Relativistic Asymmetric Magnetic Reconnection: Theory and Kinetic Modeling

University Of Hawaii, Honolulu

Investigators

Abstract

This project will explore the process of magnetic reconnection in magnetized astrophysical plasmas. Most space and astrophysical systems, including the sun and stars in and out of the milky way, are made up of hot, ionized gas -- a plasma permeated by magnetic fields. Frequently, high energy light and particles are rapidly generated by these systems through a process known as magnetic reconnection. An improved understanding of magnetic reconnection and the radiation it generates will be developed by this project using computer simulations and by including more realistic conditions motivated by astrophysical observations. The simulations will be used to connect the conditions of the plasma to the characteristics of the radiation. The research effort will improve our understanding of how astrophysical plasmas behave and what are the sources of high energy radiation from our galaxy and beyond. This project is jointly funded by the Division of Physics, the Division of Astronomical Sciences, and the Established Program to Stimulate Competitive Research (EPSCoR). The fundamental plasma process of magnetic reconnection will be studied in the relativistic and asymmetric limit, in regimes where the magnetic energy per particle is larger than the rest mass energy and the plasma properties of the interacting magnetic structures differ from each other. The project will attempt to achieve three key goals: (1) develop scaling predictions for relativistic, asymmetric magnetic reconnection; (2) identify relationships between the initial asymmetric plasma parameters and the energetic, non-thermal particle distributions generated by reconnection; and (3) explore the contribution of magnetic reconnection to the non-thermal particle distribution in a global astrophysical system. The first two goals will be approached by performing a survey of plasma simulations of magnetic reconnection, which will be analyzed and compared with derived theoretical predictions. The third goal will be achieved by examining relativistic jet simulations of active galactic nuclei to estimate the reconnection-generated non-thermal spectrum of energetic particles. The parameter regimes to be explored, along with the application to relativistic jets is directly relevant to the growing field of plasma astrophysics and can provide insight into the origin of accelerated high energy particles and the associated impulsive emission in astrophysics. 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.