Geosynchronous orbit is located in the ring current region,where the energetic particle emission environment challenges the ion deflection design limit of the Energetic Neutral Atom(ENA)imager.Therefore,there is no me...Geosynchronous orbit is located in the ring current region,where the energetic particle emission environment challenges the ion deflection design limit of the Energetic Neutral Atom(ENA)imager.Therefore,there is no measurement record of ENA imaging in this area before.On the basis of possessing the patent of high-energy ion deflection technology,ENA imaging under different Kp index in geosynchronous orbit is simulated.The simulation images show the characteristics of low-altitude ENA emission source and the rough sketch of magnetosphere.Due to the north-south conjugation observation of geosynchronous orbit,the simulated ENA images at different positions all have north-south symmetry.Aiming at the unsolved problems,such as the input source of ring current energetic ions during geomagnetic activities and its evolution process,we analyzed the possible results of ENA imaging combined with in-situ particle measurements in the same satellite,as well as the subversion effect of any north-south asymmetry of ENA map on the inversion model.展开更多
A method is presented for retrieving the magnetospheric ion distribution from En-ergetic Neutral Atom (ENA) measurements made by the NUADU instrument on the TC-2 spacecraft. Based on the already well-established metho...A method is presented for retrieving the magnetospheric ion distribution from En-ergetic Neutral Atom (ENA) measurements made by the NUADU instrument on the TC-2 spacecraft. Based on the already well-established method of constrained lin-ear inversion, an iterance technique suitable for the low count ENA measurements has been developed which is tolerant of the noise background. By the iterance technique, it is possible for the first time to simultaneously retrieve the magneto-spheric ion distribution and the exospheric neutral density, and further to recover global ENA emissions in three dimensions. The technique is applied to a repre-sentative ENA image recorded in energy channel 2 (protons: 50―81 keV) of the NUADU instrument during a major geomagnetic storm and it is, thereby, shown that the retrieval method developed provides a useful tool for extracting ion distribution information from ENA data.展开更多
Comprehensive records are available in ENA data of ring current activity recorded by the NUADU instrument aboard TC-2 on 15 May, 2005 during a major magnetic storm （which incorporated a series of substorms）. Ion flu...Comprehensive records are available in ENA data of ring current activity recorded by the NUADU instrument aboard TC-2 on 15 May, 2005 during a major magnetic storm （which incorporated a series of substorms）. Ion fluxes at 4-min temporal resolution derived from ENA data in the energy ranges 50-81 and 81-158 keV are compared with in situ particle fluxes measured by the LANL-SOPA instruments aboard LANL-01, LANL-02, LANL-97, and LANL-84 （a series of geostationary satellites that encircle the equatorial plane at -6.6 RE）. Also, magnetic fields measured simultaneously by the magetometers aboard GOES-10 and GOES-12 （which are also geostationary satellites） are compared with the particle data. It is demonstrated that ion fluxes in the ring current were enhanced during geomagnetic field tailward stretching in the growth phases of substorms rather than after Earthward directed dipolarization events. This observation, which challenges the existing concept that ring current particles are injected Earthward from the magnetotail following dipolarization events, requires further investigation using a large number of magnetic storm events.展开更多
基金Supported by National Key R&D Program of China(2020YFE0202100)National Mission/Other National Mission:Research on Key Technologies of the Outer Heliospheric Space Exploration System(Y91 Z100102)National Mission/National Major Science and Technology Project:CE-7 Relay Satellite Display Neutral Atom Imager(E16504B31S)。
文摘Geosynchronous orbit is located in the ring current region,where the energetic particle emission environment challenges the ion deflection design limit of the Energetic Neutral Atom(ENA)imager.Therefore,there is no measurement record of ENA imaging in this area before.On the basis of possessing the patent of high-energy ion deflection technology,ENA imaging under different Kp index in geosynchronous orbit is simulated.The simulation images show the characteristics of low-altitude ENA emission source and the rough sketch of magnetosphere.Due to the north-south conjugation observation of geosynchronous orbit,the simulated ENA images at different positions all have north-south symmetry.Aiming at the unsolved problems,such as the input source of ring current energetic ions during geomagnetic activities and its evolution process,we analyzed the possible results of ENA imaging combined with in-situ particle measurements in the same satellite,as well as the subversion effect of any north-south asymmetry of ENA map on the inversion model.
基金the National Natural Science Foundation of China (Grant No. 40674083)Chinese National Key Laboratory research outlay (Grant No. 40523006)SMcKL acknowledges with appreciation the support of Enterprise Ireland
文摘A method is presented for retrieving the magnetospheric ion distribution from En-ergetic Neutral Atom (ENA) measurements made by the NUADU instrument on the TC-2 spacecraft. Based on the already well-established method of constrained lin-ear inversion, an iterance technique suitable for the low count ENA measurements has been developed which is tolerant of the noise background. By the iterance technique, it is possible for the first time to simultaneously retrieve the magneto-spheric ion distribution and the exospheric neutral density, and further to recover global ENA emissions in three dimensions. The technique is applied to a repre-sentative ENA image recorded in energy channel 2 (protons: 50―81 keV) of the NUADU instrument during a major geomagnetic storm and it is, thereby, shown that the retrieval method developed provides a useful tool for extracting ion distribution information from ENA data.
基金the National Natural Science Foundation of China(Grant Nos.41431071,41574152)the National Basic Research Program of China(Grant No.2011CB811404)the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA04060201)
文摘Comprehensive records are available in ENA data of ring current activity recorded by the NUADU instrument aboard TC-2 on 15 May, 2005 during a major magnetic storm （which incorporated a series of substorms）. Ion fluxes at 4-min temporal resolution derived from ENA data in the energy ranges 50-81 and 81-158 keV are compared with in situ particle fluxes measured by the LANL-SOPA instruments aboard LANL-01, LANL-02, LANL-97, and LANL-84 （a series of geostationary satellites that encircle the equatorial plane at -6.6 RE）. Also, magnetic fields measured simultaneously by the magetometers aboard GOES-10 and GOES-12 （which are also geostationary satellites） are compared with the particle data. It is demonstrated that ion fluxes in the ring current were enhanced during geomagnetic field tailward stretching in the growth phases of substorms rather than after Earthward directed dipolarization events. This observation, which challenges the existing concept that ring current particles are injected Earthward from the magnetotail following dipolarization events, requires further investigation using a large number of magnetic storm events.
