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
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 int...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
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
Two THEMIS(Time History of Events and Macroscale Interactions during Substorms)spacecraft,B and C,began orbiting the Moon in 2011 and have since provided routine measurements of the plasma conditions in the lunar orbi...Two THEMIS(Time History of Events and Macroscale Interactions during Substorms)spacecraft,B and C,began orbiting the Moon in 2011 and have since provided routine measurements of the plasma conditions in the lunar orbit.In this study,we systematically compare these measurements in near-Earth space with solar wind measurements obtained from the Lagrangian 1(L1)point and propagated to the Earth,including measurements in the OMNI database and from the Wind spacecraft.A statistical comparison between THEMIS data and data from the OMNI database from September 2011 to December 2017 showed that the Y and Z components of the magnetic field and the flow speed are generally consistent between the two data sets.The ion number density and the dynamic pressure measured by THEMIS in near-Earth space are lower than those in the OMNI database,suggesting possible variation in the solar wind environment while propagating from the L1 point to near-Earth space.We further show two examples in which near-Earth solar wind measurements are applied in calculating the magnetopause location and in quantifying the magnetic field response to interplanetary shocks.Both examples suggest that using solar wind data from near-Earth space achieves better results than using solar wind data from the L1 point.These results provide validation of THEMIS-B and THEMIS-C as an alternative monitor of the near-Earth solar wind environment.展开更多
Based on cosmic ray data obtained by neutron monitors at the Earth＇s surface, and data on near-relativistic electrons measured by the WIND satellite, as well as on solar X-ray and radio burst data, the solar energeti...Based on cosmic ray data obtained by neutron monitors at the Earth＇s surface, and data on near-relativistic electrons measured by the WIND satellite, as well as on solar X-ray and radio burst data, the solar energetic particle （SEP） event of 2005 January 20 is studied. The results show that this event is a mixed event where the flare is dominant in the acceleration of the SEPs, the interplanetary shock accelerates mainly solar protons with energies below 130 MeV, while the relativistic protons are only accelerated by the solar flare. The interplanetary shock had an obvious acceleration effect on relativistic electrons with energies greater than 2 MeV. It was found that the solar release time for the relativistic protons was about 06：41 UT, while that for the near-relativistic electrons was about 06：39 UT. The latter turned Out to be about 2 rain later than the onset time of the interplanetary type HI burst.展开更多
This paper studies the effects of the solar wind on Jupiter’s magnetosphere. The solar wind parameters are characterized using the Michigan Solar Wind Model (mSWiM) solar wind data propagated to Jupiter from 1997 to ...This paper studies the effects of the solar wind on Jupiter’s magnetosphere. The solar wind parameters are characterized using the Michigan Solar Wind Model (mSWiM) solar wind data propagated to Jupiter from 1997 to 2016. This analysis covers almost solar cycles 23 and 24. Interplanetary fast shocks: Forward shocks (FS), Reverse shocks (RS), and solar wind dynamic pressure were obtained and analyzed during the apparent opposition periods. The fast forward (FS) shocks were predominant during this period. Generally, the solar wind dynamic pressure from FS and RS shocks follows the solar cycles 23 and 24.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 appeared...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
We investigate the magnetospheric response to the 17 March 2015 interplanetary(IP)shock using coordinated groundbased global navigation satellite system(GNSS)total electron content(TEC)observations and global magnetoh...We investigate the magnetospheric response to the 17 March 2015 interplanetary(IP)shock using coordinated groundbased global navigation satellite system(GNSS)total electron content(TEC)observations and global magnetohydrodynamic(MHD)simulations.The TEC measurements reveal distinct perturbations induced by the shock,with the MHD model successfully reproducing the qualitative features of these variations.Our analysis demonstrates:(1)TEC signatures of fast-mode MHD wave propagation from the magnetopause to the inner magnetosphere/plasmasphere within 70 s,generating the strongest TEC enhancements near the subsolar point;(2)subsequent wave reflection between the plasmasphere and magnetopause,producing a secondary TEC peak approximately 2 min after the initial impulse.Comparisons with ground magnetometer data show synchronized two-peak structures,supporting the interpretation of wave reflection dynamics.Although the MHD simulations systematically underestimate TEC magnitudes due to the exclusion of cold plasmaspheric populations,they validate the global patterns and timing of the shock response revealed by the TEC observations.These findings highlight the unique capability of GNSS TEC measurements,with their global coverage and high temporal resolution,to complement in situ observations for studying global-scale magnetospheric wave dynamics and shock impacts.The study underscores the potential of GNSS networks as a powerful tool for probing magnetospheric plasma dynamics,particularly in regions lacking direct satellite instrumentation.展开更多
