GEM: Transit-time Scattering of Energetic Electrons

GEM：高能电子的渡越时间散射

• 批准号: 1103064
• 负责人: Jacob Bortnik
• 金额: $ 28.5万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1103064&HistoricalAwards=false
• 关键词: GEM; Transit; time; Scattering; Energetic

The Earth's radiation belts consist of a population of energetic electrons that is trapped by the Earth's nominally dipole magnetic field. A major challenge in radiation belt physics is identifying and describing the various processes that contribute to the energization of the electrons, and their loss, particularly uner highly dynamic geomagnetic conditions. The aim of this 3-year project is to quantitatively understand a newly discovered wave-scattering mechanism, termed transit-time diffusion, which has the potential to play an important role in radiation belt energization. This involves scattering by fast magnetosonic waves, which is a class of waves that has not previously been considered important for this problem. A combination of modeling and analytical approaches will be used to answer a number of fundamental questions about this new mechanism and its relative importance for radiation belt dynamics compared to other wave processes.The project will be led and carried out mainly by a team of three early-career scientist and a graduate student will also be trained as part of the project. Energetic electron fluxes in the radiation belts constitute an important space weather concern, as they are known to adversely affect space-based assets upon which modern society is increasingly dependent. Consequently, better understanding and prediction of radiation belt dynamics would be of benefit to society at large.

地球的辐射带由一群高能电子组成，这些电子被地球名义上的偶极磁场所捕获。辐射带物理学的一个主要挑战是确定和描述导致电子充能及其损失的各种过程，特别是在高动态地磁条件下。这个为期3年的项目的目的是定量地了解一种新发现的波散射机制，称为透射时间扩散，它有可能在辐射带通电中发挥重要作用。这涉及到快速磁声波的散射，这是一种以前没有被认为对这个问题很重要的波。建模和分析方法的结合将用于回答有关这种新机制的一些基本问题，以及与其他波过程相比，它对辐射带动力学的相对重要性。该项目将主要由三名早期职业科学家和一名研究生组成的团队领导和实施，作为项目的一部分，他们也将接受培训。辐射带中的高能电子通量是一个重要的空间天气问题，因为众所周知，它们会对现代社会日益依赖的天基资产产生不利影响。因此，更好地了解和预测辐射带的动态将有益于整个社会。