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
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
Substorm processes have been studied in detail,and it is well known that interplanetary(IP)shock encountering the terrestrial magnetosphere causes global responses.However,how IP shock compression to the magnetosphere...Substorm processes have been studied in detail,and it is well known that interplanetary(IP)shock encountering the terrestrial magnetosphere causes global responses.However,how IP shock compression to the magnetosphere affects the development of an ongoing substorm remains uninvestigated.Herein,the simultaneous satellite and ground-based auroral evolutions associated with an IP shock impact on the magnetopause during an ongoing substorm on May 7th,2005,were examined.The IMAGE satellite over the Southern Hemisphere captured the global development substorm,which was initiated at 17:38:47 UT.The poleward branch of the nightside auroral oval was fortuitously monitored by an all-sky camera at the Zhongshan Station(-74.5°magnetic latitude,ZHO)in Antarctica.The satellite imager observed continuous brightening and broadening of the nightside auroral oval after the IP shock arrival.The simultaneous ground-based optical aurora measurement displayed the intensification and expansion of a preexisting auroral surge poleward of the aurora oval.The geomagnetic field variations and the instantly increased PC indices indicated an elevated merging rate and enhanced the convection-related DP-2 currents.Therefore,this IP shock transient impact did not significantly change the ongoing development of the substorm,although it meets the magnetospheric precondition hypothesis.展开更多
A diffractive sail is a solar sail whose exposed surface is covered by an advanced diffractive metamaterial film with engineered optical properties. This study examines the optimal performance of a diffractive solar s...A diffractive sail is a solar sail whose exposed surface is covered by an advanced diffractive metamaterial film with engineered optical properties. This study examines the optimal performance of a diffractive solar sail with a Sun-facing attitude in a typical orbit-to-orbit heliocentric transfer. A Sun-facing attitude, which can be passively maintained through the suitable design of the sail shape, is obtained when the sail nominal plane is perpendicular to the Sun–spacecraft line. Unlike an ideal reflective sail, a Sun-facing diffractive sail generates a large transverse thrust component that can be effectively exploited to change the orbital angular momentum. Using a recent thrust model, this study determines the optimal control law of a Sun-facing ideal diffractive sail and simulates the minimum transfer times for a set of interplanetary mission scenarios. It also quantifies the performance difference between Sun-facing diffractive sail and reflective sail. A case study presents the results of a potential mission to the asteroid 16 Psyche.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
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.展开更多
The third order accurate upwind compact difference scheme has been applied to the numerical study of the magnetic reconnection process possibly occurring near the interplanetary current sheet, under the framework of t...The third order accurate upwind compact difference scheme has been applied to the numerical study of the magnetic reconnection process possibly occurring near the interplanetary current sheet, under the framework of the two-dimensional compressible magnetohydrodynamics (MHD). Our results here show that the driven reconnection near the current sheet can occur within 10-30 min for the interplanetary high magnetic Reynolds number, RM =2 000-10 000, the stable magnetic reconnection structure can be formed in hour-order of magnitude, and there are some basic properties such as the multiple X-line reconnections, vortical velocity structures, filament current systems, splitting and collapse of the high-density plasma bulk. These results are helpful in understanding and identifying the magnetic reconnection phenomena near the interplanetary current sheets.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
