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

INSPIRE奖的部分资金来自地球科学理事会大气和地球空间科学部的航空和磁层物理项目，以及数学和物理科学理事会的等离子体物理项目。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。这些粒子及其相互作用产生的伽马射线、x射线和无线电辐射，揭示了空间环境的基本物理学。在地球空间中，粒子在磁层中被各种机制加速，能量高达10兆电子伏。至少从20世纪50年代开始，有针对性的空间粒子注入实验已经使太空等离子体的科学研究成为可能。然而，这些受控实验主要基于相对低能的电子束（40 keV）。在磁层和大气层之间注入mev级电子束的受控实验将使几种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；确定高能粒子如何加速、传输和丢失；理解波粒相互作用的起源和影响。这个项目有两个并行的目标：第一个是科学的，另一个是技术的。为了实现科学目标，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，以探索电子束的各种特性。在科学调查中确定的光束特性范围将指导该项目的主要技术目标，即定义线性加速器的规格，其尺寸、功率和形状因素适合于空间部署，并能够产生实现科学封闭所需的光束特性。这项研究解决了太阳物理学年代际调查确定的高优先科学领域，并与美国宇航局的范艾伦探测器任务的科学目标直接相关。这项研究也将有多种实际应用。例如，阐明波粒相互作用如何导致辐射带失去电子进入电离层，将使减轻空间天气影响的技术成为可能。研究相对论电子束与大气之间相互作用的实验将为理解放电和化学反应路径的修改提供大量的诊断可能性，这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.