Abstract
The vicinity of the electron diffusion region (EDR) at the core of
magnetic reconnection is frequently characterized by agyrotropic
electron velocity distributions such as perpendicular velocity-space
crescents [J. L. Burch et al., Science, DOI:10.1126/science.aaf2939
(2016)]. Although the evolving EDR is not itself an equilibrium state,
its evolution may be slow on electron-cyclotron time scales. When this
is the case, homogeneous equilibrium models are limited in their ability
to model dynamical processes, such as instabilities and wave generation,
in the presence of agyrotropic populations. In order to better study
these processes, we initiate implicit PIC simulations with inhomogeneous
kinetic equilibria built upon agyrotropic electron velocity
distributions measured by the FPI spectrometers on MMS. The methodology
involves the following elements: 1. Modeling the observed agyrotropic
(e.g., crescent) and background plasma distributions 2. Numerically
evaluating self-consistent inhomogeneous equilibria – including
anisotropy 3. Initializing 1D, 2D, and 3D PIC simulations with the
equilibria 4. Evaluating the simulation output for instabilities and the
persistence of the crescents Particle tracing and other visualization
tools will be employed to illustrate the underlying dynamics of
particles and fields – and their interactions.