Vast magnetospheric regions are mapped along the field lines to the narrow latitudinal band of the polar/auroral regions. Therefore monitoring of solar wind energy dissipation into the ionosphere at auroral latitudes ...Vast magnetospheric regions are mapped along the field lines to the narrow latitudinal band of the polar/auroral regions. Therefore monitoring of solar wind energy dissipation into the ionosphere at auroral latitudes gives unique opportunities to study geomagnetic disturbances in their complexity from a relatively well-localized vantage point. Here we introduce and present the current state of a recently proposed science project for coordinated monitoring of high-latitude activity with the EISCAT (European Incoherent Scatter) radar array supported by ground-based magnetometer and optical data and ENA (Energetic Neutral Atom) observation from the CINEMA (Cube-Sat for Ions, Neutrals, Electrons and Magnetic field) satellite system.展开更多
Energetic neutral atoms(ENAs)are produced by the neutralization of energetic ions formed by shock-accelerated gradual solar energetic particle events(SEP).These high-energy ENAs(HENAs)can reach the Earth earlier than ...Energetic neutral atoms(ENAs)are produced by the neutralization of energetic ions formed by shock-accelerated gradual solar energetic particle events(SEP).These high-energy ENAs(HENAs)can reach the Earth earlier than the associated SEPs and thus can provide information about the SEPs at the lower corona.The HENA properties observed at Earth depend on the properties of the coronal mass ejection(CME)-driven shocks that accelerate the SEPs.Using a model of HENA production in a shock-accelerated SEP event,we semi-quantitatively investigate the energy-time spectrum of HENAs depending on the width,propagation speed,and direction of the shock,as well as the density and ion abundances of the lower corona.Compared to the baseline model parameters,the cases with a wider shock width angle or a higher coronal density would increase the HENA flux observed at the Earth,while the case with an Earthpropagating shock shows a softened HENA spectrum.The comparison of expected HENA fluxes in different cases with a flight-proven ENA instrument suggests that solar HENAs can feasibly be monitored with current technologies,which could provide a lead time of 2−3 hours for SEPs at a few MeV.We propose that monitoring of solar HENAs could provide a new method to forecast shock-driven SEP events that are capable of significant space weather impacts on the near-Earth environment.展开更多
The main objective of the Mars Ion and Neutral Particle Analyzer(MINPA)aboard the Chinese Mars Exploration Mission(Tianwen-1)is to study the solar wind-Mars interaction by measuring the ions and energetic neutral atom...The main objective of the Mars Ion and Neutral Particle Analyzer(MINPA)aboard the Chinese Mars Exploration Mission(Tianwen-1)is to study the solar wind-Mars interaction by measuring the ions and energetic neutral atoms(ENAs)near Mars.The MINPA integrates ion and ENA measurements into one sensor head,sharing the same electronics box.The MINPA utilizes a standard toroidal top-hat electrostatic analyzer(ESA)followed by a time of flight(TOF)unit to provide measurement of ions with energies from 2.8 eV to 25.9 keV and ENAs from 50 eV to 3 keV with a base time resolution of 4 seconds.Highly polished silicon single crystal substrates with an Al2O3 film coating are used to ionize the ENAs into positive ions.These ions can then be analyzed by the ESA and TOF,to determine the energy and masses of the ENAs.The MINPA provides a 360°×90°field of view(FOV)with 22.5°×5.4°angular resolution for ion measurement,and a 360°×9.7°FOV with 22.5°×9.7°angular resolution for ENA measurement.The TOF unit combines a-15 kV acceleration high voltage with ultra-thin carbon foils to resolve H+,He2+,He+,O+,O2+and CO2+for ion measurement and to resolve H and O(≥16 amu group)for ENA measurement.Here we present the design principle and describe our ground calibration of the MINPA.展开更多
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
基金supported by the BK21 Plus program through the National Research Foundation(NRF)funded by the Ministry of Education of Korea.
文摘Vast magnetospheric regions are mapped along the field lines to the narrow latitudinal band of the polar/auroral regions. Therefore monitoring of solar wind energy dissipation into the ionosphere at auroral latitudes gives unique opportunities to study geomagnetic disturbances in their complexity from a relatively well-localized vantage point. Here we introduce and present the current state of a recently proposed science project for coordinated monitoring of high-latitude activity with the EISCAT (European Incoherent Scatter) radar array supported by ground-based magnetometer and optical data and ENA (Energetic Neutral Atom) observation from the CINEMA (Cube-Sat for Ions, Neutrals, Electrons and Magnetic field) satellite system.
文摘Energetic neutral atoms(ENAs)are produced by the neutralization of energetic ions formed by shock-accelerated gradual solar energetic particle events(SEP).These high-energy ENAs(HENAs)can reach the Earth earlier than the associated SEPs and thus can provide information about the SEPs at the lower corona.The HENA properties observed at Earth depend on the properties of the coronal mass ejection(CME)-driven shocks that accelerate the SEPs.Using a model of HENA production in a shock-accelerated SEP event,we semi-quantitatively investigate the energy-time spectrum of HENAs depending on the width,propagation speed,and direction of the shock,as well as the density and ion abundances of the lower corona.Compared to the baseline model parameters,the cases with a wider shock width angle or a higher coronal density would increase the HENA flux observed at the Earth,while the case with an Earthpropagating shock shows a softened HENA spectrum.The comparison of expected HENA fluxes in different cases with a flight-proven ENA instrument suggests that solar HENAs can feasibly be monitored with current technologies,which could provide a lead time of 2−3 hours for SEPs at a few MeV.We propose that monitoring of solar HENAs could provide a new method to forecast shock-driven SEP events that are capable of significant space weather impacts on the near-Earth environment.
基金funded by the Chinese National Space Administration.
文摘The main objective of the Mars Ion and Neutral Particle Analyzer(MINPA)aboard the Chinese Mars Exploration Mission(Tianwen-1)is to study the solar wind-Mars interaction by measuring the ions and energetic neutral atoms(ENAs)near Mars.The MINPA integrates ion and ENA measurements into one sensor head,sharing the same electronics box.The MINPA utilizes a standard toroidal top-hat electrostatic analyzer(ESA)followed by a time of flight(TOF)unit to provide measurement of ions with energies from 2.8 eV to 25.9 keV and ENAs from 50 eV to 3 keV with a base time resolution of 4 seconds.Highly polished silicon single crystal substrates with an Al2O3 film coating are used to ionize the ENAs into positive ions.These ions can then be analyzed by the ESA and TOF,to determine the energy and masses of the ENAs.The MINPA provides a 360°×90°field of view(FOV)with 22.5°×5.4°angular resolution for ion measurement,and a 360°×9.7°FOV with 22.5°×9.7°angular resolution for ENA measurement.The TOF unit combines a-15 kV acceleration high voltage with ultra-thin carbon foils to resolve H+,He2+,He+,O+,O2+and CO2+for ion measurement and to resolve H and O(≥16 amu group)for ENA measurement.Here we present the design principle and describe our ground calibration of the MINPA.
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)
