to study the effects of near space environmental conditions on the biology and survival strategies of representative organisms in this terrestrial analog.Here,we describe the versatile Biological Samples Exposure Payload(BIOSEP)loaded on the CAS-BAP with respect to its structure and function.The primary function of BIOSEP is to expose appropriate biological specimens to the harsh conditions of near space and subsequently return the exposed samples to laboratories for further analysis.Four successful flight missions in near space from 2019 to 2021 have demonstrated the high reliability and efficiency of the payload in communicating between hardware and software units,recording environmental data,exposing sample containers,protecting samples from external contamination,and recovering samples.Understanding the effects of Earth’s near space conditions on biological specimens will provide valuable insights into the survival strategies of organisms in extreme environments and the search for life beyond Earth.The development of BIOSEP and associated biological exposure experiments will enhance our understanding of the potential for life on Mars and the habitability of the atmospheric regions of other planets in the solar system and beyond.展开更多
Using over eight years of Mars Atmosphere and Volatile Evolutio N(MAVEN)data,from November 2014 to May 2023,we have investigated the Martian nightside ionospheric magnetic field distribution under the influence of ups...Using over eight years of Mars Atmosphere and Volatile Evolutio N(MAVEN)data,from November 2014 to May 2023,we have investigated the Martian nightside ionospheric magnetic field distribution under the influence of upstream solar wind drivers,including the interplanetary magnetic field intensity(∣BIMF∣),solar wind dynamic pressure(PS W),solar extreme ultraviolet flux(EUV),and Martian seasons(L s).Our analysis reveals pronounced correlations between magnetic field residuals and both∣BIMF∣and PS W.Correlations observed with EUV flux and Ls were weaker—notably,magnetic field residuals increased during periods of high EUV flux and at Mars perihelion.We find that the IMF penetrates to an altitude of 200 km under a wide range of upstream conditions,penetrating notably deeper under high∣BIMF∣andPSWconditions.Our analysis also indicates that EUV flux and IMF cone angle have minimal impact on IMF penetration depth.Those findings provide useful constraints on the dynamic nature of Martian atmospheric escape processes and their evolution,suggesting that historical solar wind conditions may have facilitated deeper IMF penetration and higher rates of ionospheric escape than are observed now.Moreover,by establishing criteria for magnetic‘quiet’conditions,this study offers new insights into the planet’s magnetic environment under varying solar wind influences,knowledge that should help refine models of the Martian crustal magnetic field.展开更多
Jupiter is one of the top priorities for deep space exploration in China and other countries.The structure of Jupiter’s interior,in particular,is a crucial but still unclear scientific topic.This paper discusses curr...Jupiter is one of the top priorities for deep space exploration in China and other countries.The structure of Jupiter’s interior,in particular,is a crucial but still unclear scientific topic.This paper discusses current scientific understanding of Jupiter’s interior by summarizing the history of past and current exploration and data analysis.We review recent space-based and ground-based observation methods and analyze their feasibility.To gain new insight into the internal structure of Jupiter,we propose to study Jupiter’s innards by planetary seismology.Ground-based observation,namely the Jupiter Seismologic Interferometer Polarization Imager(SIPI)in Lenghu,will be developed to obtain the Doppler velocity distribution on the surface of Jupiter and identify oscillation signals.Lenghu has observation conditions that are not only exceptional in China but even in the world,capable of providing novel insight into the interior of Jupiter.This will also be the first study in China of the interior of Jupiter using asteroseismology,which has significant implications for China’s plans to explore Jupiter via spacecraft-mounted instruments.展开更多
Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemis...Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemispheres is an important but challenging task.In this study,we used a combination of multiple observations and a model simulation to examine the north–south hemispheric difference in the I-T coupling system in the American and Asian sectors during the geomagnetic superstorm that occurred in May 2024.Observations of the total electron content(TEC)showed that the Asian sector had negative storms in the northern hemisphere and positive storms in the southern hemisphere,a process that exacerbated the hemispheric differences in the TEC.However,both hemispheres of the American sector showed negative storms.The thermospheric composition changes also differed between the two sectors,and their variation could partially explain the hemispheric differences caused by positive and negative storms.Moreover,the influence of the thermospheric density change was less than that of the thermospheric composition.Finally,the dynamic effect of the thermospheric wind and the plasma transport processes strongly modulated the north–south differences in the TEC at nighttime in the American and Asian sectors,respectively,during this superstorm.展开更多
