The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Eart...The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Earth's magnetosphere to the solar wind(SW)impact via simultaneous in situ magnetosheath plasma and magnetic field measurements,X-Ray images of the magnetosheath and magnetic cusps,and UV images of global auroral distributions.Magnetopause deformations associated with magnetosheath high speed jets(HSJs)under a quasi-parallel interplanetary magnetic field condition are studied using a threedimensional(3-D)global hybrid simulation.Soft X-ray intensity calculated based on both physical quantities of solar wind proton and oxygen ions is compared.We obtain key findings concerning deformations at the magnetopause:(1)Magnetopause deformations are highly coherent with the magnetosheath HSJs generated at the quasi-parallel region of the bow shock,(2)X-ray intensities estimated using solar wind h+and self-consistentO7+ions are consistent with each other,(3)Visual spacecraft are employed to check the discrimination ability for capturing magnetopause deformations on Lunar and polar orbits,respectively.The SMILE spacecraft on the polar orbit could be expected to provide opportunities for capturing the global geometry of the magnetopause in the equatorial plane.A striking point is that SMILE has the potential to capture small-scale magnetopause deformations and magnetosheath transients,such as HSJs,at medium altitudes on its orbit.Simulation results also demonstrate that a lunar based imager(e.g.,Lunar Environment heliospheric X-ray Imager,LEXI)is expected to observe a localized brightening of the magnetosheath during HSJ events in the meridian plane.These preliminary results might contribute to the pre-studies for the SMILE and LEXI missions by providing qualitative and quantitative soft X-ray estimates of dayside kinetic processes.展开更多
We conducted 2-D particle-in-cell simulations to investigate the impact of boundary conditions on the evolution of magnetic reconnection. The results demonstrate that the boundary conditions are crucial to this evolut...We conducted 2-D particle-in-cell simulations to investigate the impact of boundary conditions on the evolution of magnetic reconnection. The results demonstrate that the boundary conditions are crucial to this evolution. Specifically, in the cases of traditional periodic boundary(PB) and fully-opened boundary(OB) conditions, the evolutions are quite similar before the system achieves the fastest reconnection rate. However, differences emerge between the two cases afterward. In the PB case, the reconnection electric field experiences a rapid decline and even becomes negative, indicating a reversal of the reconnection process. In contrast, the system maintains a fast reconnection stage in the OB case. Suprathermal electrons are generated near the separatrix and in the exhaust region of both simulation cases. In the electron density depletion layer and the dipolarization front region, a larger proportion of suprathermal electrons are produced in the OB case. Medium-energy electrons are mainly located in the vicinity of the X-line and downstream of the reconnection site in both cases. However, in the OB case, they can also be generated in the electron holes along the separatrix. Before the reverse reconnection stage, no high-energy electrons are present in the PB case. In contrast, about 20% of the electrons in the thin and elongated electron current layer are high-energy in the OB case.展开更多
To the Editor:Bone is a complex tissue that continually undergoes dynamic biological remodeling.However,when bone defects exceed the self-repair threshold,they are regarded as critical-sized bone defects(CBDs),[1]and ...To the Editor:Bone is a complex tissue that continually undergoes dynamic biological remodeling.However,when bone defects exceed the self-repair threshold,they are regarded as critical-sized bone defects(CBDs),[1]and artificial interventions are required to assist the repair process.Implanting three-dimensional(3D)-printed prostheses is a promising candidate for reconstructing limb CBDs.The geometry,pore size,and porosity of these printed prostheses can be customized via a layer-by-layer manufacturing process based on patient-specific model data.[2]Many studies have been conducted to introduce 3D-printed prostheses for repairing CBDs,confirming their biocompatibility,stability,and osteogenesis.However,systematic clinical reports of serial cases are still lacking so far.展开更多
基金supported by the National Key R&D program of China No.2021YFA0718600NNFSC grants 42150105,42188101,and 42274210the Specialized Research Fund for State Key Laboratories of China。
