Theory and Simulation of the Formation and Evolution of Meteor Plasmas

流星等离子体形成演化理论与模拟

• 批准号: 1244842
• 负责人: Yakov Dimant
• 金额: $ 30万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-12-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1244842&HistoricalAwards=false
• 关键词: Theory; Simulation; Formation; Evolution; Meteor

This project addresses the topic of meteorite effects on the upper atmosphere by using physics-based models and interpreting data collected at NSF radar facilities. Particles that impact the Earth's upper atmosphere with sufficient energy create high-density plasmas in the E-region ionosphere, seeding the upper atmosphere with an array of metal ions and atoms. A better understanding of meteor plasma dynamics and its radiowave scattering characteristics is needed in order to be able to utilize the information that radars generate about meteors. The project will address the following questions: (1) How do meteor plasmas evolve from their initial ablation and ionization through the early-stage kinetic expansion to their later-stage diffusion and turbulence? (2) What characteristics of the meteor plasma influence radar head echoes? (3) Can more accurate theoretical and computational models improve our quantitative understanding of radiowave scattering? (4) How do large-scale atmospheric inhomogeneities and neutral wind shears modify the evolution of the long-lived plasma trail produced by the meteoroid? Answering these questions will lead to progress in understanding the physics of the highly collisional lower ionosphere and will provide better interpretations of measurements made by radar.Beyond contributions to Aeronomy, the results of this work will be useful to space science and engineering, and provide a better understanding of potential hazards due to particles. The simulator development could be broadly applicable to plasma physics problems. The project will support a full-time graduate student and an undergraduate. The PI and CoPI will share their knowledge and enthusiasm about space and meteor science with the larger community through outreach to K-12 schools and at the University.

该项目通过使用物理模型和解释国家科学基金会雷达设施收集的数据，探讨陨石对高层大气的影响。以足够能量撞击地球高层大气的粒子在E区电离层中产生高密度等离子体，用金属离子和原子阵列播种高层大气。需要更好地了解流星等离子体动力学及其无线电波散射特性，以便能够利用雷达产生的关于流星的信息。该项目将解决以下问题：（1）流星等离子体如何从最初的烧蚀和电离经过早期的动力学膨胀到后期的扩散和湍流？(2)流星等离子体的哪些特性会影响雷达头的回波？(3)更精确的理论和计算模型能提高我们对无线电波散射的定量理解吗？(4)大尺度大气不均匀性和中性风切变如何改变流星体产生的长寿命等离子体尾迹的演化？对这些问题的研究将促进对高度碰撞的低电离层物理的理解，并将更好地解释雷达测量结果。除了对高层大气物理学的贡献外，这项工作的结果将对空间科学和工程有用，并更好地了解粒子的潜在危害。该模拟器的开发可广泛应用于等离子体物理问题。该项目将支持一名全日制研究生和一名本科生。PI和CoPI将通过与K-12学校和大学的外联活动，与更大的社区分享他们对空间和流星科学的知识和热情。