The South China Block(SCB)was formed through the Neoproterozoic amalgamation of the Yangtze Block(YB),the Cathaysia Block(CB),and the accreted components of the Jiangnan orogenic belt(JNO),it is bounded by the Jiangs...The South China Block(SCB)was formed through the Neoproterozoic amalgamation of the Yangtze Block(YB),the Cathaysia Block(CB),and the accreted components of the Jiangnan orogenic belt(JNO),it is bounded by the Jiangshan–Shaoxing–Pingxiang fault(JSPF)and the Jiujiang–Shitai–Jishou fault(JSJF)(Yao et al.,2019).The SCB has undergone a series of complex geological events,including Paleozoic orogeny,Mesozoic collisions with the North China Craton(NCC)and the Indochina Block,as well as the intracontinental orogeny,leading to extensive lithospheric modifications and magmatic activities(Zhang H J et al.,2023;Fig.1).展开更多
Magnetosonic waves are an important medium for energy transfer in collisionless space plasma.Magnetosonic waves have been widely investigated in the upstream of the bow shock at Mars.These waves are believed to origin...Magnetosonic waves are an important medium for energy transfer in collisionless space plasma.Magnetosonic waves have been widely investigated in the upstream of the bow shock at Mars.These waves are believed to originate from pickup ions or reflected particles.By utilizing MAVEN spacecraft data,we have observed the occurrence of quasi-perpendicularly propagating magnetosonic emissions near the proton gyrofrequency in the Martian magnetotail region.These plasma waves are associated with a significant enhancement of proton and oxygen flux.The excited magnetosonic waves could possibly heat the protons through resonance and facilitate the ionospheric plasma escape.Our results could be helpful to better understand the Mars’magnetospheric dynamics and offer insights into possible energy redistribution between waves and plasma in the Martian nightside magnetosphere.展开更多
For city planning and reducing potential earthquake risk,it’s necessary to detect the information of the buried faults in an urban area especially,including the location and activities.An integrated technique with ge...For city planning and reducing potential earthquake risk,it’s necessary to detect the information of the buried faults in an urban area especially,including the location and activities.An integrated technique with geophysical and geological methods,including the shallow seismic reflection profile,electrical resistivity measurement,geologic borehole section,and exploration trench,was used to detect the Chengnanhe fault,which is one of the two main faults passing through the Weihai urban area in Shandong province,China.The results show that it is a normal fault striking with E-W direction,and it is relatively inactive and stable.By using the thermoluminescence(TL)dating,we found that the Chengnanhe fault initiated in mid-Pleistocene and there was no offset after late Pleistocene.Such an integrated technique with multiple geological and geophysical methods provides a significant assessment of earthquake risk for city planning in urban areas.展开更多
Following a brief history and progress of ionospheric research, this paper presents a brief review of the recent developments in the understanding of two major phenomena in low and mid latitude ionosphere—the equator...Following a brief history and progress of ionospheric research, this paper presents a brief review of the recent developments in the understanding of two major phenomena in low and mid latitude ionosphere—the equatorial ionization anomaly(EIA) and involved equatorial plasma fountain(EPF) and ionospheric irregularities. Unlike the easy-to-understand misinterpretations, the EPF involves field perpendicular E×B plasma drift and field-aligned plasma diffusion acting together and plasma flowing in the direction of the resultant at all points along the field lines at all altitudes. The EIA is formed mainly from the removal of plasma from around the equator by the upward E×B drift creating the trough and consequently the crests with small accumulation of plasma at the crests when the crests are within ~±20° magnetic latitudes and no accumulation when they are beyond ~±25° magnetic latitudes. The strong EIA under magnetically active conditions arises from the simultaneous impulsive action of eastward prompt penetration electric field and equatorward neutral wind. Intense ionospheric irregularities develop in the post-sunset bottom-side equatorial ionosphere when it rises to high altitudes, and evolve nonlinearly into the topside. Pre-reversal enhancement(PRE) of the vertical upward E×B drift and its fluctuations amplified during PRE provide the driving force and seed, with neutral wind and gravity waves being the primary sources. At low solar activity especially in summer when fast varying PRE is absent, the slow varying gravity waves including large scale waves(LSW)seem to act as both driver and seed for weak irregularities. At mid latitudes, the irregularities are weak and associated with medium scale traveling ionospheric disturbances(MSTIDs). A low latitude minimum in the occurrence of the irregularities at March equinox predicted by theoretical models is identified. The minimum occurs on the poleward side of the EIA crest and shifts equatorward from ~25° magnetic latitudes at high solar activity to below 17° at low solar activity.展开更多
