Collaborative Research: Particle Energization in Turbulence and Magnetic Reconnection

Princeton University, Princeton NJ

Investigators

Abstract

This three-year research project aims to provide an essential framework of knowledge about the physical mechanisms of particle energization that will likely be needed to make a definitive determination of the heating mechanism of the solar corona. Furthermore, fundamental insights into the multi-scale problem of particle energization in magnetic reconnection and plasma turbulence -- a major goal of the research project -- will lead to an improved ability to achieve the societal goal of predicting the impacts of extreme space weather events, in particular the acceleration of hazardous solar energetic particles by these mechanisms. Plasma turbulence and magnetic reconnection are two grand challenge problems in heliophysics, and the overlap and interplay of these two incompletely understood mechanisms represents an important frontier for heliophysics research. This three-year research project targets a major unanswered question on this frontier, namely: to what extent does magnetic reconnection play a role in the dissipation of plasma turbulence at small scales? In order to make progress in answering this fundamental question, during this project magnetic reconnection and plasma turbulence simulations will be performed using both the AstroGK and Gkeyll kinetic simulation codes. The project teams will investigate the particle energization using a guiding-center analysis and a pressure tensor calculation, along with a single-point field-particle correlation analysis to determine the characteristic velocity-space signatures of specific energization mechanisms associated with collisionless magnetic reconnection. Finally, these signatures will be sought in the turbulent magnetosheath plasma by analyzing the electromagnetic field and particle velocity distribution function measurements from the Magnetospheric Multiscale (MMS) mission. This three-year project will support the education and Ph.D. thesis research of a graduate student in space plasma physics at the University of Iowa. Furthermore, a refined implementation of the novel field-particle correlation technique to the analysis of particle energization in heliospheric plasmas can be subsequently applied to understand the fundamentals of plasma heating and particle acceleration in space and astrophysical plasmas due to turbulence, reconnection, or collisionless shocks; this is a major goal of the heliophysics community as outlined by the 2013 NRC Heliophysics Decadal survey. The research results obtained during the project will be disseminated broadly through presentations to the scientific community at national and international meetings and publication in the peer-reviewed literature. Elements of this research will be incorporated into public outreach events for school audiences of all ages as well as public lectures on plasma physics, astrophysics, and space physics. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research. 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.