Jason TenBarge, Princeton University

University of Arizona, Theoretical Astrophysics Program (TAP) Colloquia Series
TITLE:
New Perspectives on Diagnosing Electron Energization in Magnetic Reconnection
ABSTRACT:
Magnetic reconnection is a ubiquitous process in space and astrophysical plasmas, and it plays a fundamental role in transforming stored magnetic energy into particle kinetic and thermal energies. Reconnection is thought to produce high energy, non-thermal particles in a variety of systems, including gamma ray bursts, solar and stellar flares, and pulsar magnetospheres. In addition to non-thermal electron production, reconnection also leads to significant thermal energization of both ions and electrons. The thermal heating due to reconnection plays an important role in many systems, including heating the solar corona and accelerating the solar wind, providing electron heating in Earth’s geospace environment, and dissipating energy in the myriad turbulent systems that pervade the universe.
Particle energization in magnetic reconnection has traditionally been examined from a particle, or Lagrangian, perspective using particle-in-cell (PIC) simulations. Guiding-center analyses of PIC particles has suggested that Fermi (curvature drift) acceleration and direct acceleration via the reconnection electric field are the primary electron energization mechanisms. However, both PIC guiding-center analyses and spacecraft observations are performed in an Eulerian frame. We employ the continuum Vlasov-Maxwell solver within the Gkeyll simulation framework to re-examine electron energization in reconnection from a continuum, Eulerian perspective. We separately examine the contribution of each drift energization component to determine the dominant electron energization mechanisms in a moderate guide-field Gkeyll reconnection simulation. We compare the Eulerian (Vlasov Gkeyll) results with the wisdom gained from Lagrangian (PIC) analyses. Time permitting, we will also present the phase-space signature of direct electron acceleration in the large guide magnetic field limit using the field-particle correlation technique.
BIO:
Jason TenBarge is a Research Scholar at Princeton University in the Department of Astrophysical Sciences and at the Princeton Plasma Physics Laboratory. Dr. TenBarge studies basic plasma processes by applying and developing analytical and numerical tools to understand kinetic dissipation and transport processes in space and astrophysical plasmas. He received degrees in Astrophysics and Mathematics from Indiana University in 2003 and a physics Ph.D. in 2009 from the University of Texas at Austin, where his research focused on relativistic plasma astrophysics. From 2009 to 2013, he worked as a postdoctoral research associate at the University of Iowa studying solar wind turbulence. Afterward, he moved to the University of Maryland College Park as a research scientist from 2013 to 2017. In 2017, he joined the astronomy and plasma physics group at Princeton University.