| 项目编号: | 1723588
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| 项目名称: | Quantifying Energetic Electron Precipitation Driven By Magnetospheric Waves |
| 作者: | Wen Li
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| 承担单位: | Trustees of Boston University
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| 批准年: | 2017
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| 开始日期: | 2017-01-01
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| 结束日期: | 2020-04-30
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| 资助金额: | 282943
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| 资助来源: | US-NSF
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| 项目类别: | Continuing grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Geosciences - Atmospheric and Geospace Sciences
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| 英文关键词: | wave
; plasma wave
; electron precipitation
; result
; wave intensity
; wave-driven electron pitch angle scattering loss
; electron radiation belt
; radial distance
; radiation belt electron dynamics
; particular wave-particle interaction
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| 英文摘要: | Waves exist in space plasmas just as in the oceans and the atmosphere. In these plasmas, collisions between charged particles are rare. As a result, plasma waves are a major means of transferring energy from one charged particle population to another. Charged particles "surf" the waves. To first order, those that are moving slightly faster than the waves are energized, while those moving slower lose energy to the waves causing them to grow. There are a wide variety of plasma waves with different properties and different source mechanisms. Three of these (plasmaspheric hiss, chorus, and electromagnetic ion cyclotron (EMIC) waves) are widely believed to play significant roles in the depletion of the electron radiation belts but how this happens and how each contributes with local time and radial distance are still-open and strongly debated questions of fundamental importance. During their interactions with the waves, electrons are scattered out of their trapped orbits and sent on trajectories into the dense atmosphere where they are lost through collisions. The work will independently examine experimental observations and, most importantly, use theoretical tools to understand the interactions leading to the precipitation. The science questions to be addressed in this proposal are particularly important, since electron precipitation leads to chemical changes in the upper atmosphere, and is critical in regulating ring current and radiation belt electron dynamics. The grant will support the further training and development of a promising female early-career scientist. The results will be useful to the broader space physics and upper atmosphere communities, to researchers studying the chemistry of the middle atmosphere, and for space environment applications, such as active mitigation techniques for both natural and artificial radiation in space.
Testing theoretical ideas about particular wave-particle interactions and the variations in the space environment that effect them has been difficult because the waves are measured at large radial distances in the magnetosphere while the electron precipitation that they produce must be viewed from low-earth orbit. To complicate matters, the mix of plasma waves depends on the radial distance and magnetic local time but in addition is an as yet to be determined function of the severity of space weather storming, and the phase of the storm. The principal investigator (PI) has developed an innovative technique to analyze the physical relationship between wave intensity and wave-driven electron pitch angle scattering loss, which can be directly implemented using conjugate observations from near-equatorial and low-altitude satellites. This project, which uses both theory and observation, will provide a definitive understanding of the quantitative contribution of each type of plasma wave to electron precipitation within various energy ranges and in different L-MLT regions. The results will provide a highly important contribution to our wider understanding of the mechanisms that regulate the hazardous radiation environment surrounding the Earth. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/90707
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| Appears in Collections: | 全球变化的国际研究计划
科学计划与规划
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| Recommended Citation: | |
Wen Li. Quantifying Energetic Electron Precipitation Driven By Magnetospheric Waves. 2017-01-01.
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