Shocklets and Short Large Amplitude Magnetic Structures (SLAMS) in the High Mach Foreshock of Venus-猫眼课题宝

DOI：

10.1029/2023gl104610

发表时间：

2023-09

期刊：

Geophysical Research Letters

影响因子：

5.2

通讯作者：

中科院分区：

地球科学1区

文献类型：

作者：

G. Collinson;H. Hietala;Ferdinand Plaschke;T. Karlsson;L. B. Wilson;M. Archer;M. Battarbee;X. Blanco‐Cano;C. Bertucci;David Long;M. Opher;N. Sergis;Claire Gasque;T. Liu;S. Raptis;Sofia Burne;R. Frahm;Tielong Zhang;Y. Futaana

小冲击波和短的大振幅磁结构（SLAMS）是在地球上游前震中常见的陡峭的磁波动。在这里，我们介绍了2009年2月26日金星快车的观测结果，建立了它们在金星稳定状态前震中的存在，建立在过去的研究基础上，该研究发现SLAMS在诱导磁层的实质性扰动期间。金星的结构与地球附近的报告相当。这两个小激波的磁压缩比分别为1.23和1.34，在航天器框架中具有线性极化。3个SLAMS的比率在3.22和4.03之间，其中两个在航天器框架中具有椭圆偏振。统计分析表明，SLAMS与金星上异常高的太阳风阿尔文马赫数（12.5，这次事件）相吻合。因此，虽然我们确定小冲击波和SLAMS可以在稳定的金星前震中形成，但它们可能比地球上更罕见。我们估计其发生率的下限为14%。

Shocklets and short large‐amplitude magnetic structures (SLAMS) are steepened magnetic fluctuations commonly found in Earth's upstream foreshock. Here we present Venus Express observations from the 26th of February 2009 establishing their existence in the steady‐state foreshock of Venus, building on a past study which found SLAMS during a substantial disturbance of the induced magnetosphere. The Venusian structures were comparable to those reported near Earth. The 2 Shocklets had magnetic compression ratios of 1.23 and 1.34 with linear polarization in the spacecraft frame. The 3 SLAMS had ratios between 3.22 and 4.03, two of which with elliptical polarization in the spacecraft frame. Statistical analysis suggests SLAMS coincide with unusually high solar wind Alfvén mach‐number at Venus (12.5, this event). Thus, while we establish Shocklets and SLAMS can form in the stable Venusian foreshock, they may be rarer than at Earth. We estimate a lower limit of their occurrence rate of ≳14%.

Shocklets and Short Large Amplitude Magnetic Structures (SLAMS) in the High Mach Foreshock of Venus

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