This study presents an analysis of the quasi-16-day wave(Q16DW)at three stations in the middle latitudes by using a meteor radar chain in conjunction with Aura Microwave Limb Sounder temperature data and MERRA2(Modern...This study presents an analysis of the quasi-16-day wave(Q16DW)at three stations in the middle latitudes by using a meteor radar chain in conjunction with Aura Microwave Limb Sounder temperature data and MERRA2(Modern-Era Retrospective Analysis for Research and Applications,Version 2)reanalysis data from 2008 to 2017.The radar chain consists of three meteor radar stations located at Mohe(MH,53.5°N,122.3°E),Beijing(BJ,40.3°N,116.2°E),and Wuhan(WH,30.5°N,114.6°E).The Q16DW wave exhibits similar seasonal variation in the neutral wind and temperature,and the Q16DW amplitude is generally strong during winter and weak around summer.The Q16DW at BJ was found to have secondary enhancement around September in the zonal wind,which is rarely reported at similar latitudes.The latitudinal variations of the Q16DW in the neutral wind and temperature are quite different.The Q16DW at BJ is the most prominent in both neutral wind components among the three stations and the Q16DW amplitudes at MH and WH are comparable,whereas the wave amplitude in temperature decreases with decreasing latitude.The quasi-geostrophic refractive index squared at the three stations in the period from 2008 to 2017 was revealed.The results indicate that the Q16DW in the mesosphere and lower thermosphere(MLT)at MH has a limited contribution from the lower atmosphere.Around March and October,the Q16DW in the troposphere at BJ can propagate upward into the MLT region,whereas at WH,the contribution to the Q16DW in the MLT region is largely from the mesosphere.展开更多
基金supported by the PolyU RCDSE projects(Nos.P0049221 and P0041304)We would like to express our sincere gratitude to Prof.Feng Li and Dr.Siqi Zhou from Beihang University for providing us with the BH-1 simulant,which served as the crucial reference for the PolyU-1 simulant.We would like to thank the support from the National Natural Science Foundation of China(No.42241103)the Key Research Program of the Institute of Geology and Geophysics,Chinese Academy of Sciences(No.IGGCAS-202101)。
文摘Leading national space exploration agencies and private enterprises are actively engaged in lunar exploration initiatives to accomplish manned lunar landings and establish permanent lunar bases in the forthcoming years.With limited access to lunar surface materials on Earth,lunar regolith simulants are crucial for lunar exploration research.The Chang’e-5(CE-5)samples have been characterized by state-of-the-art laboratory equipment,providing a unique opportunity to develop a high-quality lunar regolith simulant.We have prepared a high-fidelity PolyU-1 simulant by pulverizing,desiccating,sieving,and blending natural mineral materials on Earth based on key physical,mineral,and chemical characteristics of CE-5 samples.The results showed that the simulant has a high degree of consistency with the CE-5 samples in terms of the particle morphology,mineral and chemical composition.Direct shear tests were conducted on the simulant,and the measured internal friction angle and cohesion values can serve as references for determining the mechanical properties of CE-5 lunar regolith.The PolyU-1 simulant can contribute to experimental studies involving lunar regolith,including the assessment of interaction between rovers and lunar regolith,as well as the development of in-situ resource utilization(ISRU)technologies.
基金supported by the Key Research Program of the Institute of Geology and Geophysics,CAS(Nos.IGGCAS-202102 and IGGCAS-201904)the National Natural Science Foundation of China(No.42230111)the CAS Key Technology Talent Program。
文摘After landing in the Utopia Planitia,Tianwen-1 formed the deepest landing crater on Mars,approximately 40 cm deep,exposing precious information about the mechanical properties of Martian soil.We established numerical models for the plume-surface interaction(PSI)and the crater formation based on Computational Fluid Dynamics(CFD)methods and the erosion model modified from Roberts’Theory.Comparative studies of cases were conducted with different nozzle heights and soil mechanical properties.The increase in cohesion and internal friction angle leads to a decrease in erosion rate and maximum crater depth,with the cohesion having a greater impact.The influence of the nozzle height is not clear,as it interacts with the position of the Shock Diamond to jointly control the erosion process.Furthermore,we categorized the evolution of landing craters into the dispersive and the concentrated erosion modes based on the morphological characteristics.Finally,we estimated the upper limits of the Martian soil’s mechanical properties near Tianwen-1 landing site,with the cohesion ranging from 2612 to 2042 Pa and internal friction angle from 25°to 41°.
