The Mars Ion and Neutral Particle Analyzer(MINPA)is one of the three scientific instruments onboard the Tianwen-1 orbiter to investigate the Martian space environment.During Tianwen-1’s transfer orbit to Mars,the MIN...The Mars Ion and Neutral Particle Analyzer(MINPA)is one of the three scientific instruments onboard the Tianwen-1 orbiter to investigate the Martian space environment.During Tianwen-1’s transfer orbit to Mars,the MINPA was switched on to measure the solar wind ions.Here,we present the first results of the MINPA observations in the solar wind.During cruise,nearly half of the MINPA ion field-of-view(FOV)was blocked by the lander capsule;thus only the solar-wind ions with azimuthal speeds pointing towards the unblocked FOV sectors could be detected.We perform a detailed comparison of the MINPA’s solar wind observations with data from Earth-based missions when MINPA reached its count-rate peak,finding a general consistency of the ion moments between them.The blocking effect due to the lander is evaluated quantitatively under varying solar-wind velocity conditions.Despite the blocking effect,the MINPA’s solar wind measurements during the transfer orbit suggest a good performance.展开更多
自2021年11月以来,火星离子与中性粒子分析仪(Mars Ion and Neutral Particle analyzer,MINPA)持续开展火星空间中离子观测,积累了丰富的科学数据.尽管观测过程中仪器背景信号整体较弱,但在离子信号强度较低的时段,其对离子结构的识别...自2021年11月以来,火星离子与中性粒子分析仪(Mars Ion and Neutral Particle analyzer,MINPA)持续开展火星空间中离子观测,积累了丰富的科学数据.尽管观测过程中仪器背景信号整体较弱,但在离子信号强度较低的时段,其对离子结构的识别和参数计算仍可能产生一定影响.为提高数据的科学适用性,本文系统分析了MINPA离子背景信号的统计特征,揭示其能量分布均匀、方位角与质量组依赖性强、具有随时间演化的特性,并指出不同通道间存在明显差异.基于此,提出了一种根据统计特征的动态背景剔除方法,结合典型观测数据对其有效性进行验证.结果表明,该方法在去除背景干扰、提取真实离子信号方面具有良好效果,特别是在弱信号条件下显著提升了体速度与温度等关键参数的反演精度.本研究为MINPA离子数据的科学研究提供了可靠支撑.展开更多
The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations...The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations from the Mars Ion and Neutral Particle Analyzer onboard the Tianwen-1 orbiter,we calculated the pitch angle distributions of protons in the Martian induced magnetosphere by using information from the magnetohydrodynamically simulated magnetic field,and we statistically analyzed the spatial occurrence pattern of different types of pitch angle distributions.Even though no symmetrical features were seen in the dataset,we found the dominance of the field-aligned distribution type over the energy range from 188 to 6232 eV.Maps of the occurrence rate showed the preferential presence of a trapped-like distribution at the lower altitudes of the surveyed nightside region.Although our results are more or less restricted by the adopted magnetic field,they indicate the complexity of the near-Mars proton pitch angle distributions and infer the possibility of wave–particle interactions in the Martian induced magnetosphere.展开更多
基金supported by the Key Research Program of the Chinese Academy of Sciences(Grant NO.ZDBS-SSW-TLC00103)Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB41000000)+3 种基金NNSFC Grant No.41974170 and 41974196Specialized Research Fund for State Key Laboratories of China,and Pandeng Program of National Space Science Center,Chinese Academy of Sciences.BBT(2019153),YTZ(2017186),WYL(2018177)LHX(2021144)were supported by the Youth Innovation Promotion Associationfunded by the Young Elite Scientists Sponsorship Program by CAST.
文摘The Mars Ion and Neutral Particle Analyzer(MINPA)is one of the three scientific instruments onboard the Tianwen-1 orbiter to investigate the Martian space environment.During Tianwen-1’s transfer orbit to Mars,the MINPA was switched on to measure the solar wind ions.Here,we present the first results of the MINPA observations in the solar wind.During cruise,nearly half of the MINPA ion field-of-view(FOV)was blocked by the lander capsule;thus only the solar-wind ions with azimuthal speeds pointing towards the unblocked FOV sectors could be detected.We perform a detailed comparison of the MINPA’s solar wind observations with data from Earth-based missions when MINPA reached its count-rate peak,finding a general consistency of the ion moments between them.The blocking effect due to the lander is evaluated quantitatively under varying solar-wind velocity conditions.Despite the blocking effect,the MINPA’s solar wind measurements during the transfer orbit suggest a good performance.
文摘自2021年11月以来,火星离子与中性粒子分析仪(Mars Ion and Neutral Particle analyzer,MINPA)持续开展火星空间中离子观测,积累了丰富的科学数据.尽管观测过程中仪器背景信号整体较弱,但在离子信号强度较低的时段,其对离子结构的识别和参数计算仍可能产生一定影响.为提高数据的科学适用性,本文系统分析了MINPA离子背景信号的统计特征,揭示其能量分布均匀、方位角与质量组依赖性强、具有随时间演化的特性,并指出不同通道间存在明显差异.基于此,提出了一种根据统计特征的动态背景剔除方法,结合典型观测数据对其有效性进行验证.结果表明,该方法在去除背景干扰、提取真实离子信号方面具有良好效果,特别是在弱信号条件下显著提升了体速度与温度等关键参数的反演精度.本研究为MINPA离子数据的科学研究提供了可靠支撑.
基金supported by the National Natural Science Foundation of China(Grant No.42241143)the pre-research projects on Civil Aerospace Technologies(No.D020104)funded by the China National Space Administration.
文摘The pitch angle distributions of ions and electrons can be affected by various processes;thus,they can serve as an important indicator of the physical mechanisms driving the dynamics of space plasmas.From observations from the Mars Ion and Neutral Particle Analyzer onboard the Tianwen-1 orbiter,we calculated the pitch angle distributions of protons in the Martian induced magnetosphere by using information from the magnetohydrodynamically simulated magnetic field,and we statistically analyzed the spatial occurrence pattern of different types of pitch angle distributions.Even though no symmetrical features were seen in the dataset,we found the dominance of the field-aligned distribution type over the energy range from 188 to 6232 eV.Maps of the occurrence rate showed the preferential presence of a trapped-like distribution at the lower altitudes of the surveyed nightside region.Although our results are more or less restricted by the adopted magnetic field,they indicate the complexity of the near-Mars proton pitch angle distributions and infer the possibility of wave–particle interactions in the Martian induced magnetosphere.
