The caption of Figure 5 should be:Wind/WAVES type II burst starting around 14 MHz(∼12:05 UT,2017 September 6)and continuing down to∼100 kHz(09:00 UT,2017 September 7).The end time is marked by the short vertical lin...The caption of Figure 5 should be:Wind/WAVES type II burst starting around 14 MHz(∼12:05 UT,2017 September 6)and continuing down to∼100 kHz(09:00 UT,2017 September 7).The end time is marked by the short vertical line with its length indicating the bandwidth(70-130 kHz).The horizontal error bars signify the end time uncertainty.The vertical dashed line marks the SGRE end(06:28 UT,September 7);the horizontal dashed line represents the gamma-ray background.The shock arrival time at 1 au is labeled“SH”(Gopalswamy et al.2018).展开更多
Proper knowledge of the nature of geomagnetic storms and their relationships with the conditions of the space environment at the outer part of the Earth's magnetosphere(bow shock nose) is essential to increase our...Proper knowledge of the nature of geomagnetic storms and their relationships with the conditions of the space environment at the outer part of the Earth's magnetosphere(bow shock nose) is essential to increase our resilience to space weather disturbances. In this article, we present an analysis of the interplanetary magnetic field(IMF) and solar wind parameters relevant to 100 geomagnetic storms in Solar Cycle 24. We revisit the relationship between the minimum disturbance storm time index(Dst_(min)), the minimum southward IMF(B_(S, min)), the maximum solar wind density(N_(SW, max)) and speed(V_(max)), and the lag time between the extrema(dT(B_(z), N),dT(B_(z), V)). We end with a regression formula that fits the data, with a coefficient of determination of 0.58, a root mean square error of 21.30 nT, and a mean absolute error of 15.87 nT. Even though more complex machine learning models can outperform this model, it serves as a theoretically sensible alternative for understanding and forecasting geomagnetic storms.展开更多
The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magne...The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.展开更多
Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of ...Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is<0 in the Northern Hemisphere;in the Southern Hemisphere when it is>0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere.展开更多
Accurate and highly efficient approaches to obtain mission opportunities are still the goals of mission planners of interplanetary explorations.The search for launch opportunities not only determines the specified lau...Accurate and highly efficient approaches to obtain mission opportunities are still the goals of mission planners of interplanetary explorations.The search for launch opportunities not only determines the specified launch window of the mission but also presents the performance requirements for the interplanetary probe and its launch vehicle.An effective method, namely the two-dimensional launch window method, is developed from a completely new perspective to determine all the launch opportunities of the mission in this research.For a fixed launch time,the method to determine all the time windows in the dimension of Time-of-Flight(TOF) is firstly proposed and these time windows represent all the launch opportunities for the given launch time.And then, the two-dimensional launch window method is proposed, which computes the time windows in both the launch time and TOF dimensions to achieve all launch opportunities of the mission.Numerical examples are provided to demonstrate the accuracy and high efficiency of the method.Compared with the widely-used pock-chop plot method, the proposed method reduces the computational time by two orders of magnitude for the same search precision, and thus is especially suitable for the cases involving rapid, high-precision, and/or large-scale searches for mission opportunities.展开更多
The image elements of earth-center and moon-center are obtained by processing the images of earthand moon, these image elements in combination with the inertial attitude information and the moon ephemerisare utilized ...The image elements of earth-center and moon-center are obtained by processing the images of earthand moon, these image elements in combination with the inertial attitude information and the moon ephemerisare utilized to obtain the probe initial position relative to earth, and the Levenberg-Marquardt algorithm is usedto determine the accurate probe position relative to earth, and the probe orbit relative to earth is estimated by u-sing the extended Kalman filter. The autonomous optical navigation algorithm is validated using the digital simu-lation.展开更多
Interplanetary shocks or solar wind pressure pulses have prompted impacts on Earth's magnetospheric and ionospheric environment, especially in causing dynamic changes to the bright aurora in the polar ionosphere. ...Interplanetary shocks or solar wind pressure pulses have prompted impacts on Earth's magnetospheric and ionospheric environment, especially in causing dynamic changes to the bright aurora in the polar ionosphere. The auroral phenomenon associated with shock impingements, referred to as shock aurora, exhibits distinct signatures differing from other geophysical features on the dayside polar ionosphere. Shock aurora provides a direct manifestation of the solar wind–magnetosphere–ionosphere interaction. Imagers onboard satellites can obtain the associated large-scale auroral characteristics during shock impingement on the magnetopause. Therefore, auroral data from satellites are very useful for surveying the comprehensive features of shock aurora and their general evolution. Nonetheless, the ground-based high temporal-spatial resolution all-sky imagers installed at scientific stations play an essential role in revealing medium-and small-scale characteristics of shock aurora. Here, we focus on shock aurora imaging signatures measured by imagers onboard satellites and ground-based all-sky imagers.展开更多
