NSF Award
2431533
Meteoroids are small rocky and icy bodies, ranging from dust particles to boulders in size, that are formed from the collision and interaction of asteroids and other larger objects throughout the solar system. Approximately 100,000 kg of extraterrestrial matter, primarily composed of meteoroids, enters the Earth's atmosphere every day. As meteoroids burn up in the atmosphere, they create a plasma, or ionized gas, known as a meteor or a shooting star. The PI plans to study meteors through analysis of meteor observations using radar and developing simulations to capture the physics of the meteoroid shedding material and how that material interacts with the atmosphere. Understanding the physics of the upper atmosphere where meteors are formed is crucial to NSFs mission of progressing science and securing national defense. This research will provide information that can help predict atmospheric effects on spacecraft operations, including potential collisions and failures, reduced satellite lifetime, or communication outages. The development of new simulation techniques has application in many other fields including spacecraft design and analysis, parachute dynamics, and hypersonic reentry vehicles. Involvement of two graduate students is planned in all aspects of the modeling and simulation.<br/><br/>The objective of this proposal is to study the E region through the analysis of high-resolution data from High-Power Large-Aperture (HPLA) radars associated with the smallest, and most numerous, meteoroids. Meteor activity is the primary source of metals in the MLT region and gives origin to the upper atmospheric metallic and ion layers. It is anticipated that the increasing numbers of satellites will lead to a drastic increase in metallic mass deposition in the upper atmosphere as they de-orbit. The mass deposition rate, which depends on impactor properties and background conditions, though critical for modeling the upper atmospheric chemical processes remains poorly understood. The work will lead to the development of a combined Direct Simulation Monte Carlo – Finite Element Method (DSMC-FEM) model, the first of its kind, and modification of an existing Particle-In-Cell (PIC) algorithm to determine plasma formation and expansion. The researchers will then apply a Finite-Difference Time-Domain (FDTD) model to map radar signal strength to plasma density. This research, which will contribute to the National Space Weather Program’s goal of understanding the evolution of ionospheric irregularities, will answer the following scientific questions: (a) How do meteoroids deposit mass within the thermosphere and create localized regions of high-density extraterrestrial material? (b) What kinds of small-scale atmospheric neutral density structures exist at a single geographic location, and can we correlate neutral density to trail echo onset time? And (c) What are the long-term effects of increased material on the MLT region?<br/><br/>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.