基金supported by the National Key R&D Program of China (Grant No. 2021YFA0715101)supported by the Chinese 111 Project (Contract No. B20011)+1 种基金the Fundamental Research Funds for the Central Universitiessupported by the Innovation Experimental Class Program
文摘In this work,we aim to investigate the origin of the magnetic carriers in the lunar crust and the intensity of the ancient dynamo field.The magnetization and depth range of magnetic carriers are studied under a weak and a strong magnetic anomaly in Mare Tranquillitatis and in Oceanus Procellarum,respectively,where the surface ages are 3.6 and 3.3 billion years.A sophisticated three-dimensional amplitude inversion software program from a geophysical survey is used to reconstruct the distributions of magnetization in the lunar crust.Because no globally measured surface magnetic field exists for the Moon,a crustal magnetic anomaly model with a grid resolution of 0.2°is used.The depth range of the magnetic source is fixed by the boundary identified by a relative criterion,which is 20%of the recovered maximum magnetization.The central burial depths of the magnetic carriers are approximately 15 km and 25 km under Reiner Gamma and Mare Tranquillitatis,respectively.The volumes of the two magnetic sources are at scales of 104 and 105 km3,respectively.The aforementioned differences may imply a hotter crust under Reiner Gamma than Mare Tranquillitatis by 3.3 billion years.The results support the view that the magma intrusions magnetized by an ancient magnetic field could be the origin of magnetic anomalies under Reiner Gamma and Mare Tranquillitatis.Compared with previous works,the maximum magnetization of 3 A/m under Reiner Gamma supports the intensity of the field being several microteslas.
基金Z.Y.acknowledges the National Natural Science Foundation of China(Grant No.42074211).
文摘Magnetic reconnection and dipolarization are crucial processes driving magnetospheric dynamics,including particle energization,mass circulation,and auroral processes,among others.Recent studies have revealed that these processes at Saturn and Jupiter are fundamentally different from the ones at Earth.The reconnection and dipolarization processes are far more important than previously expected in the dayside magnetodisc of Saturn and potentially Jupiter.Dayside magnetodisc reconnection was directly identified by using Cassini measurements(Guo RL et al.,2018b)and was found to be drizzle-like and rotating in the magnetosphere of Saturn(Delamere et al.,2015b;Yao ZH et al.,2017a;Guo RL et al.,2019).Moreover,magnetic dipolarization could also exist at Saturn’s dayside(Yao ZH et al.,2018),which is fundamentally different from the terrestrial situation.These new results significantly improve our understanding of giant planetary magnetospheric dynamics and provide key insights revealing the physics of planetary aurorae.Here,we briefly review these recent advances and their potential implications for future investigations.
文摘The present issue of Earth and Planetary Physics is dedicated to the near-space neutral and plasma environments of Mars.The issue includes nine papers that present new results on the properties of the Martian exosphere,ionosphere,and magnetosphere,from both observational and modeling points of view.Due to the similarity between the two objects,the issue also includes two additional papers on the near-Venus plasma environment.
文摘During the current interglacial period,conditions on Earth,the homeland of humankind,fostered the emergence of large-scale human cooperation,the unique phenomenon that we call civilization.Since then,humans everywhere on Earth,standing under the vast starlit sky,have thought about and explored our
基金supported by the National Natural Science Foundation of China(Grant 42230111)the Key Research Program of the Institute of Geology and Geophysics,CAS(Mars Mission,Grant IGGCAS-202102)+1 种基金the Key Research Program of the Institute of Geology and Geophysics,CAS(Grant IGGCAS-201904)the CAS Key Technology Talent Program.
