Collaborative Research: Energetic Particle Precipitation Mechanisms in the Inner Magnetosphere: Van Allen Probes and Incoherent Scatter Radar Coordinated Measurements

合作研究：内磁层中的高能粒子沉淀机制：范艾伦探头和非相干散射雷达协调测量

• 批准号: 1732359
• 负责人: Robert Marshall
• 金额: $ 12.08万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1732359&HistoricalAwards=false
• 关键词: Collaborative; Research; Energetic; Particle; Precipitation

This project will examine the mechanisms by which charged particles in Earth's magnetic field travel both out of and through the atmosphere. Identifying these mechanisms is important for understanding how the various layers of the near-Earth environment are coupled. Understanding the neutral and charged atmosphere has become of increasing interest for understanding the background in which space weather events play. Data from NSF supported facilities such as the Advanced Modular Incoherent Scatter Radar (AMISR) will be analyzed in conjunction with space craft data. This award will also fund two postdoctoral researchers.Current particle precipitation theories assume that energetic particles in the magnetosphere precipitate into the atmosphere after undergoing pitch-angle scattering into the loss cone due to interactions with waves at or near the geomagnetic equator. However, the experimental verification of the effect of the multiple candidate waves on the particles' pitch-angle distributions has not been definitively established. This project brings together height-resolved measurements of ionization in the ionosphere, in situ measurements of pitch-angle scattering in the inner magnetosphere, and multidisciplinary expertise to achieve closure for all wave modes that may be involved in electron precipitation mechanisms. Instances of temporally coincident Van Allen Probes' measurements of particles and waves in the radiation belt (or ring current) and Poker Flat Incoherent Scatter Radar (PFISR) measurements of particles precipitating into the ionosphere near the foot-point of the Van Allen Probes' flux tubes will be identified. The loss-cone distribution functions created by candidate waves for pitch-angle scattering using the quasi-linear diffusion equations will be calculated. Changes in the phase-space distribution of electrons that are produced by the electric and magnetic wave fields in the frequency range from a few Hz to several kHz will be quantified by applying UCLAs Full Diffusion Code to Van Allen Probes' particle and field measurements. Finally, a comparison of the ionization profiles produced in the atmosphere by loss cone distributions calculated from Van Allen Probes' data with the ionization profiles directly measured with PFISR.

该项目将研究地球磁场中的带电粒子离开和穿过大气层的机制。识别这些机制对于理解近地环境的各个层如何耦合非常重要。了解中性和带电大气对于了解太空天气事件发生的背景越来越感兴趣。来自 NSF 支持的设施（例如高级模块化非相干散射雷达（AMISR））的数据将与航天器数据结合进行分析。该奖项还将资助两名博士后研究人员。当前的粒子沉淀理论假设，由于与地磁赤道处或附近的波相互作用，磁层中的高能粒子在经历俯仰角散射到损失锥中后沉淀到大气中。然而，多个候选波对粒子俯仰角分布影响的实验验证尚未明确建立。该项目汇集了电离层电离的高度分辨测量、内磁层中俯仰角散射的原位测量以及多学科专业知识，以实现可能涉及电子沉淀机制的所有波模式的闭合。范艾伦探测器对辐射带（或环流）中的粒子和波的测量以及扑克平非相干散射雷达 (PFISR) 对范艾伦探测器通量足点附近沉淀到电离层中的粒子的测量在时间上重合的实例管将被识别。将使用准线性扩散方程计算由用于俯仰角散射的候选波创建的损失锥分布函数。通过将加州大学洛杉矶分校的完整扩散代码应用于范艾伦探测器的粒子和场测量，可以量化频率范围从几赫兹到几赫兹的电波场和磁波场产生的电子相空间分布的变化。最后，将根据 Van Allen 探针数据计算出的损耗锥分布在大气中产生的电离剖面与使用 PFISR 直接测量的电离剖面进行比较。

项目成果

Solving the auroral-arc-generator question by using an electron beam to unambiguously connect critical magnetospheric measurements to auroral images

• DOI: 10.1016/j.jastp.2020.105310
• 发表时间: 2020-09
• 期刊: Journal of Atmospheric and Solar-Terrestrial Physics
• 影响因子: 1.9
• 作者: J. Borovsky;G. Delzanno;E. Dors;M. Thomsen;E. Sanchez;M. Henderson;R. Marshall;B. Gilchrist;G. Miars;B. Carlsten;S. Storms;M. Holloway;D. Nguyen

A Generalized Method for Calculating Atmospheric Ionization by Energetic Electron Precipitation

高能电子沉淀计算大气电离的通用方法

• DOI: 10.1029/2020ja028482
• 发表时间: 2020
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Xu, Wei;Marshall, Robert A.;Tyssøy, Hilde Nesse;Fang, Xiaohua
• 通讯作者: Fang, Xiaohua

A Method for Calculating Atmospheric Radiation Produced by Relativistic Electron Precipitation

相对论性电子沉淀大气辐射的计算方法

• DOI: 10.1029/2021sw002735
• 发表时间: 2021
• 期刊: Space Weather
• 影响因子: 3.7
• 作者: Xu, Wei;Marshall, Robert A.;Tobiska, W. Kent
• 通讯作者: Tobiska, W. Kent

Pitch Angle Dependence of Energetic Electron Precipitation: Energy Deposition, Backscatter, and the Bounce Loss Cone

高能电子沉淀的俯仰角依​​赖性：能量沉积、反向散射和弹跳损失锥

• DOI: 10.1002/2017ja024873
• 发表时间: 2018
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Marshall, R. A.;Bortnik, J.
• 通讯作者: Bortnik, J.

Characteristics of Energetic Electron Precipitation Estimated from Simulated Bremsstrahlung X‐ray Distributions

根据模拟轫致辐射 X 射线分布估算的高能电子沉淀特征

• DOI: 10.1029/2018ja026273
• 发表时间: 2019
• 期刊: Journal of Geophysical Research: Space Physics
• 作者: Xu, Wei;Marshall, Robert A.
• 通讯作者: Marshall, Robert A.