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.

该提案旨在增进对地球大气层中与闪电活动相关的壮观自然现象的了解，其中一些过程被称为精灵、蓝色和巨大喷流等。这些过程吸引了世界各地一些公民科学家的注意。一种尚未被完全理解的现象被称为地球伽马射线闪光或 TGF，在这些事件中会产生高能量的 X 射线爆发。这项研究的主要目标是发展理论。这项跨学科的工作将揭示 TGF 的来源，它可能与新的 X 射线源的开发相关，并可能对医学成像过程产生影响。其结果是对研究生的培训，并将成为博士论文的一部分。拟议工作的主要动机来自于最近对 TGF 的观察，并探索了导致这些事件的潜在物理过程。核心物理过程是雪崩倍增。的电子被加速在地球物理背景下，该场是由于雷云起电而产生的，或者是由闪电先导产生的，这些电子从电场中获得能量，并在相对论状态下经历电离碰撞的快速倍增。高能光子（X 射线）被空气中的氮和氧原子核散射，这种辐射被称为制动辐射或轫致辐射。最近发现，这些X射线的一部分相对于电子运动而言可以产生种子电子，这会导致原始雪崩的强烈放大。在非常小的空间尺度上发生的影响与现有的观察结果非常吻合。该项目研究了导致观察到的现象的确切物理机制。通过对学生的指导，教育和知识转移将受益于拟议的活动。该奖项是国家科学基金会的法定奖项。使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。