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

Stanford University, Stanford CA

Investigators

Abstract

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.