We analyzed the properties of the solar wind appeared during November 7–8, 1998. Results show that the spaceship ACE spotted a shock (hereinafter referred to as the first shock) at 07:33 UT, November 7. The sheath ap...We analyzed the properties of the solar wind appeared during November 7–8, 1998. Results show that the spaceship ACE spotted a shock (hereinafter referred to as the first shock) at 07:33 UT, November 7. The sheath appeared from the first shock to 22:00 UT November 7. A magnetic cloud-like (MCL) was observed during the period from 22:00 UT November 7 to 11:50 UT, November 8. Another shock was observed at 04:19 UT, November 8 (the second shock). It is apparent that the second shock has entered the rear part of the MCL (MCL_2), though the former part of the MCL (MCL_1) was not affected by the second shock. The main phase of the geomagnetic storm is split into three steps for the convenience of SYM-H index analysis. Step 1 covers the period from the sudden storm commence (SSC) at 08:15 UT, November 7 to the moment of 22:44 UT, November 7. Step 2 starts from 22:44 UT, November 7 and ends at 04:51 UT, November 8. The last step runs from 04:51 UT, November 8 to 06:21 UT, November 8. Step 2 has played a key role in the main development phase of the geomagnetic storm. Analysis of the solar wind properties associated with the main phase shows that the three steps in the main phase have sheath, MCL_1, and MCL_2 as their respective interplanetary source. Specifically, the sheath is covered by the solar wind data from 07:33 UT to 22:00 UT, November 7, MCL1 by the solar wind data from 22:00 UT, November 7 to 04:19 UT November 8, and MCL_2 by the solar wind data from 04:19 UT to 05:57 UT, November 8. MCL_1 had a strong and long lasting so UTh directed magnetic field, allowing it to play a key role in the development of the main phase. MCL_2 made a much smaller contribution to the main development phase, compared with MCL_1.展开更多
Fifty-five suprathermal particle events were selected from WIND observations between 1995 and 1999. Based on systematic analysis on the observational characteristics of these events a two-parameter (the rising time an...Fifty-five suprathermal particle events were selected from WIND observations between 1995 and 1999. Based on systematic analysis on the observational characteristics of these events a two-parameter (the rising time and the flux ratio of electrons to protons in each event) classification method was proposed to classify these events. The three clas-sified classes are (1) impulsive electron events with the flux ratio of electrons to protons being bigger than 1 and rising time being shorter than 200 min, (2) impulsive proton events with the flux ratio being smaller than 1 and rising time being shorter than 200 min, and (3) gradual proton events with the flux ratio being smaller than 1 and the rising time being longer than 200 min. In the past, "impulsive solar electron events" were under in-tense research. However, because the selection standards of their velocity dispersions or pitch-angle distributions were inadequate, statistical surveys of selected events were dif-ferent from each other and even some conclusions were not consistent with the theory, for example, the relation of type-III solar radio bursts to the "impulsive solar electron events". The first class of impulsive electron events are associated with type-III radio bursts and with clear velocity dispersions; therefore they ought to originate from the Sun. The second class of the events, which have short continuance time and usually are not associated with type-III radio bursts and without velocity dispersion, are still far away from inter-planetary shocks and most of them do not one-to-one correspond to corrotating interact-ing regions (CIRs); such events are possible results of local interplanetary magnetic field reconnection or electromagnetic disturbances. Finally, about 2/3 gradual proton events of the third class occur with interplanetary shocks, the delay times of which are almost equal to the rising time. Some of these events can be understood as particle accelerations by shocks.展开更多
In this paper,the optimal interplanetary transfer including planetary escape and capture phases is investigated in the heliocentric frame.Based on primer vector theory,a modi ed cost function with variable coecients i...In this paper,the optimal interplanetary transfer including planetary escape and capture phases is investigated in the heliocentric frame.Based on primer vector theory,a modi ed cost function with variable coecients is developed to re ect the gravitational e ect more precisely.The necessary conditions as well as the transversality conditions of the new cost function are derived to search the optimal solution in xed-time.By introducing the initial and nal coasts,the optimal interplanetary transfer is extended to the time-free situation.Finally,the proposed method is applied to the Earth-Mars and Earth-Asteroid transfer.Comparisons with existing methods show that the proposed method can provide better transfer performances with high eciency.The proposed method extends the application of primer vector theory and provides a fast and accurate reference for preliminary mission design in spacecraft planetary exploration.展开更多
