Theory and Simulation of the Formation and Evolution of Meteor Plasmas

该项目通过使用基于物理的模型和解释在美国国家科学基金会雷达设施收集的数据来解决陨石对高层大气影响的主题。粒子以足够的能量撞击地球高层大气，在e区电离层产生高密度等离子体，在高层大气中播种金属离子和原子阵列。为了能够利用雷达产生的有关流星的信息，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。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，通过早期的动力学膨胀演变到后期的扩散和湍流？(2)流星等离子体对雷达头回波有哪些影响？(3)更精确的理论和计算模型能否提高我们对无线电波散射的定量认识？(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轨迹的演变？回答这些问题将有助于理解高度碰撞的低层电离层的物理学，并将对雷达测量结果提供更好的解释。除了对航空学的贡献之外，这项工作的结果将对空间科学和工程有用，并提供对粒子潜在危害的更好理解。该模拟器的开发可以广泛应用于等离子体物理问题。该项目将资助一名全日制研究生和一名本科生。PI和CoPI将通过扩展到K-12学校和大学，与更大的社区分享他们对太空和流星科学的知识和热情。

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.