文摘The plume-surface interaction(PSI)is a common phenomenon that describes the environment surrounding the landers resulting from the impingement of hot rocket exhaust on the regolith of planetary bodies.The PSI will cause obscuration,erosion of the planetary surface,and high-speed spreading of dust or high-energy ejecta streams,which will induce risks to a safe landing and cause damage to payloads on the landers or to nearby assets.Safe landings and the subsequent scientific goals of deep-space exploration in China call for a comprehensive understanding of the PSI process,including the plume flow mechanics,erosion mechanism,and ejecta dynamics.In addition,the landing crater caused by the plume provides a unique and insightful perspective on the understanding of PSI.In particular,the PSI can be used directly to constrain the composition,structure,and mechanical properties of the surface and subsurface soil.In this study,we conducted a systematic review of the phenomenology and terrestrial tests of PSI:we analyzed the critical factors in the PSI process and compared the differences in PSI phenomena between lunar and Martian conditions;we also reviewed the main erosion mechanisms and the evolution and development of terrestrial tests on PSI.We discuss the problems with PSI,challenges of terrestrial tests,and prospects of PSI,and we show the preliminary results obtained from the landing crater caused by the PSI of Tianwen-1.From analysis of the camera images and digital elevation model reconstructions,we concluded that the landing of Tianwen-1 caused the deepest crater(depth>40 cm)on a planetary surface reported to date and revealed stratigraphic layers in the subsurface of Martian soil.We further constrained the lower bounds of the mechanical properties of Martian soil by a slope stability analysis of the Tianwen-1 landing crater.The PSI may offer promising opportunities to obtain greater insights into planetary science,including the subsurface structure,mineral composition,and properties of soil.
基金supported by the National Natural Science Foundation of China (42030202)。
文摘This study reports the morphological characteristics of anomalous variations in Global Navigation Satellite System Total Electron Content(GNSS-TEC) prior to the strong local earthquakes(EQ) that occurred during the period of 2011-2015.We have analyzed 20 earthquakes of magnitude M> 5.6.A statistical technique is implemented on the data of six GNSS stations located in Tashkent,Kitab,and Maidanak in Uzbekistan,and Islamabad,Multan,Quetta in Pakistan.The results show continuous anomalous variations in TEC during 24 h befo re the occupancy of local earthquakes.It is shown that the precursors before the occurrence of strong earthquakes,in particular of magnitude 5.7,7.7,7.5,7.8 and 7.3 are detected near Eastern Uzbekistan(26 May 2013),Southwestern Pakistan(24 September 2013),Hindukush region of Afghanistan(26 October 2015),and Central Nepal(25 April 2015) and(12 May 2015),respectively.The ionospheric anomalies appearing before the strong earthquakes at six GNSS stations are registered in 14cases(70%) out of 20 selected EQs.It is depicted that anomalies referred to as ionospheric precursors appeared about 1-7 days prior to the occurrence of strong earthquakes.
基金The authors are grateful to the two anonymous reviewers,whose constructive comments have improved this paperThis work was supported by the Special Fund of China Seismic Experimental Site(Nos.2019CSES0103,2018CESE0102 and 2016CESE0203)+1 种基金the National Natural Science Foundation of China(Nos.41630210,41674060 and 41974054)the 13th Five-year Informatization Plan of Chinese Academy of Sciences(grant No.XXH13505-06)。
文摘By using a broadband Lg attenuation model developed for the Tibetan Plateau,we isolate source terms by removing attenuation and site effects from the observed Lg-wave displacement spectra of the M 7.0 earthquake that occurred on August 8,2017,in Jiuzhaigou,China,and its aftershock sequence.Thus,the source parameters,including the scalar seismic moment,comer frequency and stress drop,of these events can be further estimated.The estimated stress drops vary from 47.1 kPa to 7149.6 kPa,with a median value of 59.4 kPa and most values falling between 50 kPa and 75 kPa.The estimated stress drops show significant spatial variations.Lower stress drops were mainly found close to the mainshock and on the seismogenic fault plane with large coseismic slip.In contrast,the highest stress drop was 7.1 MPa for the mainshock,and relatively large stress drops were also found for aftershocks away from the major seismogenic fault and at depths deeper than the zone with large coseismic slip.By using a statistical method,we found self-similarity among some of the aftershocks with a nearly constant stress drop.In contrast,the stress drop increased with the seismic moment for other aftershocks.The amount of stress released during earthquakes is a fundamental characteristic of the earthquake rupture process.As such,the stress drop represents a key parameter for improving our understanding of earthquake source physics.
基金the National Natural Science Foundation of China(grant 41474042)the Key Research Program of the Institute of Geology&Geophysics,Chinese Academy of Sciences(IGGCAS)+1 种基金grant IGGCAS-201904the Computer Simulation Lab,IGGCAS and NSF(grants 0911319 and 1214215).