Ground-based observation of Interplanetary Scintillation （IPS） is an important approach of monitoring solar wind speed. We describe both the principle and method of observing the solar wind speed by using the normal...Ground-based observation of Interplanetary Scintillation （IPS） is an important approach of monitoring solar wind speed. We describe both the principle and method of observing the solar wind speed by using the normalized cross-spectrum of simultaneous dualfrequency IPS measurement. The effects of the solar wind properties and the angular size of the scintillation source on the measurement of solar wind speed are investigated by numerical analysis. We carry out a comparison of this method with the traditional single station-single frequency method. We outline a new IPS observation system using this method now under construction at the National Astronomical Observatories, CAS （NAOC）.展开更多
This brief report summarized the latest advances of the interplanetary physics research in China during the period of 2004-2005, made independently by Chinese space physicists and through international collaboration. ...This brief report summarized the latest advances of the interplanetary physics research in China during the period of 2004-2005, made independently by Chinese space physicists and through international collaboration. The report covers all aspects of the interplanetary physics, including theoretical studies, numerical simulation and data analysis.展开更多
Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of stu...Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of study for both solar and space scientists. Considerable progress has been achieved in these aspects by the solar and space physics community of China during 2012–2014, which will be given in this report. The brief report summarizes the research advances of solar corona and interplanetary physics into the following parts: solar wind origin and turbulence, coronal waves and seismology, solar eruptions, solar energetic particle and galactic cosmic ray, magnetic reconnection,Magnetohydrodynamic(MHD) models and their applications, waves and structures in solar wind,propagation of ICMEs/shocks and their arrival time predictions. These research achievements have been achieved by Chinese solar and space scientists independently or via international collaborations.展开更多
Significant progress has been made by Chinese scientists in research of interplanetary physics during the recent two years(2018–2020).These achievements are reflected at least in the following aspects:Activities in s...Significant progress has been made by Chinese scientists in research of interplanetary physics during the recent two years(2018–2020).These achievements are reflected at least in the following aspects:Activities in solar corona and lower solar atmosphere;solar wind and turbulence;filament/prominence,jets,flares,and radio bursts;active regions and solar eruptions;coronal mass ejections and their interplanetary counterparts;other interplanetary structures;space weather prediction methods;magnetic reconnection;Magnetohydrodynamic(MHD)numerical modeling;solar energetic particles,cosmic rays,and Forbush decreases;machine learning methods in space weather and other aspects.More than one hundred and forty papers in the academic journals have been published in these research directions.These fruitful achievements are obtained by Chinese scholars in solar physics and space physics either independently or through international collaborations.They greatly improve people’s understanding of solar activities,solar eruptions,the corresponding space weather effects,and the Sun-Earth relations.Here we will give a very brief review on the research progress.However,it must be pointed out that this paper may not completely cover all achievements in this field due to our limited knowledge.展开更多
Through independent research by the Chinese scientists or their international collaborations,great achievements have been made in interplanetary physics research in China' Mainland during the past two years(2020-2...Through independent research by the Chinese scientists or their international collaborations,great achievements have been made in interplanetary physics research in China' Mainland during the past two years(2020-2022).More than 150 papers have been published in academic journals in this field during this period.These achievements can be grouped into the following areas,at least:(i)solar corona;(ii)solar and interplanetary transient phenomena;(iii)radio bursts;(iv)Magnetohydrodynamic(MHD)numerical modeling;(v)solar energetic particles and cosmic rays.These advances have greatly enriched our understanding of interplanetary physics,i.e.our knowledge of solar activities and solar eruptions,their propagation in the interplanetary space,and the corresponding geoeffects on the Earth.In the sense of application,they have also improved the forecasting of space weather.In this paper we will give a very short review about these advances.展开更多
The scientific objective of solar corona and interplanetary research is the understanding of the various phenomena related to solar activities and their effects on the space environments of the Earth.Great progress ha...The scientific objective of solar corona and interplanetary research is the understanding of the various phenomena related to solar activities and their effects on the space environments of the Earth.Great progress has been made in the study of solar corona and interplanetary physics by the Chinese space physics community during the past years.This paper will give a brief report about the latest progress of the corona and interplanetary research in China during the years of 2010-2012.The paper can be divided into the following parts:solar corona and solar wind.CMEICME, magnetic reconnection,energetic particles,space plasma,space weather numerical modeling by 3D SIP-CESE MHD model,space weather prediction methods,and proposed missions.They constitute the abundant content of study for the complicated phenomena that originate from the solar corona,propagate in interplanetary space,and produce geomagnetic disturbances.All these progresses are acquired by the Chinese space physicists,either independently or through international collaborations.展开更多
