火星磁层离子漂移模式的探测。

Detection of magnetospheric ion drift patterns at Mars.

作者信息

Zhang Chi, Nilsson Hans, Ebihara Yusuke, Yamauchi Masatoshi, Persson Moa, Rong Zhaojin, Zhong Jun, Dong Chuanfei, Chen Yuxi, Zhou Xuzhi, Sun Yixin, Harada Yuki, Halekas Jasper, Xu Shaosui, Futaana Yoshifumi, Shi Zhen, Yuan Chongjing, Yun Xiaotong, Fu Song, Gao Jiawei, Holmström Mats, Wei Yong, Barabash Stas

机构信息

Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.

College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China.

出版信息

Nat Commun. 2023 Oct 27;14(1):6866. doi: 10.1038/s41467-023-42630-7.

DOI:10.1038/s41467-023-42630-7

PMID:37891189

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10611764/

Abstract

Mars lacks a global magnetic field, and instead possesses small-scale crustal magnetic fields, making its magnetic environment fundamentally different from intrinsic magnetospheres like those of Earth or Saturn. Here we report the discovery of magnetospheric ion drift patterns, typical of intrinsic magnetospheres, at Mars using measurements from Mars Atmosphere and Volatile EvolutioN mission. Specifically, we observe wedge-like dispersion structures of hydrogen ions exhibiting butterfly-shaped distributions (pitch angle peaks at 22.5°-45° and 135°-157.5°) within the Martian crustal fields, a feature previously observed only in planetary-scale intrinsic magnetospheres. These dispersed structures are the results of drift motions that fundamentally resemble those observed in intrinsic magnetospheres. Our findings indicate that the Martian magnetosphere embodies an intermediate case where both the unmagnetized and magnetized ion behaviors could be observed because of the wide range of strengths and spatial scales of the crustal magnetic fields around Mars.

摘要

火星缺乏全球磁场，而是拥有小规模的地壳磁场，这使得其磁环境与地球或土星等具有固有磁层的行星有着根本的不同。在此，我们利用火星大气与挥发物演化任务的测量数据，报告在火星发现了典型固有磁层的磁层离子漂移模式。具体而言，我们在火星地壳磁场内观测到氢离子呈楔形色散结构，呈现出蝴蝶形分布（俯仰角峰值在22.5°-45°和135°-157.5°），这一特征此前仅在行星尺度的固有磁层中观测到。这些色散结构是漂移运动的结果，其本质上与在固有磁层中观测到的漂移运动相似。我们的研究结果表明，火星磁层体现了一种中间情况，由于火星周围地壳磁场强度和空间尺度范围广泛，未磁化和磁化离子的行为都能被观测到。