CAREER: Kinetic Theory of Irreversible Processes

University Of Texas At Austin, Austin TX

Investigators

Abstract

This award is funded in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This CAREER award supports bringing together theory, numerical simulations and spacecraft data analysis to advance our understanding of fundamental plasma processes. Plasmas are gases made of electrically charged particles, and they can be found everywhere in our universe. Neon lights, lightning, auroras, stars and the interplanetary space are all examples of matter in the plasma state. Electromagnetic interactions play a crucial role in the dynamics of plasmas, including plasma energization and heating. For example, such interactions are responsible for heating the outer solar atmosphere, the solar corona, to temperatures in excess of one million degrees. The wind of plasma continuously emitted by the sun into the interplanetary space, the solar wind, is also heated to temperatures higher than what current theories predict. One of the open questions in plasma physics is how the energy stored in the electric and magnetic fields can ultimately heat a plasma. This problem will be investigated with the support of this award by developing cutting-edge numerical tools complemented by theory and analysis of data from past and current space missions. The research will be integrated with an enhanced space physics education plan for STEM disciplines at all levels of education. Engaging activities will be organized through summer camps and showcase lessons to enhance student awareness about space physics and its impacts on life and technology. This award establishes a research program that addresses the interplay between kinetic effects and the dynamics on the large scales in turbulent systems such as the natural plasmas of the heliosphere. Most of the plasma environments encountered in nature and in the laboratory may be classified as weakly collisional or collisionless, in the sense that the timescales associated with collisional relaxation are orders of magnitude longer than the typical dynamical ones. As a consequence, plasmas are most often far from thermodynamic equilibrium, and transport models based on weak perturbations from such states do not apply. Instead, kinetic mechanisms such as wave particle interactions play a crucial role in the processes of energy dissipation and plasma energization. The research effort supported with this award aims to understand the two-way feedback between kinetic physics and large-scale dynamics to advance knowledge of the processes that govern the turbulent cascade, dissipation and particle energization in weakly collisional magnetized plasmas. To this end, an extended hybrid collisional kinetic model will be developed and used to investigate, for the first time, turbulence in weakly collisional magnetized plasmas. In-situ spacecraft data analysis from past and current space missions will be analyzed and compared with numerical and theoretical results. Results from this work will find application in heliospheric environments, but also in more exotic astrophysical systems such as stellar and pulsar winds, accretion disks around widely different central objects, and the interstellar medium. 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.