文摘We have constrained a small-scale,dome-shaped low-velocity structure near the core-mantle boundary(CMB)of Earth beneath Perm(the Perm anomaly)using travel-time analysis and three-dimensional(3-D)forward waveform modeling of seismic data sampling of the mantle.The best-fitting dome-shaped model centers at 60.0°E,50.5°N,and has a height of 400 km and a radius that increases from 200 km at the top to 450 km at the CMB.Its velocity reduction varies from 0%at the top to–3.0%at 240km above the CMB to–3.5%at the CMB.A surrounding 240-km-thick high-velocity D''structure has also been detected.The Perm anomaly may represent a stable smallscale chemical pile in the lowermost mantle,although the hypothesis of a developing mantle plume cannot be ruled out.
基金supported by the National Natural Science Foundation of China(42174217).
文摘Magnetic reconnection processes and their impact on planetary magnetospheric dynamics exhibit significant differences due to differences in upstream solar wind conditions and internal planetary environments.Current understanding of reconnection phenomena at Mercury is rooted in the MESSENGER mission.However,direct detection of reconnection remains rare.Here,we aim to assess the limitations of MESSENGER in detecting reconnection in Mercury’s space and to discuss key issues of reconnection that will be addressed by BepiColombo,including the dynamics of magnetic flux ropes,particle acceleration,density asymmetric reconnection,IMF-driven near-tail structures,and potential modes of magnetospheric convection.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA17010505)
文摘Earth’s near space,located in the region between 20 and 100 km above sea level,is characterized by extreme conditions,such as low temperature,low atmospheric pressure,harsh radiation,and extreme dryness.These conditions are analogous to those found on the surface of Mars and in the atmosphere of Venus,making Earth’s near space a unique natural laboratory for astrobiological research.To address essential astrobiological questions,teams from the Chinese Academy of Sciences(CAS)have developed a scientific balloon platform,the CAS Balloon-Borne Astrobiology Platform(CAS-BAP),to study the effects of near space environmental conditions on the biology and survival strategies of representative organisms in this terrestrial analog.Here,we describe the versatile Biological Samples Exposure Payload(BIOSEP)loaded on the CAS-BAP with respect to its structure and function.The primary function of BIOSEP is to expose appropriate biological specimens to the harsh conditions of near space and subsequently return the exposed samples to laboratories for further analysis.Four successful flight missions in near space from 2019 to 2021 have demonstrated the high reliability and efficiency of the payload in communicating between hardware and software units,recording environmental data,exposing sample containers,protecting samples from external contamination,and recovering samples.Understanding the effects of Earth’s near space conditions on biological specimens will provide valuable insights into the survival strategies of organisms in extreme environments and the search for life beyond Earth.The development of BIOSEP and associated biological exposure experiments will enhance our understanding of the potential for life on Mars and the habitability of the atmospheric regions of other planets in the solar system and beyond.
基金supported by the National Natural Science Foundation of China(Grant No.42304186)China Postdoctoral Science Foundation(2023M743466)+3 种基金the Key Research Program of Chinese Academy of Sciences(Grant No.ZDBS-SSW-TLC00103)the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant No.s IGGCAS-201904,IGGCAS-202102)supported by the International Space Science Institute(ISSI)in Bern and Beijing,through ISSI/ISSI-BJ International Team project“Understanding the Mars Space Environment through Multi-Spacecraft Measurements”(ISSI Team project#23–582ISSIBJ Team project#58).
文摘Using over eight years of Mars Atmosphere and Volatile Evolutio N(MAVEN)data,from November 2014 to May 2023,we have investigated the Martian nightside ionospheric magnetic field distribution under the influence of upstream solar wind drivers,including the interplanetary magnetic field intensity(∣BIMF∣),solar wind dynamic pressure(PS W),solar extreme ultraviolet flux(EUV),and Martian seasons(L s).Our analysis reveals pronounced correlations between magnetic field residuals and both∣BIMF∣and PS W.Correlations observed with EUV flux and Ls were weaker—notably,magnetic field residuals increased during periods of high EUV flux and at Mars perihelion.We find that the IMF penetrates to an altitude of 200 km under a wide range of upstream conditions,penetrating notably deeper under high∣BIMF∣andPSWconditions.Our analysis also indicates that EUV flux and IMF cone angle have minimal impact on IMF penetration depth.Those findings provide useful constraints on the dynamic nature of Martian atmospheric escape processes and their evolution,suggesting that historical solar wind conditions may have facilitated deeper IMF penetration and higher rates of ionospheric escape than are observed now.Moreover,by establishing criteria for magnetic‘quiet’conditions,this study offers new insights into the planet’s magnetic environment under varying solar wind influences,knowledge that should help refine models of the Martian crustal magnetic field.