Data acquired by imaging relative ionospheric opacity meters(riometers),ionospheric total electron content(TEC)monitors,and three-wavelength auroral imagers at the conjugate Zhongshan station(ZHS)in Antarctica and Yel...Data acquired by imaging relative ionospheric opacity meters(riometers),ionospheric total electron content(TEC)monitors,and three-wavelength auroral imagers at the conjugate Zhongshan station(ZHS)in Antarctica and Yellow River station(YRS)in the Arctic were analyzed to investigate the response of the polar ionosphere to an interplanetary shock event induced by solar flare activity on July 12,2012.After the arrival of the interplanetary shock wave at the magnetosphere at approximately 18:10 UT,significantly enhanced auroral activity was observed by the auroral imagers at the ZHS.Additionally,the polar conjugate observation stations in both hemispheres recorded notable evolution in the two-dimensional movement of cosmic noise absorption.Comparison of the ionospheric TEC data acquired by the conjugate pair showed that the TEC at both sites increased considerably after the interplanetaryshock wave arrived,although the two stations featured different sunlight conditions(polar night in July in the Antarctic region and polar day in the Arctic region).However,the high-frequency(HF)coherent radar data demonstrated that different sourcesmight be responsible for the electron density enhancement in the ionosphere.During the Arctic polar day period in July,the increased electron density over YRS might have been caused by anti-sunward convection of the plasma irregularity,whereas in Antarctica during the polar night,the increased electron density over ZHS might have been caused by energetic particle precipitation from the magnetotail.These different physical processes might be responsible for the different responses of the ionosphere at the two conjugate stations in response to the same interplanetary shock event.展开更多
Data of the daily interplanetary magnetic field (IMF), and the geomagnetic indices (aa, Ap, Kp, and DST) have been used to examine the asymmetry between the solar field north and south of the heliospheric current shee...Data of the daily interplanetary magnetic field (IMF), and the geomagnetic indices (aa, Ap, Kp, and DST) have been used to examine the asymmetry between the solar field north and south of the heliospheric current sheet, over the period (1975-2013). It important to note that during the positive polarity epochs: (T) refers to Toward the South of the heliospheric current sheet (Southern Hemisphere), and (A) refers to Away from North of the heliospheric current sheet (Northern Hemisphere). While, during the negative polarity epochs the opposite will be happened. The present study finds no clear indication of the presence of north-south asymmetry in the field magnitude, and also there is no magnetic solar cycle dependence that is evident. During the considered period, the north-south asymmetry for the considered parameters reaches maximum values around the declining phase or near to the minimum of the solar cycle. The geomagnetic indices have a clear asymmetry during the positive solar magnetic polarity period (qA > 0) and have a northern dominance during cycles (22 & 23) and southern dominance during cycles (21 & 24). From the power spectrum density, the considered parameters showed significant peaks which appeared in the north-south asymmetry but the 10.7 yr solar cycle was absent. In addition, the main periodicity of the asymmetry may be 5.2, 4.0 and 3.3 years that exist in the parameters with higher confidence levels. Finally, one can conclude that the asymmetry of the interplanetary parameters and the geomagnetic indices may provide multiple causes for producing the observed asymmetric modulations of cosmic rays.展开更多
Auroral Kilometric Radiation (AKR) is a common radio emission,which can contribute to the magnetosphere-ionosphereatmosphere co u pling.Similar emissions have been observed in all magnetic planet magnetospheres of the...Auroral Kilometric Radiation (AKR) is a common radio emission,which can contribute to the magnetosphere-ionosphereatmosphere co u pling.Similar emissions have been observed in all magnetic planet magnetospheres of the solar system.In this study,using observations from the FAST satellite from 30 August 1996 to 9 September 2001,the distribution of AKR in altitude=500-4500 km and invariant latitude (|ILAT|)=60°-80°has been analyzed.63045 AKR samples have been identified with~48%(52%) samples on the dayside (nightside).Of considerable interest,there is a distinct MLT asymmetry with the high occurrence rate in MLT=05-08 and 18-22(02-05 and 12-17) in the northern (southern) hemisphere.The distinct MLT asymmetry is associated with the direction of Bxof the interplaneta ry magnetic field.In addition,the occurrence rate on the nightside clearly increases as the AE^(*) index increases.This study further enriches the information and understanding of AKR in the magnetosphere as well as other similar radio emissions.展开更多