Aiming at two intense shock events on October 28 and 29,2003,this paper presents a two-step method,which combines synoptic analysis of space weather——“observing”and quantitative prediction——“palpating”,and the...Aiming at two intense shock events on October 28 and 29,2003,this paper presents a two-step method,which combines synoptic analysis of space weather——“observing”and quantitative prediction——“palpating”,and then uses it to test predictions.In the first step of“observing”,on the basis of observations of the solar source surface magnetic field,interplanetary scintillation(IPS)and ACE spacecraft,we find that the propagation of the shocks is asymmetric relative to the normal direction of their solar sources,and the Earth is located near the direction of the fastest speed and the greatest energy of the shocks.As the two fast ejection shock events,the fast explosion of coronal mass of the extremely high temperature,the strong magnetic field,and the high speed background solar wind are also helpful to their rapid propagation.In the second step of“palpating”,we adopt a new membership function of the fast shock events for the ISF method.The predicted results show that for the onset time of the geomagnetic disturbance,the relative errors between the observational and the predicted results are 1.8%and 6.7%;and for the magnetic disturbance magnitude,the relative errors are 4.1%and 3.1%,re-spectively.Furthermore,the comparison among the predicted results of our two-step method with those of five other prevailing methods shows that the two-step method is advantageous.The results tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction precision.展开更多
This paper presents a comparative analysis on the two Solar Proton Events(SPE),which occurred on 14 July 2000(Bastille Day)and 28 October 2003(28OCT03)respectively.It is found that although the peak flux of the latter...This paper presents a comparative analysis on the two Solar Proton Events(SPE),which occurred on 14 July 2000(Bastille Day)and 28 October 2003(28OCT03)respectively.It is found that although the peak flux of the latter seemed to be greater than that of the former based on geostationary observations,the maximum intensities of the energetic protons(>10 MeV and 30 MeV)during the Bastille Day event were all higher than those of the 28OCT03 event according to the interplanetary observations.Further analysis indicated that the quantity of the seed particles,which could be accelerated to the energies exceeding 10 and 30 MeV by the Coronal Mass Ejection(CME)-driven shock on 14 July 2000,was far larger than that of the 28OCT03 event.In the Bastille Day case,when the CME approached to the height around 14 R⊙,the CME-driven shock would reach its maximum capacity in accelerating the solar en-ergetic protons(>100 MeV).In contrast,on 28 October 2003,when CME approached to the height about 58R⊙,the CME-driven shock reached its highest potential in accelerating the solar energetic protons of the same category.At this moment,the peak flux(>100 MeV)was about 155 pfu,which was much lower than 355 pfu measured on 14 July 2000.This demonstrated that in the Bastille Day event,the quantity of the seed particles,which could be accelerated to the energy beyond 100 MeV,was significantly larger than its counterpart in the 28OCT03 case.Therefore,the peak flux of an SPE event depends not only on the interplanetary intensity of the solar energetic particles,but also on the velocity of the associated CME-driven shock,and the quantity of the seed particles as well as on the interplanetary magnetic en-vironment.This paper also reveals that the magnetic sheath associated with ICME on 28 October 2003 captured a large number of solar energetic protons,including those having energy greater than 100 MeV.展开更多
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.
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 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supported by the National Natural Science Foundation of China (grants 41821003 and 41974194)
文摘Two THEMIS(Time History of Events and Macroscale Interactions during Substorms)spacecraft,B and C,began orbiting the Moon in 2011 and have since provided routine measurements of the plasma conditions in the lunar orbit.In this study,we systematically compare these measurements in near-Earth space with solar wind measurements obtained from the Lagrangian 1(L1)point and propagated to the Earth,including measurements in the OMNI database and from the Wind spacecraft.A statistical comparison between THEMIS data and data from the OMNI database from September 2011 to December 2017 showed that the Y and Z components of the magnetic field and the flow speed are generally consistent between the two data sets.The ion number density and the dynamic pressure measured by THEMIS in near-Earth space are lower than those in the OMNI database,suggesting possible variation in the solar wind environment while propagating from the L1 point to near-Earth space.We further show two examples in which near-Earth solar wind measurements are applied in calculating the magnetopause location and in quantifying the magnetic field response to interplanetary shocks.Both examples suggest that using solar wind data from near-Earth space achieves better results than using solar wind data from the L1 point.These results provide validation of THEMIS-B and THEMIS-C as an alternative monitor of the near-Earth solar wind environment.
基金Supported by the National Natural Science Foundation of China.
文摘Based on cosmic ray data obtained by neutron monitors at the Earth＇s surface, and data on near-relativistic electrons measured by the WIND satellite, as well as on solar X-ray and radio burst data, the solar energetic particle （SEP） event of 2005 January 20 is studied. The results show that this event is a mixed event where the flare is dominant in the acceleration of the SEPs, the interplanetary shock accelerates mainly solar protons with energies below 130 MeV, while the relativistic protons are only accelerated by the solar flare. The interplanetary shock had an obvious acceleration effect on relativistic electrons with energies greater than 2 MeV. It was found that the solar release time for the relativistic protons was about 06：41 UT, while that for the near-relativistic electrons was about 06：39 UT. The latter turned Out to be about 2 rain later than the onset time of the interplanetary type HI burst.
