DOI: 10.1002/2017JA024690
Scopus记录号: 2-s2.0-85040249533
论文题名: Global MHD Simulations of the Earth's Bow Shock Shape and Motion Under Variable Solar Wind Conditions
作者: Mejnertsen L. ; Eastwood J.P. ; Hietala H. ; Schwartz S.J. ; Chittenden J.P.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 1 起始页码: 259
结束页码: 271
语种: 英语
英文关键词: bow shock
; global modeling
; magnetohydrodynamics
; magnetosphere
; shock velocity
; spacecraft shock observations
英文摘要: Empirical models of the Earth's bow shock are often used to place in situ measurements in context and to understand the global behavior of the foreshock/bow shock system. They are derived statistically from spacecraft bow shock crossings and typically treat the shock surface as a conic section parameterized according to a uniform solar wind ram pressure, although more complex models exist. Here a global magnetohydrodynamic simulation is used to analyze the variability of the Earth's bow shock under real solar wind conditions. The shape and location of the bow shock is found as a function of time, and this is used to calculate the shock velocity over the shock surface. The results are compared to existing empirical models. Good agreement is found in the variability of the subsolar shock location. However, empirical models fail to reproduce the two-dimensional shape of the shock in the simulation. This is because significant solar wind variability occurs on timescales less than the transit time of a single solar wind phase front over the curved shock surface. Empirical models must therefore be used with care when interpreting spacecraft data, especially when observations are made far from the Sun-Earth line. Further analysis reveals a bias to higher shock speeds when measured by virtual spacecraft. This is attributed to the fact that the spacecraft only observes the shock when it is in motion. This must be accounted for when studying bow shock motion and variability with spacecraft data. ©2017. The Authors.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114870
Appears in Collections: 气候减缓与适应
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作者单位: Space and Atmospheric Physics Group, Blackett Laboratory, Imperial College London, London, United Kingdom; Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA, United States; Plasma Physics Group, Blackett Laboratory, Imperial College London, London, United Kingdom
Recommended Citation:
Mejnertsen L.,Eastwood J.P.,Hietala H.,et al. Global MHD Simulations of the Earth's Bow Shock Shape and Motion Under Variable Solar Wind Conditions[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(1)