The healthcare sector involves many steps to ensure efficient care for patients,such as appointment scheduling,consultation plans,online follow-up,and more.However,existing healthcare mechanisms are unable to facilita...The healthcare sector involves many steps to ensure efficient care for patients,such as appointment scheduling,consultation plans,online follow-up,and more.However,existing healthcare mechanisms are unable to facilitate a large number of patients,as these systems are centralized and hence vulnerable to various issues,including single points of failure,performance bottlenecks,and substantial monetary costs.Furthermore,these mechanisms are unable to provide an efficient mechanism for saving data against unauthorized access.To address these issues,this study proposes a blockchain-based authentication mechanism that authenticates all healthcare stakeholders based on their credentials.Furthermore,also utilize the capabilities of the InterPlanetary File System(IPFS)to store the Electronic Health Record(EHR)in a distributed way.This IPFS platform addresses not only the issue of high data storage costs on blockchain but also the issue of a single point of failure in the traditional centralized data storage model.The simulation results demonstrate that our model outperforms the benchmark schemes and provides an efficient mechanism for managing healthcare sector operations.The results show that it takes approximately 3.5 s for the smart contract to authenticate the node and provide it with the decryption key,which is ultimately used to access the data.The simulation results show that our proposed model outperforms existing solutions in terms of execution time and scalability.The execution time of our model smart contract is around 9000 transactions in just 6.5 s,while benchmark schemes require approximately 7 s for the same number of transactions.展开更多
Magnetic field and plasma measurements in the period of 1975-1981 with 0. 18-h averages from Helios spacecrafts are analyzed. It is discovered that magnetic reconnection phenomena exist in the interplanetary space. By...Magnetic field and plasma measurements in the period of 1975-1981 with 0. 18-h averages from Helios spacecrafts are analyzed. It is discovered that magnetic reconnection phenomena exist in the interplanetary space. By means of the reconstruction of magnetic field configuration in the azimuth angle plane, it is found that the magnetic reconnection event with time scale of the order of day is a significant form of magnetic reconnection phenomena in the interplanetary space, which consists of a mediate body (or a plasma bulk) and two magnetic separator lines. It could originate from coronal mass ejection event or magnetic cloud in the interplanetary space. Numerical simulation has reproduced the basic characteristics of the magnetic reconnection events.展开更多
The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward transmission.This paper quantitatively analyzes the propagation process of the ULF wave triggered by the i...The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward transmission.This paper quantitatively analyzes the propagation process of the ULF wave triggered by the interplanetary shock propagating from inner magnetosphere equatorial plane along magnetic field lines to the top of the ionosphere and below ionosphere propagating process and establishes a relatively complete magnetosphere-ionosphere-atmosphere propagation model which can be used to study the relationship between the amplitude of the ULF waves triggered by the interplanetary shock wave in magnetospheric space and the magnetic effect caused by the ULF waves.After a comparison with recent observations,we found that: in the event during November 7,2004 that an interplanetary shock wave interacted with the magnetosphere,Cluster satellites observed that electric field fluctuations and the band-pass filtered result of ground stations meridional component had similar characteristics.Comparing with the geomagnetic measurement near the footprints,we found that the electric field disturbance in the magnetosphere spread along the ground magnetic field lines in the form of the ULF waves and changed into geomagnetic disturbance.The result reveals that the ULF wave is in contact with the ground geomagnetic observation.The ULF waves couple with ionized components in ionosphere and spread to the ground in the form of electromagnetic waves.In this research,we believe that the magnetosphere,ionosphere and ground magnetic effects caused by interplanetary shock wave are the same physical phenomena responding in different locations.Based on the overall consideration of entire electromagnetic response to the interplanetary shock wave,we found that the correlation between CLUSTER multi-satellite observation and geomagnetic station observation is due to the ULF wave propagated in magnetosphere-ionosphere-atmosphere system,and we quantitatively interpreted this response process.展开更多
An interplanetary magnetic diffusion region was detected by WIND during 0735-0850 UT on May 15, 1997 when the front boundary layer of a magnetic cloud passed through the spacecraft about 190 earth radii upstream of th...An interplanetary magnetic diffusion region was detected by WIND during 0735-0850 UT on May 15, 1997 when the front boundary layer of a magnetic cloud passed through the spacecraft about 190 earth radii upstream of the earth. The main signals of magnetic reconnection processes are: (i) Flow reversal was detected at about 0810 UT. The counter-streaming flows have the speeds of about 65 and 41 km/s, respectively, with an angle of about 140 degree between them. (ii) Hall magnetic field was detected. The Hall fields ?By and +By, perpendicular to the X-Z plane, with their magnitude up to ～7.0 nT, are superposed upon a guide field about 12 nT. (iii) Alfvenic fluctuations are obviously intensified inside the reconnection region; at the front boundary of the reconnection region, a slow-mode-like discontinuity was detected. (iv) Ions are heated intensively inside the reconnection region, with their temperature three times higher than that ahead of the boundary layer; electrons are also heated, with a little enhancement in their temperature. The above observations indicate that magnetic reconnection processes could take place in interplanetary space. Keywords solar wind - interplanetary magnetic clouds - magnetic reconnection展开更多
文摘The caption of Figure 5 should be:Wind/WAVES type II burst starting around 14 MHz(∼12:05 UT,2017 September 6)and continuing down to∼100 kHz(09:00 UT,2017 September 7).The end time is marked by the short vertical line with its length indicating the bandwidth(70-130 kHz).The horizontal error bars signify the end time uncertainty.The vertical dashed line marks the SGRE end(06:28 UT,September 7);the horizontal dashed line represents the gamma-ray background.The shock arrival time at 1 au is labeled“SH”(Gopalswamy et al.2018).
