Collaborative Research: A Simulation and Theoretical Analysis of Meteor Evolution over Scales Ranging from Sub-microseconds to Minutes

每天都有数十亿个极其微小的颗粒，通常重量不到一粒沙子，影响地球的高层大气。 这些粒子在高层大气中播种了一系列金属离子和原子，这些离子和原子对大气的化学性质有重要影响，并在制造尘埃中发挥作用，尘埃反过来又为云播种。 该奖项将进一步发展流星物理学领域，通过建模流星演变，从他们进入大气层的点，通过他们的耗散。 我们将使用雷达观测来测试我们的模型和理解。该研究具有广泛的应用前景。 航天器设计者需要知道粒子轨道和质量的分布，以减少潜在的危险。太阳系科学家利用流星体群的特征来更好地了解外太阳系及其演变。大气科学家利用流星体数据估计沉积在高层大气中的物质数量及其化学演变。更深入地了解流星等离子体物理学将提高更广泛的科学和工程界对流星和高层大气地球科学的知识。 该项目涉及代表性不足的群体的成员，并支持研究生和本科生。 开发的代码将是开源的。该团队将继续努力，通过与媒体，K-12学校和大学的公开讲座，与更大的社区分享他们对空间和流星科学的知识和热情。这将广泛提高STEM教育和人才。 在过去的几十年里，流星研究人员使用模拟，理论和观测来研究流星等离子体动力学及其雷达测量。该奖项将把这项工作扩展到仍然知之甚少的领域：流星消融的早期阶段，流星引起的等离子体波的行为，空间变化的大气和流星之间的相互作用，以及流星等离子体对无线电波的散射。该团队将生成比现有模型更准确和可靠的新模型，然后应用这些基于物理的模型来解释雷达收集的数据。 该奖项将有助于回答以下问题：（1）各种流星体的消融速度有多快？(2)流星等离子体是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？(3)更精确的理论和计算模型能否提高研究人员对无线电波散射的定量理解？(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？解决这些问题将有助于进一步了解75至120公里高度的大气动力学。它将为雷达和光学测量提供更好的解释。这项研究将解决NSF/Aeronomy方案说明中列出的第一个科学目标：“高层大气的动力学和能量学，特别强调80至150公里之间难以观测的区域”。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

Every day billions of extremely small particles, typically weighing less than a grain of sand, impact the Earth’s upper atmosphere. These particles seed the upper atmosphere with an array of metal ions and atoms which have important effects on the chemistry of the atmosphere and play a role in creating dust, which in turn seeds clouds. This award will further develop the field of meteor physics through modeling meteor evolution from their point of entry into the atmosphere through their dissipation. We will use radar observations to test our models and understandings. The research has a wide range of applications. Spacecraft designers need to know the distribution of particle orbits and masses in order to reduce potential hazards. Solar system scientists use meteoroid population characteristics to better understand the outer solar system and its evolution. Atmospheric scientists apply meteoroid data to estimate the amount of material deposited in the upper atmosphere and its chemical evolution. A deeper understanding of meteor plasma physics will improve the broader scientific and engineering community’s knowledge of meteor and upper atmosphere geoscience. This project involves members of underrepresented groups and supports graduate and undergraduate students. The code developed will be open source. The team will continue their efforts to share their knowledge and enthusiasm about space and meteor science with the larger community through outreach to the media, K-12 schools, and at universities through public talks. This will broadly enhance STEM education and talent. Over the past decades, meteor researchers have used simulations, theory, and observations to study meteor plasma dynamics and their radar measurements. This award will extend this work to areas that remain poorly understood: the early stage of meteor ablation, the behavior of meteor-induced plasma waves, the interaction between a spatially variable atmosphere and meteors, and the scattering of radio waves by meteor plasmas. The team will generate new models more accurate and reliable than those that currently exist, and then apply these physics-based models to interpret data collected by radars. This award will help answer the following questions: (1) How rapidly does ablation proceed for various meteoroids? (2) How do meteor plasmas evolve from their initial ablation and ionization through the early-stage kinetic expansion to their later-stage diffusion and turbulence? (3) Can more accurate theoretical and computational models improve researchers’ quantitative understanding of radio wave scattering? (4) How do large-scale atmospheric inhomogeneities and neutral wind shears modify the evolution of long-lived plasma trails produced by meteoroids? Answering these questions will lead to progress in understanding atmospheric dynamics between 75 and 120 km altitude. It will provide better interpretations of measurements made by radar and optics. This research will address the first scientific goal listed on the NSF/Aeronomy Program Description: “Dynamics and energetics of the upper atmosphere, with particular emphasis on the hard-to-observe region between 80 and 150 km.”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.