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DOI | 10.1029/2019GL083753 |
On the Role of Reduced Air Density Along the Lightning Leader Path to Ground in Increasing X-Ray Production Relative to Normal Atmospheric Conditions | |
Tran, M. D.1,2; Kereszy, I1,3; Rakov, V. A.1,4; Dwyer, J. R.5,6 | |
2019-08-16 | |
发表期刊 | GEOPHYSICAL RESEARCH LETTERS |
ISSN | 0094-8276 |
EISSN | 1944-8007 |
出版年 | 2019 |
卷号 | 46期号:15页码:9252-9260 |
文章类型 | Article |
语种 | 英语 |
国家 | USA; Russia |
英文摘要 | Mallick et al. (2012, https://doi.org/10.1029/2012JD017555) discovered that subsequent-stroke leaders in natural negative lightning could be more prolific producers of hard X-rays and gamma rays than the first-stroke leader in the same flash. However, they had no optical records to confirm that their subsequent leaders followed the same path to ground as the first leader, as opposed to forging a new path to ground through cold air. In this paper, we present new observations, including optical data, showing that a second stroke produced more detectable X-ray pulses than the first stroke, with both strokes following the same channel to ground. Additionally, we present data for the fifth stroke from a different flash, which show the occurrence of X-ray emission at the onset of the common streamer zone between the hot channels of the downward negative dart-stepped leader and upward positive connecting leader. However, there were no detectable X-rays associated with negative leader steps. Plain Language Summary: Cloud-to-ground lightning flashes are each typically composed of 3 to 5 strokes. First stroke necessarily develops in virgin (cold) air, while subsequent strokes often retrace the remnants of the channel(s) of preceding stroke(s). Lightning is known to produce hard X-rays during the initial (leader) stage of each of its strokes. Traditionally, first-stroke leaders were thought to be the main producers of X-rays, and subsequent-stroke leaders (developing in warm, low-density air) were thought to be less active X-ray producers. Mallick et al. (2012) observed subsequent-stroke leaders that were more prolific producers of X-rays than the first-stroke leader in the same flash. However, they had no high-speed video images to confirm that their subsequent leaders followed the same path to ground as the first leader, as opposed to forging a new path to ground through cold air. We present new observations, including high-speed video images, showing that a second stroke produced more detectable X-ray pulses than the first stroke, with both strokes following the same channel to ground. Additionally, we present data for a subsequent stroke from a different flash, which show the rarely observed occurrence of significant X-ray emission at the time of attachment of that stroke to the ground. |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000483812500070 |
WOS关键词 | COLLISIONS |
WOS类目 | Geosciences, Multidisciplinary |
WOS研究方向 | Geology |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/186076 |
专题 | 气候变化 |
作者单位 | 1.Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA; 2.Rhombus Power Inc, Moffett Field, CA USA; 3.Univ Florida, Dept Phys, Gainesville, FL 32611 USA; 4.Natl Res Univ Higher Sch Econ, Moscow Inst Elect & Math, Moscow, Russia; 5.Univ New Hampshire, Dept Phys, Durham, NH 03824 USA; 6.Univ New Hampshire, Space Sci Ctr EOS, Durham, NH 03824 USA |
推荐引用方式 GB/T 7714 | Tran, M. D.,Kereszy, I,Rakov, V. A.,et al. On the Role of Reduced Air Density Along the Lightning Leader Path to Ground in Increasing X-Ray Production Relative to Normal Atmospheric Conditions[J]. GEOPHYSICAL RESEARCH LETTERS,2019,46(15):9252-9260. |
APA | Tran, M. D.,Kereszy, I,Rakov, V. A.,&Dwyer, J. R..(2019).On the Role of Reduced Air Density Along the Lightning Leader Path to Ground in Increasing X-Ray Production Relative to Normal Atmospheric Conditions.GEOPHYSICAL RESEARCH LETTERS,46(15),9252-9260. |
MLA | Tran, M. D.,et al."On the Role of Reduced Air Density Along the Lightning Leader Path to Ground in Increasing X-Ray Production Relative to Normal Atmospheric Conditions".GEOPHYSICAL RESEARCH LETTERS 46.15(2019):9252-9260. |
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