基金the National Natural Science Foundation of China(42222408)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y2021027)the Key Research Program of the Institute of Geology and Geophysics,CAS(Grant IGGCAS-201904).
文摘Jupiter is one of the top priorities for deep space exploration in China and other countries.The structure of Jupiter’s interior,in particular,is a crucial but still unclear scientific topic.This paper discusses current scientific understanding of Jupiter’s interior by summarizing the history of past and current exploration and data analysis.We review recent space-based and ground-based observation methods and analyze their feasibility.To gain new insight into the internal structure of Jupiter,we propose to study Jupiter’s innards by planetary seismology.Ground-based observation,namely the Jupiter Seismologic Interferometer Polarization Imager(SIPI)in Lenghu,will be developed to obtain the Doppler velocity distribution on the surface of Jupiter and identify oscillation signals.Lenghu has observation conditions that are not only exceptional in China but even in the world,capable of providing novel insight into the interior of Jupiter.This will also be the first study in China of the interior of Jupiter using asteroseismology,which has significant implications for China’s plans to explore Jupiter via spacecraft-mounted instruments.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42030202, 42241115, and 42174204)the China Postdoctoral Science Foundation (Grant No. 2023M743467)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. Y202021)the National Key R&D Program of China (Grant No. 2022YFF0504400)the Opening Funding of the Chinese Academy of Sciences dedicated to the Chinese Meridian Project
文摘Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemispheres is an important but challenging task.In this study,we used a combination of multiple observations and a model simulation to examine the north–south hemispheric difference in the I-T coupling system in the American and Asian sectors during the geomagnetic superstorm that occurred in May 2024.Observations of the total electron content(TEC)showed that the Asian sector had negative storms in the northern hemisphere and positive storms in the southern hemisphere,a process that exacerbated the hemispheric differences in the TEC.However,both hemispheres of the American sector showed negative storms.The thermospheric composition changes also differed between the two sectors,and their variation could partially explain the hemispheric differences caused by positive and negative storms.Moreover,the influence of the thermospheric density change was less than that of the thermospheric composition.Finally,the dynamic effect of the thermospheric wind and the plasma transport processes strongly modulated the north–south differences in the TEC at nighttime in the American and Asian sectors,respectively,during this superstorm.
基金jointly sponsored by the Sinoprobe Laboratory of Chinese Academy of Geological Sciences(Grant No.JKYQN202303)National Natural Science Foundation of China(Grant No.U2344220)the China Geology Survey Project(Grant Nos.DD20230008,DD20240079)。
文摘The South China Block(SCB)was formed through the Neoproterozoic amalgamation of the Yangtze Block(YB),the Cathaysia Block(CB),and the accreted components of the Jiangnan orogenic belt(JNO),it is bounded by the Jiangshan–Shaoxing–Pingxiang fault(JSPF)and the Jiujiang–Shitai–Jishou fault(JSJF)(Yao et al.,2019).The SCB has undergone a series of complex geological events,including Paleozoic orogeny,Mesozoic collisions with the North China Craton(NCC)and the Indochina Block,as well as the intracontinental orogeny,leading to extensive lithospheric modifications and magmatic activities(Zhang H J et al.,2023;Fig.1).
基金the National Natural Science Foundation of China(42030101,42204158)Shanghai Pujiang Program(No.21PJD078)+1 种基金Shanghai Science and Technology Innovation Action Plan(No.21DZ1206100)the Fundamental Research Funds for the Central Universities.
文摘Magnetosonic waves are an important medium for energy transfer in collisionless space plasma.Magnetosonic waves have been widely investigated in the upstream of the bow shock at Mars.These waves are believed to originate from pickup ions or reflected particles.By utilizing MAVEN spacecraft data,we have observed the occurrence of quasi-perpendicularly propagating magnetosonic emissions near the proton gyrofrequency in the Martian magnetotail region.These plasma waves are associated with a significant enhancement of proton and oxygen flux.The excited magnetosonic waves could possibly heat the protons through resonance and facilitate the ionospheric plasma escape.Our results could be helpful to better understand the Mars’magnetospheric dynamics and offer insights into possible energy redistribution between waves and plasma in the Martian nightside magnetosphere.
基金the Special Fund of China Seismic Experimental Site(Nos.2019CSES0103,2018CESE0102 and 2016CESE0203)the National Natural Science Foundation of China(Nos.41630210,41674060,41974054,and 41974061)the“Active Faults Exploration and Seismic Hazard Assessment in Weihai City”funded by Weihai Municipal People's Government.
