globalchange  > 影响、适应和脆弱性
DOI: 10.1002/2013JD019619
论文题名:
The angular distribution of energetic electron and X-ray emissions from triggered lightning leaders
作者: Schaal M.M.; Dwyer J.R.; Rassoul H.K.; Hill J.D.; Jordan D.M.; Uman M.A.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期:20
起始页码: 11712
结束页码: 11726
语种: 英语
英文关键词: X-rays from lightning leaders
Scopus关键词: Angular distribution ; Anisotropy ; Electric fields ; Electromagnetic wave emission ; Electron scattering ; Lightning ; Statistical methods ; X ray scattering ; Azimuthal direction ; Degree of anisotropy ; Energetic electron ; International center for lightning research and testing ; Isotropic distributions ; Lightning channel ; Lightning leader ; Triggered lightning ; X rays ; anisotropy ; azimuth ; electric field ; electron ; electron density ; lightning ; spatial distribution ; statistical analysis ; X-ray
英文摘要: We investigate individual X-ray bursts from lightning leaders to determine if energetic electrons at the source (and hence X-rays) are emitted isotropically or with some degree of anisotropy. This study was motivated by the work of Saleh et al. (2009), which found the falloff of X-rays in concentric radial annuli, covering all azimuthal directions in each annulus, from the lightning channel to be most consistent with an isotropic electron source. Here we perform a statistical analysis of angular and spatial distributions of X-rays measured by up to 21 NaI/PMT detectors at the International Center for Lightning Research and Testing site for 21 leader X-ray bursts from five leaders (including four dart-stepped leaders and one dart leader). Two procedures were used to complete this analysis. Procedure 1 found the first-order anisotropy, and procedure 2 tested whether or not the angular distribution was consistent with an isotropic distribution. Because higher-order anisotropies could be present in the data, a distribution that is not isotropic does not necessarily have a significant first-order anisotropy. Using these procedures, we find that at least 11 out of 21 X-ray bursts have a statistically significant first-order anisotropy, and hence those 11 are inconsistent with an isotropic emission. The remaining 10 bursts do not have significant first-order anisotropy. However, of those 10 bursts, 9 are inconsistent with isotropic emission, since they exhibit significant higher-order anisotropies. Since Saleh et al. (2009) did not consider anisotropies in the azimuthal direction, these new measurements of anisotropy do not necessarily contradict that work. Indeed, our analysis supports the finding that the X-ray emissions from lightning are inconsistent with a vertically downward beam. The level of anisotropy of the runaway electrons is important because it provides, in principle, information on the streamer zone in front of the leader and the electric field near the lightning leader tip. Key Points A statistical analysis of angular distributions of x-rays was performed 11 out of 21 x-ray bursts have statistically significant first-order anisotropy Provides information on electric field near the lightning leader tip ©2013. American Geophysical Union. All Rights Reserved.
资助项目: HR0011-08-1-0088 ; HR0011-1-10-1-0061 ; NNX09AJ07H
Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63203
Appears in Collections:影响、适应和脆弱性
气候减缓与适应

Files in This Item:

There are no files associated with this item.


作者单位: Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901, United States; Team QNA, ESC-25, Kennedy Space Center, FL, United States; Department of Electrical and Computer Engineering, University of Florida, Gainesville FL, United States

Recommended Citation:
Schaal M.M.,Dwyer J.R.,Rassoul H.K.,et al. The angular distribution of energetic electron and X-ray emissions from triggered lightning leaders[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(20)
Service
Recommend this item
Sava as my favorate item
Show this item's statistics
Export Endnote File
Google Scholar
Similar articles in Google Scholar
[Schaal M.M.]'s Articles
[Dwyer J.R.]'s Articles
[Rassoul H.K.]'s Articles
百度学术
Similar articles in Baidu Scholar
[Schaal M.M.]'s Articles
[Dwyer J.R.]'s Articles
[Rassoul H.K.]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[Schaal M.M.]‘s Articles
[Dwyer J.R.]‘s Articles
[Rassoul H.K.]‘s Articles
Related Copyright Policies
Null
收藏/分享
所有评论 (0)
暂无评论
 

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.