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| 1 | Radiation belt electron scattering by whistler-mode chorus in the Jovian magnetosphere: Importance of ambient and wave parameters显示文摘Whistler-mode chorus waves are regarded as an important acceleration mechanism contributing to the formation of relativistic and ultra-relativistic electrons in the Jovian radiation belts. Quantitative determination of the chorus wave driven electron scattering effect in the Jovian magnetosphere requires detailed information of both ambient magnetic field and plasma density and wave spectral property, which however cannot be always readily acquired from observations of existed missions to Jupiter. We therefore perform a comprehensive analysis of the sensitivity of chorus induced electron scattering rates to ambient magnetospheric and wave parameters in the Jovian radiation belts to elaborate to which extent the diffusion coefficients depend on a number of key input parameters. It is found that quasi-linear electron scattering rates by chorus can be strongly affected by the ambient magnetic field intensity, the wave latitudinal coverage, and the peak frequency and bandwidth of the wave spectral distribution in the Jovian magnetosphere, while they only rely slightly on the background plasma density profile and the peak wave normal angle, especially when the wave emissions are confined at lower latitudes. Given the chorus wave amplitude, chorus induced electron scattering rates strongly depend on Jovian L-shell to exhibit a tendency approximately proportional to L_J^3. Our comprehensive analysis explicitly demonstrates the importance of reliable information of both the ambient magnetospheric state and wave distribution property to understanding the dynamic electron evolution in the Jovian radiation belts and therefore has implications for future mission planning to explore the extreme particle radiation environment of Jupiter and its satellites. | BinBin Ni Jing Huang YaSong Ge Jun Cui Yong Wei XuDong Gu Song Fu Zheng Xiang ZhengYu Zhao | 2018 | Earth and Planetary Physics2018,2,1: | 3 |
| 2 | On the source of the quasi-Carrington Rotation periodic magnetic variations on the Martian surface: InSight observations and modeling显示文摘In a recent paper(Luo H et al.,2022),we found that the peak amplitudes of diurnal magnetic variations,measured during martian days(sols)at the InSight landing site,exhibited quasi Carrington-Rotation(qCR)periods at higher eigenmodes of the natural orthogonal components(NOC);these results were based on~664 sols of magnetic field measurements.However,the source of these periodic variations is still unknown.In this paper we introduce the neutral-wind driven ionospheric dynamo current model(e.g.,Lillis et al.,2019)to investigate the source.Four candidates-the draped IMF,electron density/plasma density,the neutral densities,and the electron temperature in the ionosphere with artificial qCR periodicity,are applied in the modeling to find the main factor likely to be causing the observed surface magnetic field variations that exhibit the same qCR periods.Results show that the electron density/plasma density,which controls the total conductivity in the dynamo region,appears to account for the greatest part of the surface qCR variations;its contribution reaches about 67.6%.The draped IMF,the neutral densities,and the electron temperature account,respectively,for only about 12.9%,10.3%,and 9.2%of the variations.Our study implies that the qCR magnetic variations on the Martian surface are due primarily to variations of the dynamo currents caused by the electron density variations.We suggest also that the timevarying fields with the qCR period could be used to probe the Martian interior's electrical conductivity structure to a depth of at least 700 km. | Hao Luo AiMin Du ShaoHua Zhang YaSong Ge Ying Zhang ShuQuan Sun Lin Zhao Lin Tian SongYan Li | 2022 | Earth and Planetary Physics2022,6,3: | 2 |
| 3 | Modeling the Earth's magnetosphere under the influence of solar wind with due northward IMF by the AMR-CESE-MHD model显示文摘We present a newly developed global magnetohydrodynamic(MHD) model to study the responses of the Earth's magnetosphere to the solar wind. The model is established by using the space-time conservation element and solution element(CESE) method in general curvilinear coordinates on a six-component grid system. As a preliminary study, this paper is to present the model's numerical results of the quasi-steady state and the dynamics of the Earth's magnetosphere under steady solar wind flow with due northward interplanetary magnetic field(IMF). The model results are found to be in good agreement with those published by other numerical magnetospheric models. | WANG Juan DU AiMin ZHANG Ying ZHANG TieLong GE YaSong | 2015 | Science China Earth Sciences2015,58,7: | 1 |