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 Key R&D Program of China(Grant No.2021YFE0106400)the National Scientific Foundation of China(Grant Nos.42120104003,41974185 and 42130210)+3 种基金Shanghai Science and Technology Innovation Action Plan(Grant Nos.21DZ1206100 and 22ZR1481200)SOA Key Laboratory for Polar Science(Grant No.KP201703)Chinese Meridian ProjectMNR Innovative Youth Talents Program(Grant No.12110600000018003921)。
文摘Substorm processes have been studied in detail,and it is well known that interplanetary(IP)shock encountering the terrestrial magnetosphere causes global responses.However,how IP shock compression to the magnetosphere affects the development of an ongoing substorm remains uninvestigated.Herein,the simultaneous satellite and ground-based auroral evolutions associated with an IP shock impact on the magnetopause during an ongoing substorm on May 7th,2005,were examined.The IMAGE satellite over the Southern Hemisphere captured the global development substorm,which was initiated at 17:38:47 UT.The poleward branch of the nightside auroral oval was fortuitously monitored by an all-sky camera at the Zhongshan Station(-74.5°magnetic latitude,ZHO)in Antarctica.The satellite imager observed continuous brightening and broadening of the nightside auroral oval after the IP shock arrival.The simultaneous ground-based optical aurora measurement displayed the intensification and expansion of a preexisting auroral surge poleward of the aurora oval.The geomagnetic field variations and the instantly increased PC indices indicated an elevated merging rate and enhanced the convection-related DP-2 currents.Therefore,this IP shock transient impact did not significantly change the ongoing development of the substorm,although it meets the magnetospheric precondition hypothesis.
基金Open Access funding provided by Università di Pisa within the CRUI-CARE Agreement.
文摘A diffractive sail is a solar sail whose exposed surface is covered by an advanced diffractive metamaterial film with engineered optical properties. This study examines the optimal performance of a diffractive solar sail with a Sun-facing attitude in a typical orbit-to-orbit heliocentric transfer. A Sun-facing attitude, which can be passively maintained through the suitable design of the sail shape, is obtained when the sail nominal plane is perpendicular to the Sun–spacecraft line. Unlike an ideal reflective sail, a Sun-facing diffractive sail generates a large transverse thrust component that can be effectively exploited to change the orbital angular momentum. Using a recent thrust model, this study determines the optimal control law of a Sun-facing ideal diffractive sail and simulates the minimum transfer times for a set of interplanetary mission scenarios. It also quantifies the performance difference between Sun-facing diffractive sail and reflective sail. A case study presents the results of a potential mission to the asteroid 16 Psyche.
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.
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.
基金the National Natural Foundation of China (Grant Nos. 49674243 and 49874040).
文摘The third order accurate upwind compact difference scheme has been applied to the numerical study of the magnetic reconnection process possibly occurring near the interplanetary current sheet, under the framework of the two-dimensional compressible magnetohydrodynamics (MHD). Our results here show that the driven reconnection near the current sheet can occur within 10-30 min for the interplanetary high magnetic Reynolds number, RM =2 000-10 000, the stable magnetic reconnection structure can be formed in hour-order of magnitude, and there are some basic properties such as the multiple X-line reconnections, vortical velocity structures, filament current systems, splitting and collapse of the high-density plasma bulk. These results are helpful in understanding and identifying the magnetic reconnection phenomena near the interplanetary current sheets.
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.
