DOI: 10.1002/2018JA025265
Scopus记录号: 2-s2.0-85046397560
论文题名: Formation of Plasma Around a Small Meteoroid: Simulation and Theory
作者: Sugar G. ; Oppenheim M.M. ; Dimant Y.S. ; Close S.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 5 起始页码: 4080
结束页码: 4093
语种: 英语
英文关键词: head echo
; meteor plasma
; plasma simulation
英文摘要: High-power large-aperture radars detect meteors by reflecting radio waves off dense plasma that surrounds a hypersonic meteoroid as it ablates in the Earth's atmosphere. If the plasma density profile around the meteoroid is known, the plasma's radar cross section can be used to estimate meteoroid properties such as mass, density, and composition. This paper presents head echo plasma density distributions obtained via two numerical simulations of a small ablating meteoroid and compares the results to an analytical solution found in Dimant and Oppenheim (2017a, https://doi.org/10.1002/2017JA023960, 2017b, https://doi.org/10.1002/2017JA023963). The first simulation allows ablated meteoroid particles to experience only a single collision to match an assumption in the analytical solution, while the second is a more realistic simulation by allowing multiple collisions. The simulation and analytical results exhibit similar plasma density distributions. At distances much less than λT, the average distance an ablated particle travels from the meteoroid before a collision with an atmospheric particle, the plasma density falls off as 1/R, where R is the distance from the meteoroid center. At distances substantially greater than λT, the plasma density profile has an angular dependence, falling off as 1/R2 directly behind the meteoroid, 1/R3 in a plane perpendicular to the meteoroid's path that contains the meteoroid center, and exp[−1.5(R/λT)2/3]/R in front of the meteoroid. When used for calculating meteoroid masses, this new plasma density model can give masses that are orders of magnitude different than masses calculated from a spherically symmetric Gaussian distribution, which has been used to calculate masses in the past. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114037
Appears in Collections: 气候减缓与适应
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作者单位: Department of Aeronautics and Astronautics, Stanford University, Stanford, CA, United States; Center for Space Physics, Boston University, Boston, MA, United States
Recommended Citation:
Sugar G.,Oppenheim M.M.,Dimant Y.S.,et al. Formation of Plasma Around a Small Meteoroid: Simulation and Theory[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(5)