Relativistic Runaway Discharges in the Earth's Atmosphere

地球大气中的相对论失控放电

• 批准号: 2341623
• 负责人: Victor Pasko
• 金额: $ 77.93万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-01 至 2029-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2341623&HistoricalAwards=false
• 关键词: Relativistic; Runaway; Discharges; Earth; Atmosphere

The proposal aims at advancing the knowledge of spectacular naturally occurring phenomena related to lightning activity in the Earth’s atmosphere. Several of such processes are known to the community as sprites, blue and gigantic jets etc. These have attracted the attention of several citizen scientists all over the globe. One such phenomenon, which is still not completely understood is referred to as terrestrial gamma-ray flashes or TGFs. During these events, bursts of X-rays with high energy are generated. The main goal of this research is to develop theoretical work that will shed light on the sources of TGFs. This inter-disciplinary work combines concepts of plasma physics as well as atmospheric processes. It may be relevant to the development of new X-ray sources with possible implications on medical imaging processes. The proposed work will result in the training of a graduate student and will be part of the doctorate thesis. The main motivation for the proposed work results from some recent observations of TGF’s and exploring the underlying physical processes responsible for these events. The core physical process leading is avalanche multiplication of electrons accelerated by force exerted by electric field. In geophysical context the field is generated either as ambient field due to thundercloud electrification or produced by lightning leaders. These electrons gain energy from the electric field and experience quick multiplication in ionizing collisions. In relativistic regime these electrons can radiate energetic photons (X-rays) as they scatter by nuclei of nitrogen and oxygen atoms in air. The radiation is referred to as braking or bremsstrahlung radiation. These X-rays are radiated in all directions and some fraction is radiated backwards with respect to electron motion. These X-rays can produce seed electrons due to photoelectric effect and this leads to strong amplification of the original avalanche. This process is referred to as feedback process. It was discovered recently that these effects occur on very small spatial scales in good agreement with existing observations. This project investigates the exact physical regimes which lead to observed phenomena. The education and transfer of knowledge will benefit from the proposed activity through the mentoring of students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该提议旨在促进与地球大气中闪电活动相关的壮观天然现象的知识。社区将其中的几个过程称为精灵，蓝色和巨大的喷气机等。这些过程吸引了全球几位公民科学家的注意。仍然尚未完全理解的一种现象被称为陆生伽玛射线闪光或TGF。在这些事件中，产生了高能量的X射线爆发。这项研究的主要目的是开发将阐明TGF来源的理论工作。这项跨学科的工作结合了血浆物理学的概念以及大气过程。这可能与开发新的X射线源具有对医学成像过程的影响。拟议的工作将导致培训研究生，并将成为博士学位论文的一部分。拟议工作的主要动机是由于最近对TGF的一些观察结果，并探索了负责这些事件的基本物理过程。核心物理过程领导是通过电场执行的力加速电子产品的雪崩繁殖。在地球物理环境中，由于雷云电气化或雷电领导者产生的，该领域是作为环境场生成的。这些电子设备从电场中获得能量，并在电离碰撞中经历快速乘法。在相对论方面，这些电子设备可以放射性能量照片（X射线）在空气中被核和氧原子散射。辐射称为制动或Bremsstrahlung辐射。这些X射线在所有方向辐射辐射，并且相对于电子运动，一些部分是向后辐射的。这些X射线可以由于光电效应而产生种子电子，这会导致原始雪崩的强大扩增。此过程称为反馈过程。最近发现，这些效果发生在非常小的空间尺度上，与现有观察结果非常吻合。该项目研究了导致观察到现象的确切物理状态。知识的教育和转移将通过学生的心理从拟议的活动中受益。该奖项反映了NSF的法定任务，并通过使用基金会的知识分子优点和更广泛的影响评估标准来评估值得支持。