文摘Proper knowledge of the nature of geomagnetic storms and their relationships with the conditions of the space environment at the outer part of the Earth's magnetosphere(bow shock nose) is essential to increase our resilience to space weather disturbances. In this article, we present an analysis of the interplanetary magnetic field(IMF) and solar wind parameters relevant to 100 geomagnetic storms in Solar Cycle 24. We revisit the relationship between the minimum disturbance storm time index(Dst_(min)), the minimum southward IMF(B_(S, min)), the maximum solar wind density(N_(SW, max)) and speed(V_(max)), and the lag time between the extrema(dT(B_(z), N),dT(B_(z), V)). We end with a regression formula that fits the data, with a coefficient of determination of 0.58, a root mean square error of 21.30 nT, and a mean absolute error of 15.87 nT. Even though more complex machine learning models can outperform this model, it serves as a theoretically sensible alternative for understanding and forecasting geomagnetic storms.
基金support from the UK Space Agency under Grant Number ST/T002964/1partly supported by the International Space Science Institute(ISSI)in Bern,through ISSI International Team Project Number 523(“Imaging the Invisible:Unveiling the Global Structure of Earth’s Dynamic Magnetosphere”)。
文摘The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.
基金the National Key Research and Development Program(2022YFF0503700)National Natural Science Foundation of China(42374200)the National Natural Science Foundation of China Basic Science Center(42188101).
文摘Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is<0 in the Northern Hemisphere;in the Southern Hemisphere when it is>0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere.
基金co-supported by the National Natural Science Foundation of China(No.11502300)the Science and Technology on Electro-optic Control Laboratory and the Aerospace Science Foundation of China(No.20165196018)。
文摘Accurate and highly efficient approaches to obtain mission opportunities are still the goals of mission planners of interplanetary explorations.The search for launch opportunities not only determines the specified launch window of the mission but also presents the performance requirements for the interplanetary probe and its launch vehicle.An effective method, namely the two-dimensional launch window method, is developed from a completely new perspective to determine all the launch opportunities of the mission in this research.For a fixed launch time,the method to determine all the time windows in the dimension of Time-of-Flight(TOF) is firstly proposed and these time windows represent all the launch opportunities for the given launch time.And then, the two-dimensional launch window method is proposed, which computes the time windows in both the launch time and TOF dimensions to achieve all launch opportunities of the mission.Numerical examples are provided to demonstrate the accuracy and high efficiency of the method.Compared with the widely-used pock-chop plot method, the proposed method reduces the computational time by two orders of magnitude for the same search precision, and thus is especially suitable for the cases involving rapid, high-precision, and/or large-scale searches for mission opportunities.
文摘The image elements of earth-center and moon-center are obtained by processing the images of earthand moon, these image elements in combination with the inertial attitude information and the moon ephemerisare utilized to obtain the probe initial position relative to earth, and the Levenberg-Marquardt algorithm is usedto determine the accurate probe position relative to earth, and the probe orbit relative to earth is estimated by u-sing the extended Kalman filter. The autonomous optical navigation algorithm is validated using the digital simu-lation.
基金supported by the NSFC (Grant nos. 41431072, 41674169, 41474146, and 41831072)the International Collaboration Supporting Project by the Chinese Arctic and Antarctic Administration (Grant no. IC201608)+1 种基金the National Key R&D Program of China (Grant no. 2018YFC1407304)the Chinese Meridian Project
文摘Interplanetary shocks or solar wind pressure pulses have prompted impacts on Earth's magnetospheric and ionospheric environment, especially in causing dynamic changes to the bright aurora in the polar ionosphere. The auroral phenomenon associated with shock impingements, referred to as shock aurora, exhibits distinct signatures differing from other geophysical features on the dayside polar ionosphere. Shock aurora provides a direct manifestation of the solar wind–magnetosphere–ionosphere interaction. Imagers onboard satellites can obtain the associated large-scale auroral characteristics during shock impingement on the magnetopause. Therefore, auroral data from satellites are very useful for surveying the comprehensive features of shock aurora and their general evolution. Nonetheless, the ground-based high temporal-spatial resolution all-sky imagers installed at scientific stations play an essential role in revealing medium-and small-scale characteristics of shock aurora. Here, we focus on shock aurora imaging signatures measured by imagers onboard satellites and ground-based all-sky imagers.