文摘The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Earth's magnetosphere to the solar wind(SW)impact via simultaneous in situ magnetosheath plasma and magnetic field measurements,X-Ray images of the magnetosheath and magnetic cusps,and UV images of global auroral distributions.Magnetopause deformations associated with magnetosheath high speed jets(HSJs)under a quasi-parallel interplanetary magnetic field condition are studied using a threedimensional(3-D)global hybrid simulation.Soft X-ray intensity calculated based on both physical quantities of solar wind proton and oxygen ions is compared.We obtain key findings concerning deformations at the magnetopause:(1)Magnetopause deformations are highly coherent with the magnetosheath HSJs generated at the quasi-parallel region of the bow shock,(2)X-ray intensities estimated using solar wind h+and self-consistentO7+ions are consistent with each other,(3)Visual spacecraft are employed to check the discrimination ability for capturing magnetopause deformations on Lunar and polar orbits,respectively.The SMILE spacecraft on the polar orbit could be expected to provide opportunities for capturing the global geometry of the magnetopause in the equatorial plane.A striking point is that SMILE has the potential to capture small-scale magnetopause deformations and magnetosheath transients,such as HSJs,at medium altitudes on its orbit.Simulation results also demonstrate that a lunar based imager(e.g.,Lunar Environment heliospheric X-ray Imager,LEXI)is expected to observe a localized brightening of the magnetosheath during HSJ events in the meridian plane.These preliminary results might contribute to the pre-studies for the SMILE and LEXI missions by providing qualitative and quantitative soft X-ray estimates of dayside kinetic processes.
基金the support from the Key Research Program of the Chinese Academy of Sciences(No.ZDBSSSW-TLC00105)the National Key R&D Program of China(No.2022YFF0503200)+1 种基金National Natural Science Foundation of China(Nos.41974173 and 42274224)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2019066)。
文摘We conducted 2-D particle-in-cell simulations to investigate the impact of boundary conditions on the evolution of magnetic reconnection. The results demonstrate that the boundary conditions are crucial to this evolution. Specifically, in the cases of traditional periodic boundary(PB) and fully-opened boundary(OB) conditions, the evolutions are quite similar before the system achieves the fastest reconnection rate. However, differences emerge between the two cases afterward. In the PB case, the reconnection electric field experiences a rapid decline and even becomes negative, indicating a reversal of the reconnection process. In contrast, the system maintains a fast reconnection stage in the OB case. Suprathermal electrons are generated near the separatrix and in the exhaust region of both simulation cases. In the electron density depletion layer and the dipolarization front region, a larger proportion of suprathermal electrons are produced in the OB case. Medium-energy electrons are mainly located in the vicinity of the X-line and downstream of the reconnection site in both cases. However, in the OB case, they can also be generated in the electron holes along the separatrix. Before the reverse reconnection stage, no high-energy electrons are present in the PB case. In contrast, about 20% of the electrons in the thin and elongated electron current layer are high-energy in the OB case.
基金supported by the grants from Beijing Municipal Science&Technology Commission(No.Z181100001718195)National Natural Science Foundation of China(No.82172065)+1 种基金Key Clinical Projects of Peking University Third Hospital(No.BYSYZD2022031)Peking University Medicine Sailing Program for Young Scholars’Scientific&Technological Innovation(No.BMU2023YFJHPY015).
文摘To the Editor:Bone is a complex tissue that continually undergoes dynamic biological remodeling.However,when bone defects exceed the self-repair threshold,they are regarded as critical-sized bone defects(CBDs),[1]and artificial interventions are required to assist the repair process.Implanting three-dimensional(3D)-printed prostheses is a promising candidate for reconstructing limb CBDs.The geometry,pore size,and porosity of these printed prostheses can be customized via a layer-by-layer manufacturing process based on patient-specific model data.[2]Many studies have been conducted to introduce 3D-printed prostheses for repairing CBDs,confirming their biocompatibility,stability,and osteogenesis.However,systematic clinical reports of serial cases are still lacking so far.
