Characterization of Meteoroids and Meteors through Simulations and Remote Sensing Using High-Power Large-Aperture Radars

使用高功率大孔径雷达通过模拟和遥感表征流星体和流星

基本信息

批准号：
2048349
负责人：
Sigrid Elschot
金额：
$ 59.43万
依托单位：
Stanford University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-06-01 至 2024-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2048349&HistoricalAwards=false
关键词：
Characterization Meteoroids Meteors through Simulations

项目摘要

Approximate 100 tons of extraterrestrial matter, primarily composed of meteoroids, enters the Earth’s atmosphere every day. Meteoroids are defined as solid particles of natural origin in space, which typically originate from the breakup of comets and asteroids and are categorized according to their origin. On average, over 100 billion meteoroids enter Earth’s atmosphere daily with masses larger than 1 microgram. Meteoroids travel between 11 and 72.8 km/s relative to the Earth if in solar orbit; a small, though as yet undetermined, fraction originates outside of our solar system, implying that distant stellar systems can impact Earth’s environment. The light and associated physical phenomena associated with a meteoroid’s passage through a planet’s atmosphere is called a meteor, which results from the plasma created by the meteoroid as it ionizes the gas along its trajectory. Although meteoroids have a profound effect on our space environment, we know very little about their fundamental properties. The connection between meteoroid properties and plasma formation still remains poorly understood due to a lack of knowledge regarding how background properties influence the plasma dynamics and also how selection effects in the observing instrument impacts detection. This project seeks to answer these questions by probing into the plasma physics that surrounds the meteoroid, known as the head echo plasma, and uncover the connection between meteoroid properties, plasma formation, and the properties of the background ionosphere. The research will address many of the outstanding questions in the meteor and meteoroid community, including the mass deposition rate into our atmosphere, the dominant density population, and the effect of the background electric and magnetic fields on plasma expansion and distribution. This fundamental research includes the development of three simulations, including a Direct Simulation Monte Carlo (DSMC) model and a Particle-In-Cell (PIC) algorithm to determine the plasma formation and expansion, and a Finite-Difference Time-Domain (FDTD) model to correlate radar signal strength with plasma density. The project team will also collect and analyze High-Power, Large-Aperture (HPLA) radar data at diverse geographic locations. This research will contribute to the National Space Weather Program’s goal of understanding the evolution of ionospheric irregularities, and answer the following three scientific questions:1) What are the properties of meteor plasmas, including peak plasma density and distribution?2) How is meteoroid ablation and plasma formation affected by the physics of the upper atmosphere and ionosphere?3) What are the properties of the parent meteoroids, including mass, bulk density, and velocity, and how do they correlate to the meteor plasmas?The results of this research will enable understanding of impact plasma and facilitate collaboration between MIT Haystack Observatory and Stanford University. The HPLA data, in addition to the models and simulations developed, will be widely disseminated to enhance scientific and technological understanding. Graduate students will be involved in all aspects of the modeling and simulation, and both undergraduate and graduate student students will be able to analyze the HPLA data, which will contribute to the training of the next generation of scientists and engineers. The research will be integrated into the classroom at Stanford University, including three graduate classes and one undergraduate class designed and taught by the PI. In addition to developing and teaching these courses, the PI frequently engages in outreach activities, such as with grade schools, the Mission to Mars Program for undergraduate students, and various television programs, such as National Geographic, the Weather Channel, and PBS NOVA, where she has described how meteoroids can threaten interplanetary space programs. These endeavors will inspire another generation of students beyond those directly engaged at Stanford University to pursue a degree in this field of research.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.

每天大约有 100 吨主要由流星体组成的外星物质进入地球大气层。流星体被定义为太空中自然形成的固体颗粒，通常源自彗星和小行星的分裂，并根据其来源进行分类。平均每天有超过 1000 亿个质量大于 1 微克的流星体在 11 至 72.8 之间移动。公里/秒（如果在太阳轨道上）；一小部分（尽管尚未确定）源自我们的太阳系之外，这意味着遥远的恒星系统可以影响与流星体穿过有关的光和相关物理现象。行星的大气层被称为流星，是流星体沿其轨道电离气体时产生的等离子体的结果。尽管流星体对我们的太空环境有着深远的影响，但我们对它们之间的基本特性知之甚少。由于缺乏关于背景特性如何影响等离子体动力学以及观测仪器中的选择效应如何影响探测的知识，流星体特性和等离子体形成仍然知之甚少。该项目旨在通过探讨等离子体物理学来回答这些问题。该研究将解决流星体和流星体领域的许多悬而未决的问题，包括质量沉积率。进入我们的大气层，占主导地位的人口密度，以及背景电场和磁场对等离子体膨胀和分布的影响这项基础研究包括开发三种模拟，包括直接模拟蒙特卡罗 (DSMC) 模型和确定等离子体的粒子内细胞 (PIC) 算法。该项目团队还将收集和分析不同地理位置的高功率大孔径（HPLA）雷达数据。这项研究将为国家空间天气计划了解电离层不规则演化的目标做出贡献，并回答以下三个科学问题：1）流星等离子体的特性是什么，包括峰值等离子体密度和分布？2）流星体烧蚀和等离子体形成是如何进行的？受到高层大气和电离层物理学的影响？3) 母流星体的特性是什么，包括质量、体积密度和速度，以及它们与流星等离子体有何关系？这项研究的结果将有助于理解冲击等离子体和促进麻省理工学院海斯塔克天文台和斯坦福大学之间的合作，除了开发的模型和模拟之外，还将广泛传播以增强研究生对建模和模拟的各个方面的了解。本科生和研究生将能够分析 HPLA 数据，这将有助于下一代科学家和工程师的培训。该研究将融入斯坦福大学的课堂，包括设计的三个研究生班和一个本科生班。并由 PI 授课。除了开发和教授这些课程之外，PI 还经常参与外展活动，例如与小学、针对本科生的火星任务计划以及各种电视节目，例如国家地理、天气频道和 PBS NOVA、她描述了流星体如何威胁行星际空间计划，这些努力将激励斯坦福大学直接参与的下一代学生攻读该领域的学位。该奖项反映了美国国家科学基金会的法定使命，并被认为值得支持。通过评估使用基金会的智力价值和更广泛的影响审查标准。