基金supported by National Natural Science Foundation of China (Grant No. 50677020)National High Technology Research and Development Program of China (Grant No. 2009AA12Z150)+2 种基金Science and Technology Diffusion Program of China Meteorological Administration (Grant No.CMATG2007M03)National Standard Program (Grant No. 2007GYB118)Chief Forecaster Program of China Meteorological Administration
文摘We analyzed the properties of the solar wind appeared during November 7–8, 1998. Results show that the spaceship ACE spotted a shock (hereinafter referred to as the first shock) at 07:33 UT, November 7. The sheath appeared from the first shock to 22:00 UT November 7. A magnetic cloud-like (MCL) was observed during the period from 22:00 UT November 7 to 11:50 UT, November 8. Another shock was observed at 04:19 UT, November 8 (the second shock). It is apparent that the second shock has entered the rear part of the MCL (MCL_2), though the former part of the MCL (MCL_1) was not affected by the second shock. The main phase of the geomagnetic storm is split into three steps for the convenience of SYM-H index analysis. Step 1 covers the period from the sudden storm commence (SSC) at 08:15 UT, November 7 to the moment of 22:44 UT, November 7. Step 2 starts from 22:44 UT, November 7 and ends at 04:51 UT, November 8. The last step runs from 04:51 UT, November 8 to 06:21 UT, November 8. Step 2 has played a key role in the main development phase of the geomagnetic storm. Analysis of the solar wind properties associated with the main phase shows that the three steps in the main phase have sheath, MCL_1, and MCL_2 as their respective interplanetary source. Specifically, the sheath is covered by the solar wind data from 07:33 UT to 22:00 UT, November 7, MCL1 by the solar wind data from 22:00 UT, November 7 to 04:19 UT November 8, and MCL_2 by the solar wind data from 04:19 UT to 05:57 UT, November 8. MCL_1 had a strong and long lasting so UTh directed magnetic field, allowing it to play a key role in the development of the main phase. MCL_2 made a much smaller contribution to the main development phase, compared with MCL_1.
基金the National Natural Science Foundation of China (Grant Nos. 10425312, 40574065 and 10333030)the Major State Basic Research Development Program of China (973 program) (Grant No. 2006CB806302)the Chinese Academy of Sciences (Grant No. KJCX2-YW-T04)
文摘Fifty-five suprathermal particle events were selected from WIND observations between 1995 and 1999. Based on systematic analysis on the observational characteristics of these events a two-parameter (the rising time and the flux ratio of electrons to protons in each event) classification method was proposed to classify these events. The three clas-sified classes are (1) impulsive electron events with the flux ratio of electrons to protons being bigger than 1 and rising time being shorter than 200 min, (2) impulsive proton events with the flux ratio being smaller than 1 and rising time being shorter than 200 min, and (3) gradual proton events with the flux ratio being smaller than 1 and the rising time being longer than 200 min. In the past, "impulsive solar electron events" were under in-tense research. However, because the selection standards of their velocity dispersions or pitch-angle distributions were inadequate, statistical surveys of selected events were dif-ferent from each other and even some conclusions were not consistent with the theory, for example, the relation of type-III solar radio bursts to the "impulsive solar electron events". The first class of impulsive electron events are associated with type-III radio bursts and with clear velocity dispersions; therefore they ought to originate from the Sun. The second class of the events, which have short continuance time and usually are not associated with type-III radio bursts and without velocity dispersion, are still far away from inter-planetary shocks and most of them do not one-to-one correspond to corrotating interact-ing regions (CIRs); such events are possible results of local interplanetary magnetic field reconnection or electromagnetic disturbances. Finally, about 2/3 gradual proton events of the third class occur with interplanetary shocks, the delay times of which are almost equal to the rising time. Some of these events can be understood as particle accelerations by shocks.
基金This work was supported by Chang Jiang Scholars Program,the National Natural Science Foundation of China(Grant No.11572038 and No.11772050)Graduate Technological Innovation Project of Beijing Institute of Technology.
文摘In this paper,the optimal interplanetary transfer including planetary escape and capture phases is investigated in the heliocentric frame.Based on primer vector theory,a modi ed cost function with variable coecients is developed to re ect the gravitational e ect more precisely.The necessary conditions as well as the transversality conditions of the new cost function are derived to search the optimal solution in xed-time.By introducing the initial and nal coasts,the optimal interplanetary transfer is extended to the time-free situation.Finally,the proposed method is applied to the Earth-Mars and Earth-Asteroid transfer.Comparisons with existing methods show that the proposed method can provide better transfer performances with high eciency.The proposed method extends the application of primer vector theory and provides a fast and accurate reference for preliminary mission design in spacecraft planetary exploration.