文摘For city planning and reducing potential earthquake risk,it’s necessary to detect the information of the buried faults in an urban area especially,including the location and activities.An integrated technique with geophysical and geological methods,including the shallow seismic reflection profile,electrical resistivity measurement,geologic borehole section,and exploration trench,was used to detect the Chengnanhe fault,which is one of the two main faults passing through the Weihai urban area in Shandong province,China.The results show that it is a normal fault striking with E-W direction,and it is relatively inactive and stable.By using the thermoluminescence(TL)dating,we found that the Chengnanhe fault initiated in mid-Pleistocene and there was no offset after late Pleistocene.Such an integrated technique with multiple geological and geophysical methods provides a significant assessment of earthquake risk for city planning in urban areas.
基金supported by National Natural Science Foundation of China (41621063, 41774161)the Open Research Project of Large Research Infrastructures of CAS-"Study on the interaction between low/mid-latitude atmosphere and ionosphere based on the Chinese Meridian Project"
文摘Following a brief history and progress of ionospheric research, this paper presents a brief review of the recent developments in the understanding of two major phenomena in low and mid latitude ionosphere—the equatorial ionization anomaly(EIA) and involved equatorial plasma fountain(EPF) and ionospheric irregularities. Unlike the easy-to-understand misinterpretations, the EPF involves field perpendicular E×B plasma drift and field-aligned plasma diffusion acting together and plasma flowing in the direction of the resultant at all points along the field lines at all altitudes. The EIA is formed mainly from the removal of plasma from around the equator by the upward E×B drift creating the trough and consequently the crests with small accumulation of plasma at the crests when the crests are within ~±20° magnetic latitudes and no accumulation when they are beyond ~±25° magnetic latitudes. The strong EIA under magnetically active conditions arises from the simultaneous impulsive action of eastward prompt penetration electric field and equatorward neutral wind. Intense ionospheric irregularities develop in the post-sunset bottom-side equatorial ionosphere when it rises to high altitudes, and evolve nonlinearly into the topside. Pre-reversal enhancement(PRE) of the vertical upward E×B drift and its fluctuations amplified during PRE provide the driving force and seed, with neutral wind and gravity waves being the primary sources. At low solar activity especially in summer when fast varying PRE is absent, the slow varying gravity waves including large scale waves(LSW)seem to act as both driver and seed for weak irregularities. At mid latitudes, the irregularities are weak and associated with medium scale traveling ionospheric disturbances(MSTIDs). A low latitude minimum in the occurrence of the irregularities at March equinox predicted by theoretical models is identified. The minimum occurs on the poleward side of the EIA crest and shifts equatorward from ~25° magnetic latitudes at high solar activity to below 17° at low solar activity.
基金the National Natural Science Foundation of China(through grants 41574142 and 41531070)the National Science Foundation(through grant AGS-1744033).
文摘This study presents an analysis of the quasi-16-day wave(Q16DW)at three stations in the middle latitudes by using a meteor radar chain in conjunction with Aura Microwave Limb Sounder temperature data and MERRA2(Modern-Era Retrospective Analysis for Research and Applications,Version 2)reanalysis data from 2008 to 2017.The radar chain consists of three meteor radar stations located at Mohe(MH,53.5°N,122.3°E),Beijing(BJ,40.3°N,116.2°E),and Wuhan(WH,30.5°N,114.6°E).The Q16DW wave exhibits similar seasonal variation in the neutral wind and temperature,and the Q16DW amplitude is generally strong during winter and weak around summer.The Q16DW at BJ was found to have secondary enhancement around September in the zonal wind,which is rarely reported at similar latitudes.The latitudinal variations of the Q16DW in the neutral wind and temperature are quite different.The Q16DW at BJ is the most prominent in both neutral wind components among the three stations and the Q16DW amplitudes at MH and WH are comparable,whereas the wave amplitude in temperature decreases with decreasing latitude.The quasi-geostrophic refractive index squared at the three stations in the period from 2008 to 2017 was revealed.The results indicate that the Q16DW in the mesosphere and lower thermosphere(MLT)at MH has a limited contribution from the lower atmosphere.Around March and October,the Q16DW in the troposphere at BJ can propagate upward into the MLT region,whereas at WH,the contribution to the Q16DW in the MLT region is largely from the mesosphere.
