Three-Dimensional Numerical Modeling of Sprite Streamers

雪碧流光的三维数值建模

• 批准号: 2247153
• 负责人: Ningyu Liu
• 金额: $ 47.84万
• 依托单位: University of New Hampshire
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2247153&HistoricalAwards=false
• 关键词: Three; Dimensional; Numerical; Modeling; Sprite

This award will investigate the fundamental physics of sprite streamers using a recently developed, high-performance plasma discharge fluid simulation code, in close conjunction with the latest high-speed images of sprites. About thirty years ago, it was discovered that powerful lightning strokes can cause spectacular Transient Luminous Events (TLEs) in the earth’s upper atmosphere. Sprites are one of the TLEs. Subsequent research has found that sprites share similar physical characteristics as those commonly known spark discharges near the ground. They, however, are much larger and last much longer, because they occur in an environment with greatly reduced air density. Sprites can cause significant modifications of the physical and chemical properties of the upper atmosphere, capable of affecting the propagation of certain radio frequency bands for long-range communications. High-resolution images of sprites have revealed that they consist of a large number of plasma filaments known as streamers. It has been recognized that understanding streamer physics holds the key to learning sprite dynamics and effects. This project will utilize an advanced computer simulation tool to study various poorly understood streamer processes. It will greatly advance our understanding of the physics and effects of sprites. The study will advance knowledge of dielectric breakdown and transient plasma discharges and improve lightning forecast and safety. The software developed in this project will be open source. Graduate and undergraduate students will be supported and involved in this research project, thus contributing to STEM workforce development. This project will investigate streamer branching, collisions between streamer heads, collisions between streamer heads and streamer channels, effects of neutral density perturbations on streamer dynamics, and interaction between streamers and the lower ionosphere. Various three-dimensional simulations will be performed using a high-performance plasma discharge fluid code called AMPLIFI (Adaptive Modeling of PLasma Initiation, Filamentation and Interaction), which was recently developed, to understand the physics of these processes, their roles in sprite dynamics, their electrical and optical effects, and their dependence on the ambient environment. This project will also provide critical information for interpreting high-speed images of sprites and understanding the implications. Concrete knowledge of the dependence of sprite streamer dynamics on ambient neutral or electrical conditions will be obtained, and this will enable the development of potentially powerful remote sensing approaches to studying the mesosphere/D region ionosphere by observing sprites. The study of the neutral density perturbation effects on sprite streamer dynamics will also reveal a novel neutral-ion coupling mechanism enabled by a strong electric field.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.

该奖项将与最新的Sprites的最新高速图像密切结合使用，该奖项将使用最近开发的高性能等离子体排放流体模拟代码来研究Sprite流媒体的基本物理。大约30年前，发现强大的闪电中风会在地球上层大气中引起壮观的瞬态发光事件（TLE）。精灵是TLE之一。随后的研究发现，精灵具有与地面附近常见的火花放电相似的物理特征。但是，它们更大，持续时间更长，因为它们发生在空气密度降低的环境中。精灵可以对高层大气的物理和化学特性进行重大修改，能够影响某些射频频带的传播，以进行远程通信。精灵的高分辨率图像表明，它们由大量的血浆丝组成，称为流媒体。人们已经认识到，了解流媒体物理是学习精灵动态和效果的关键。该项目将利用高级计算机仿真工具来研究各种不良理解的流媒体流程。这将大大提高我们对精灵物理和影响的理解。这项研究将提高人们对饮食分解和瞬时血浆排放的了解，并改善闪电预测和安全性。该项目中开发的软件将是开源的。研究生和本科生将得到支持并参与该研究项目，从而有助于STEM劳动力发展。该项目将研究流媒体分支，流媒体头之间的碰撞，流媒体头和流媒体通道之间的碰撞，中性密度扰动对流媒体动力学的影响以及彩流器与下电离层之间的相互作用。将使用高性能等离子体排放液代码（称为Amplifi）（血浆启动，细丝和相互作用的自适应建模）进行各种三维模拟，该代码是最近开发的，以了解这些过程的物理，它们在Sprite动力学中的作用，其电气和光学效应及其对环境环境的依赖性。该项目还将提供关键信息，以解释精灵的高速图像并理解含义。将获得有关精灵流媒体动力学对环境中性或电气条件的依赖性的具体知识，这将使潜在强大的远程灵敏度方法能够通过观察Sprites来开发潜在的强大遥感方法来研究中层/D区域电离层。对Sprite流媒体动力学的中性密度扰动效应的研究还将揭示出一种新型的中性离子离子耦合机制，该耦合机制由强烈的电场实现。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来评估的。