| 4 | A case study of large-amplitude ULF waves in the Martian foreshock显示文摘Foreshock ultralow frequency (ULF) waves constitute a significant physical phenomenon in the plasma environment of terrestrial planets. The occurrence of these waves, associated with backstreaming particles reflected and accelerated at the bow shock, implies specific conditions and properties of the shock and its foreshock. Using magnetic field and ion measurements from MAVEN, we report a clear event of ULF waves in the Martian foreshock. The interplanetary magnetic field connected to the Martian bow shock, forming a shock angle of ~51°. Indicating that this was a fast mode wave is the fact that ion density varied in phase with perturbations of the wave field. The peak frequency of the waves was about 0.040 Hz in the spacecraft frame, much lower than the local proton gyrofrequency (~0.088 Hz). The ULF waves had a propagation angle approximately 34° from ambient magnetic field and were accompanied by the whistler mode. The ULF waves displayed left-hand elliptical polarization with respect to the interplanetary magnetic field in the spacecraft frame. All these properties fit very well with foreshock waves excited by interactions between solar wind and backstreaming ions through right-hand beam instability. | LiCan Shan YaSong Ge AiMin Du | 2020 | Earth and Planetary Physics2020,4,1: | 0 |
| 5 | Ion acceleration at dipolarization fronts associated with the interchange instability in Earth's magnetotail显示文摘It has been confirmed that dipolarization fronts(DFs)are the result of the interchange instability in the Earth's magnetotail.In this paper,we use a Hall MHD model to simulate the evolution of the interchange instability that produces DFs along the leading edge.A test particle simulation is performed to study the physical phenomenon of ion acceleration at the DF.The numerical simulation indicates that almost all particles move earthward and dawnward and then drift to the tail.The DF-reflected ion population at the duskside appears earlier as a consequence of the asymmetric Hall electric field.Ions that are distributed in a dawn-dusk asymmetric semicircle behind the DF tend to be accelerated to higher energies(>13.5 keV).These high-energy particles eventually concentrate in the dawnside.Ions experience effective acceleration by the dawnward electric field,while they drift through the dawn flank at the front,toward the tail. | LU HaoYu GE YaSong SUN Chao | 2020 | Science China(Technological Sciences)2020,63,11: | 0 |
| 6 | Along-track Calibration of the Zhurong Rover Magnetometer显示文摘As part of the Chinese Tianwen-1 mission,the Zhurong Rover began its scientific investigation in the southern Utopia Planitia after its successful landing in 15 May,2021.The Zhurong Rover magnetometer(RoMAG),one of the six payloads onboard the rover,includes two identical high-sensitivity triaxial fluxgate magnetometers and can implement mobile magnetic measurements on the surface of Mars.Although a rover magnetic compensation procedure was conducted to remove the magnetic interferences pre-launch,due to the different state of the payloads and electric power system such as the solar panel,an along-track calibration of the magnetometer is necessary to obtain a more accurate Martian magnetic field.Two methods,mast yaw rotations and Rover yaw rotations were utilized separately to determine the Martian horizontal magnetic components.Results show that the Martian horizontal magnetic components determined by the two methods are in good agreement,with the root mean square deviation less than 2.0 nT.The vertical component was also constrained through the pitch movements of the mast by assuming the interferences field distributes like a dipole field.A linear correlation between magnetic field measurements and the solar array currents was derived to calibrate the body field during the regular exploration.We conclude that more accurate measurements could be made when applying the calibration results in the magnetic survey on the surface of Mars. | Hao LUO Aimin DU Yasong GE Ying ZHANG Haiying LI Lin TIAN Kuixiang ZHANG Shuquan SUN Lin ZHAO Zhi LI Xiao FENG | 2024 | Science China Earth Sciences2024,67,2: | 0 |