INSPIRE Track 1: Concept Development for Active Magnetospheric, Radiation Belt, and Ionospheric Experiments using In-situ Relativistic Electron Beam Injection

该INSPIRE奖的部分资金来自地球科学局大气和地球空间科学司的大气和磁层物理计划以及数学和物理科学局的等离子体物理计划。研究人员将研究在太空中使用百万电子伏特(MeV)电子束进行受控实验的可行性。高能粒子是地球空间环境的基础。这些粒子及其产生伽马射线、X射线和射电辐射的相互作用，揭示了空间环境的基本物理学。在地球空间中，粒子通过磁层中的各种机制加速，能量超过10 MeV。至少自1950年代以来，有针对性的空间粒子注入实验使对空间等离子体的科学研究成为可能。然而，这些对照实验主要是基于相对较低的能量电子束(40keV)。在磁层和大气层之间注入MeV级电子束的受控实验将使几类重要的科学研究成为可能。其中包括大气-电离层-磁层耦合和大气对长期地磁强迫的响应；确定高能粒子是如何加速、运输和损失的；以及了解波-粒子相互作用的起源和影响。这个项目同时有两个目标：第一个是科学的，另一个是技术的。要达到科学目标，将需要对电子束引起的不稳定性、膨胀和碰撞进行详细的模拟、建模和理论计算，以探索电子束的性质范围。科学调查中确定的束流特性范围将指导该项目的主要技术目标，即确定直线加速器的规格，其尺寸、功率和形状系数可用于空间部署，并能够产生实现科学闭合所需的束流特性。这项研究涉及太阳物理学十年调查确定的高度优先的科学领域，并与美国国家航空航天局的与恒星共处的范艾伦探测器任务的科学目标直接相关。这项研究还将具有多个实际应用。例如，阐明波-粒子相互作用如何导致辐射带将电子损失到电离层，将使缓解空间天气影响的技术成为可能。研究相对论电子束与大气相互作用的实验将为理解放电和修改化学反应路径提供许多诊断可能性，这些路径将使技术能够改变大气中的一氧化氮(NO)和臭氧含量。

This INSPIRE award is partially funded by the Aeronomy and Magnetospheric Physics Programs in the Division of Atmospheric and Geospace Sciences in the Directorate for Geoscience, and the Plasma Physics Program in the Directorate for Mathematical and Physical Sciences. The investigators will study the feasibility of conducting controlled experiments in space using million-electron-volt (MeV) beams of electrons. Energetic particles are fundamental to the geospace environment. These particles, and their interactions that produce gamma rays, x-rays, and radio emissions, shed light on the fundamental physics of the space environment. In geospace, particles are accelerated by various mechanisms in the magnetosphere, with energies upwards of 10 MeV. Targeted space-based particle injection experiments have enabled scientific investigations of space plasmas since at least the 1950s. However, these controlled experiments were mainly based on relatively low-energy electron beams (40 keV). Controlled experiments with MeV-class electron beams injected between the magnetosphere and the atmosphere will enable several types of important scientific studies. These include atmospheric-ionospheric-magnetospheric coupling and the response of the atmosphere to long-term geomagnetic forcing; establishing how energetic particles are accelerated, transported, and lost; and understanding the origin and effects of wave-particle interactions. This project has two concurrent objectives: the first is scientific, the other technological. Meeting the scientific objectives will require detailed simulations, modeling, and theoretical calculations of beam-induced instabilities, expansion, and collisions to explore the range of properties of the electron beams. The range of beam properties identified in the science investigation will guide the principal technological objective of this project, which is to define the specifications of the linear accelerators with size, power, and form factors amenable to space deployment and capable of generating the beam characteristics needed to achieve science closure. This study addresses high priority science areas identified by the Heliophysics Decadal Survey and has direct relevance to the science objectives of NASA's Living With a Star, Van Allen Probes mission. The research will also have multiple practical applications. For instance, elucidating how wave-particle interactions cause the radiation belts to lose electrons into the ionosphere will enable technologies for the mitigation of space weather effects. Experiments investigating interactions between relativistic electron beams and the atmosphere will provide a host of diagnostic possibilities for understanding discharges and the modification of chemical reaction paths that will enable technologies to modify nitric oxide (NO) and ozone content in the atmosphere.