文摘This paper studies the effects of the solar wind on Jupiter’s magnetosphere. The solar wind parameters are characterized using the Michigan Solar Wind Model (mSWiM) solar wind data propagated to Jupiter from 1997 to 2016. This analysis covers almost solar cycles 23 and 24. Interplanetary fast shocks: Forward shocks (FS), Reverse shocks (RS), and solar wind dynamic pressure were obtained and analyzed during the apparent opposition periods. The fast forward (FS) shocks were predominant during this period. Generally, the solar wind dynamic pressure from FS and RS shocks follows the solar cycles 23 and 24.
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supported by the Key Innovation Team of China Meteorological Administration“Space Weather Monitoring and Alerting”(Grant No.CMA2024ZD01)the“Ionospheric Forecast and Alerting”Youth Innovation Team(Grant No.CMA2024QN09)the Chinese Meridian Project,and the National Natural Science Foundation of China(Grant No.42374186)。
文摘We investigate the magnetospheric response to the 17 March 2015 interplanetary(IP)shock using coordinated groundbased global navigation satellite system(GNSS)total electron content(TEC)observations and global magnetohydrodynamic(MHD)simulations.The TEC measurements reveal distinct perturbations induced by the shock,with the MHD model successfully reproducing the qualitative features of these variations.Our analysis demonstrates:(1)TEC signatures of fast-mode MHD wave propagation from the magnetopause to the inner magnetosphere/plasmasphere within 70 s,generating the strongest TEC enhancements near the subsolar point;(2)subsequent wave reflection between the plasmasphere and magnetopause,producing a secondary TEC peak approximately 2 min after the initial impulse.Comparisons with ground magnetometer data show synchronized two-peak structures,supporting the interpretation of wave reflection dynamics.Although the MHD simulations systematically underestimate TEC magnitudes due to the exclusion of cold plasmaspheric populations,they validate the global patterns and timing of the shock response revealed by the TEC observations.These findings highlight the unique capability of GNSS TEC measurements,with their global coverage and high temporal resolution,to complement in situ observations for studying global-scale magnetospheric wave dynamics and shock impacts.The study underscores the potential of GNSS networks as a powerful tool for probing magnetospheric plasma dynamics,particularly in regions lacking direct satellite instrumentation.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.40536029,40336053 and 40374056)the International Collaboration Research Team Program of the Chinese Academy of Sciences.
文摘Aiming at two intense shock events on October 28 and 29,2003,this paper presents a two-step method,which combines synoptic analysis of space weather——“observing”and quantitative prediction——“palpating”,and then uses it to test predictions.In the first step of“observing”,on the basis of observations of the solar source surface magnetic field,interplanetary scintillation(IPS)and ACE spacecraft,we find that the propagation of the shocks is asymmetric relative to the normal direction of their solar sources,and the Earth is located near the direction of the fastest speed and the greatest energy of the shocks.As the two fast ejection shock events,the fast explosion of coronal mass of the extremely high temperature,the strong magnetic field,and the high speed background solar wind are also helpful to their rapid propagation.In the second step of“palpating”,we adopt a new membership function of the fast shock events for the ISF method.The predicted results show that for the onset time of the geomagnetic disturbance,the relative errors between the observational and the predicted results are 1.8%and 6.7%;and for the magnetic disturbance magnitude,the relative errors are 4.1%and 3.1%,re-spectively.Furthermore,the comparison among the predicted results of our two-step method with those of five other prevailing methods shows that the two-step method is advantageous.The results tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction precision.
基金Supported by the National Natural Science Foundation of China(Grant Nos.10373017&5067702)
文摘This paper presents a comparative analysis on the two Solar Proton Events(SPE),which occurred on 14 July 2000(Bastille Day)and 28 October 2003(28OCT03)respectively.It is found that although the peak flux of the latter seemed to be greater than that of the former based on geostationary observations,the maximum intensities of the energetic protons(>10 MeV and 30 MeV)during the Bastille Day event were all higher than those of the 28OCT03 event according to the interplanetary observations.Further analysis indicated that the quantity of the seed particles,which could be accelerated to the energies exceeding 10 and 30 MeV by the Coronal Mass Ejection(CME)-driven shock on 14 July 2000,was far larger than that of the 28OCT03 event.In the Bastille Day case,when the CME approached to the height around 14 R⊙,the CME-driven shock would reach its maximum capacity in accelerating the solar en-ergetic protons(>100 MeV).In contrast,on 28 October 2003,when CME approached to the height about 58R⊙,the CME-driven shock reached its highest potential in accelerating the solar energetic protons of the same category.At this moment,the peak flux(>100 MeV)was about 155 pfu,which was much lower than 355 pfu measured on 14 July 2000.This demonstrated that in the Bastille Day event,the quantity of the seed particles,which could be accelerated to the energy beyond 100 MeV,was significantly larger than its counterpart in the 28OCT03 case.Therefore,the peak flux of an SPE event depends not only on the interplanetary intensity of the solar energetic particles,but also on the velocity of the associated CME-driven shock,and the quantity of the seed particles as well as on the interplanetary magnetic en-vironment.This paper also reveals that the magnetic sheath associated with ICME on 28 October 2003 captured a large number of solar energetic protons,including those having energy greater than 100 MeV.