文摘Ground-based observation of Interplanetary Scintillation （IPS） is an important approach of monitoring solar wind speed. We describe both the principle and method of observing the solar wind speed by using the normalized cross-spectrum of simultaneous dualfrequency IPS measurement. The effects of the solar wind properties and the angular size of the scintillation source on the measurement of solar wind speed are investigated by numerical analysis. We carry out a comparison of this method with the traditional single station-single frequency method. We outline a new IPS observation system using this method now under construction at the National Astronomical Observatories, CAS （NAOC）.
基金Supported by the National Natural Science Foundation of China (40325010)
文摘This brief report summarized the latest advances of the interplanetary physics research in China during the period of 2004-2005, made independently by Chinese space physicists and through international collaboration. The report covers all aspects of the interplanetary physics, including theoretical studies, numerical simulation and data analysis.
文摘Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of study for both solar and space scientists. Considerable progress has been achieved in these aspects by the solar and space physics community of China during 2012–2014, which will be given in this report. The brief report summarizes the research advances of solar corona and interplanetary physics into the following parts: solar wind origin and turbulence, coronal waves and seismology, solar eruptions, solar energetic particle and galactic cosmic ray, magnetic reconnection,Magnetohydrodynamic(MHD) models and their applications, waves and structures in solar wind,propagation of ICMEs/shocks and their arrival time predictions. These research achievements have been achieved by Chinese solar and space scientists independently or via international collaborations.
基金Supported by the B-type Strategic Priority Research Program of Chinese Academy of Sciences(XDB41000000)the National Natural Science Foundation of China(41531073,41731067,41861164026,41874202,41474153)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2016133)Chinese Academy of Sciences Research Fund for Key Development Directions。
文摘Significant progress has been made by Chinese scientists in research of interplanetary physics during the recent two years(2018–2020).These achievements are reflected at least in the following aspects:Activities in solar corona and lower solar atmosphere;solar wind and turbulence;filament/prominence,jets,flares,and radio bursts;active regions and solar eruptions;coronal mass ejections and their interplanetary counterparts;other interplanetary structures;space weather prediction methods;magnetic reconnection;Magnetohydrodynamic(MHD)numerical modeling;solar energetic particles,cosmic rays,and Forbush decreases;machine learning methods in space weather and other aspects.More than one hundred and forty papers in the academic journals have been published in these research directions.These fruitful achievements are obtained by Chinese scholars in solar physics and space physics either independently or through international collaborations.They greatly improve people’s understanding of solar activities,solar eruptions,the corresponding space weather effects,and the Sun-Earth relations.Here we will give a very brief review on the research progress.However,it must be pointed out that this paper may not completely cover all achievements in this field due to our limited knowledge.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDB 41000000)National Natural Science Foundation of China(41531073,41731067,41861164026,41874202,41474153,42074183 and U1738128)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(2016133)Pandeng Program of National Space Science CenterChinese Academy of Sciences。
文摘Through independent research by the Chinese scientists or their international collaborations,great achievements have been made in interplanetary physics research in China' Mainland during the past two years(2020-2022).More than 150 papers have been published in academic journals in this field during this period.These achievements can be grouped into the following areas,at least:(i)solar corona;(ii)solar and interplanetary transient phenomena;(iii)radio bursts;(iv)Magnetohydrodynamic(MHD)numerical modeling;(v)solar energetic particles and cosmic rays.These advances have greatly enriched our understanding of interplanetary physics,i.e.our knowledge of solar activities and solar eruptions,their propagation in the interplanetary space,and the corresponding geoeffects on the Earth.In the sense of application,they have also improved the forecasting of space weather.In this paper we will give a very short review about these advances.
基金Supported by the National Natural Science Foundation of China(40921063,40890162,41074122)the Specialized Research Fund for State Key Laboratories
文摘The scientific objective of solar corona and interplanetary research is the understanding of the various phenomena related to solar activities and their effects on the space environments of the Earth.Great progress has been made in the study of solar corona and interplanetary physics by the Chinese space physics community during the past years.This paper will give a brief report about the latest progress of the corona and interplanetary research in China during the years of 2010-2012.The paper can be divided into the following parts:solar corona and solar wind.CMEICME, magnetic reconnection,energetic particles,space plasma,space weather numerical modeling by 3D SIP-CESE MHD model,space weather prediction methods,and proposed missions.They constitute the abundant content of study for the complicated phenomena that originate from the solar corona,propagate in interplanetary space,and produce geomagnetic disturbances.All these progresses are acquired by the Chinese space physicists,either independently or through international collaborations.
