气候变化领域集成服务门户(CCPortal): The Photoelectron-Driven Upper Hybrid Instability as the Cause of 150-km Echoes

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DOI	10.1029/2020GL087391
	The Photoelectron-Driven Upper Hybrid Instability as the Cause of 150-km Echoes
	Longley W.J.; Oppenheim M.M.; Pedatella N.M.; Dimant Y.S.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:8
英文摘要	150 kilometer echoes are strong, coherent echoes observed by equatorial radars looking close to perpendicular to Earth's magnetic field. Observations over a day show a distinct necklace pattern with echoes descending from 170 km at sunrise to 130 km at noon, before rising again and disappearing overnight. This paper shows that the upper hybrid instability will convert photoelectron energy into plasma wave energy through inverse Landau damping. Using parameters from a WACCM-X simulation, the upper hybrid wave growth rates over a day show a nearly identical necklace pattern, with bands of positive growth rate following contours of the plasma frequency. Small gaps in altitude with no echoes are explained by thermal electrons Landau damping the instability where the upper hybrid frequency is a multiple of the gyrofrequency. This theory provides a mechanism that likely plays a crucial role in solving a long-standing mystery on the origin of 150-km echoes. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	Damping; Photoelectrons; Photons; Plasma diagnostics; Plasma waves; Thermionic emission; Wave energy conversion; Coherent echoes; Earth's magnetic field; Gyrofrequencies; Landau damping; Photoelectron energy; Plasma frequencies; Thermal electron; Upper-hybrid waves; Plasma stability; detection method; echo sounder; electron; magnetic field; radar; Germany; Landau; Rhineland-Palatinate
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170438
作者单位	Department of Physics and Astronomy, Rice University, Houston, TX, United States; University Corporation for Atmospheric Research, Boulder, CO, United States; Center for Space Physics, Boston University, Boston, MA, United States; High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO, United States
推荐引用方式 GB/T 7714	Longley W.J.,Oppenheim M.M.,Pedatella N.M.,et al. The Photoelectron-Driven Upper Hybrid Instability as the Cause of 150-km Echoes[J],2020,47(8).
APA	Longley W.J.,Oppenheim M.M.,Pedatella N.M.,&Dimant Y.S..(2020).The Photoelectron-Driven Upper Hybrid Instability as the Cause of 150-km Echoes.Geophysical Research Letters,47(8).
MLA	Longley W.J.,et al."The Photoelectron-Driven Upper Hybrid Instability as the Cause of 150-km Echoes".Geophysical Research Letters 47.8(2020).