基金the National Key R&D Program of China(Grant no.2018YFF01013706)the National Natural Science Foundation of China(Grant no.41831072)the Top-Notch Young Talents Program of China(Grant no.W02070249).
文摘Data acquired by imaging relative ionospheric opacity meters(riometers),ionospheric total electron content(TEC)monitors,and three-wavelength auroral imagers at the conjugate Zhongshan station(ZHS)in Antarctica and Yellow River station(YRS)in the Arctic were analyzed to investigate the response of the polar ionosphere to an interplanetary shock event induced by solar flare activity on July 12,2012.After the arrival of the interplanetary shock wave at the magnetosphere at approximately 18:10 UT,significantly enhanced auroral activity was observed by the auroral imagers at the ZHS.Additionally,the polar conjugate observation stations in both hemispheres recorded notable evolution in the two-dimensional movement of cosmic noise absorption.Comparison of the ionospheric TEC data acquired by the conjugate pair showed that the TEC at both sites increased considerably after the interplanetaryshock wave arrived,although the two stations featured different sunlight conditions(polar night in July in the Antarctic region and polar day in the Arctic region).However,the high-frequency(HF)coherent radar data demonstrated that different sourcesmight be responsible for the electron density enhancement in the ionosphere.During the Arctic polar day period in July,the increased electron density over YRS might have been caused by anti-sunward convection of the plasma irregularity,whereas in Antarctica during the polar night,the increased electron density over ZHS might have been caused by energetic particle precipitation from the magnetotail.These different physical processes might be responsible for the different responses of the ionosphere at the two conjugate stations in response to the same interplanetary shock event.
文摘Data of the daily interplanetary magnetic field (IMF), and the geomagnetic indices (aa, Ap, Kp, and DST) have been used to examine the asymmetry between the solar field north and south of the heliospheric current sheet, over the period (1975-2013). It important to note that during the positive polarity epochs: (T) refers to Toward the South of the heliospheric current sheet (Southern Hemisphere), and (A) refers to Away from North of the heliospheric current sheet (Northern Hemisphere). While, during the negative polarity epochs the opposite will be happened. The present study finds no clear indication of the presence of north-south asymmetry in the field magnitude, and also there is no magnetic solar cycle dependence that is evident. During the considered period, the north-south asymmetry for the considered parameters reaches maximum values around the declining phase or near to the minimum of the solar cycle. The geomagnetic indices have a clear asymmetry during the positive solar magnetic polarity period (qA > 0) and have a northern dominance during cycles (22 & 23) and southern dominance during cycles (21 & 24). From the power spectrum density, the considered parameters showed significant peaks which appeared in the north-south asymmetry but the 10.7 yr solar cycle was absent. In addition, the main periodicity of the asymmetry may be 5.2, 4.0 and 3.3 years that exist in the parameters with higher confidence levels. Finally, one can conclude that the asymmetry of the interplanetary parameters and the geomagnetic indices may provide multiple causes for producing the observed asymmetric modulations of cosmic rays.
基金supported by the National Natural Science Foundation of China grants 42230209,42374215,42304183,72342001,71931003 and 72061147004the Scientific Research Fund of Hunan Provincial Education Department grants 21A0212the Science and Technology Innovation Program of Hunan Province under Grants 2022RC4025,2023JJ50312,2023JJ50010.
文摘Auroral Kilometric Radiation (AKR) is a common radio emission,which can contribute to the magnetosphere-ionosphereatmosphere co u pling.Similar emissions have been observed in all magnetic planet magnetospheres of the solar system.In this study,using observations from the FAST satellite from 30 August 1996 to 9 September 2001,the distribution of AKR in altitude=500-4500 km and invariant latitude (|ILAT|)=60°-80°has been analyzed.63045 AKR samples have been identified with~48%(52%) samples on the dayside (nightside).Of considerable interest,there is a distinct MLT asymmetry with the high occurrence rate in MLT=05-08 and 18-22(02-05 and 12-17) in the northern (southern) hemisphere.The distinct MLT asymmetry is associated with the direction of Bxof the interplaneta ry magnetic field.In addition,the occurrence rate on the nightside clearly increases as the AE^(*) index increases.This study further enriches the information and understanding of AKR in the magnetosphere as well as other similar radio emissions.
基金supported by the Ongoing Research Funding program(ORF-2025-636),King Saud University,Riyadh,Saudi Arabia.
文摘The healthcare sector involves many steps to ensure efficient care for patients,such as appointment scheduling,consultation plans,online follow-up,and more.However,existing healthcare mechanisms are unable to facilitate a large number of patients,as these systems are centralized and hence vulnerable to various issues,including single points of failure,performance bottlenecks,and substantial monetary costs.Furthermore,these mechanisms are unable to provide an efficient mechanism for saving data against unauthorized access.To address these issues,this study proposes a blockchain-based authentication mechanism that authenticates all healthcare stakeholders based on their credentials.Furthermore,also utilize the capabilities of the InterPlanetary File System(IPFS)to store the Electronic Health Record(EHR)in a distributed way.This IPFS platform addresses not only the issue of high data storage costs on blockchain but also the issue of a single point of failure in the traditional centralized data storage model.The simulation results demonstrate that our model outperforms the benchmark schemes and provides an efficient mechanism for managing healthcare sector operations.The results show that it takes approximately 3.5 s for the smart contract to authenticate the node and provide it with the decryption key,which is ultimately used to access the data.The simulation results show that our proposed model outperforms existing solutions in terms of execution time and scalability.The execution time of our model smart contract is around 9000 transactions in just 6.5 s,while benchmark schemes require approximately 7 s for the same number of transactions.
基金Project supported by the National Natural Science Foundation of China.
文摘Magnetic field and plasma measurements in the period of 1975-1981 with 0. 18-h averages from Helios spacecrafts are analyzed. It is discovered that magnetic reconnection phenomena exist in the interplanetary space. By means of the reconstruction of magnetic field configuration in the azimuth angle plane, it is found that the magnetic reconnection event with time scale of the order of day is a significant form of magnetic reconnection phenomena in the interplanetary space, which consists of a mediate body (or a plasma bulk) and two magnetic separator lines. It could originate from coronal mass ejection event or magnetic cloud in the interplanetary space. Numerical simulation has reproduced the basic characteristics of the magnetic reconnection events.
基金supported by the key project of National Natural Science Foundation of China (Grant No. 40831061)the Specialized Research Fund for State Key Laboratories of China
文摘The ultra low frequency (ULF) wave in magnetosphere can act as an important means for solar wind energy inward transmission.This paper quantitatively analyzes the propagation process of the ULF wave triggered by the interplanetary shock propagating from inner magnetosphere equatorial plane along magnetic field lines to the top of the ionosphere and below ionosphere propagating process and establishes a relatively complete magnetosphere-ionosphere-atmosphere propagation model which can be used to study the relationship between the amplitude of the ULF waves triggered by the interplanetary shock wave in magnetospheric space and the magnetic effect caused by the ULF waves.After a comparison with recent observations,we found that: in the event during November 7,2004 that an interplanetary shock wave interacted with the magnetosphere,Cluster satellites observed that electric field fluctuations and the band-pass filtered result of ground stations meridional component had similar characteristics.Comparing with the geomagnetic measurement near the footprints,we found that the electric field disturbance in the magnetosphere spread along the ground magnetic field lines in the form of the ULF waves and changed into geomagnetic disturbance.The result reveals that the ULF wave is in contact with the ground geomagnetic observation.The ULF waves couple with ionized components in ionosphere and spread to the ground in the form of electromagnetic waves.In this research,we believe that the magnetosphere,ionosphere and ground magnetic effects caused by interplanetary shock wave are the same physical phenomena responding in different locations.Based on the overall consideration of entire electromagnetic response to the interplanetary shock wave,we found that the correlation between CLUSTER multi-satellite observation and geomagnetic station observation is due to the ULF wave propagated in magnetosphere-ionosphere-atmosphere system,and we quantitatively interpreted this response process.
文摘An interplanetary magnetic diffusion region was detected by WIND during 0735-0850 UT on May 15, 1997 when the front boundary layer of a magnetic cloud passed through the spacecraft about 190 earth radii upstream of the earth. The main signals of magnetic reconnection processes are: (i) Flow reversal was detected at about 0810 UT. The counter-streaming flows have the speeds of about 65 and 41 km/s, respectively, with an angle of about 140 degree between them. (ii) Hall magnetic field was detected. The Hall fields ?By and +By, perpendicular to the X-Z plane, with their magnitude up to ～7.0 nT, are superposed upon a guide field about 12 nT. (iii) Alfvenic fluctuations are obviously intensified inside the reconnection region; at the front boundary of the reconnection region, a slow-mode-like discontinuity was detected. (iv) Ions are heated intensively inside the reconnection region, with their temperature three times higher than that ahead of the boundary layer; electrons are also heated, with a little enhancement in their temperature. The above observations indicate that magnetic reconnection processes could take place in interplanetary space. Keywords solar wind - interplanetary magnetic clouds - magnetic reconnection
