PIC Simulations of the Dayside Magnetopause: Origins and Evolution of
the Electron and Ion Populations in its Boundary Layers
Recent observations and simulations have revealed a wide variety of
plasma processes and multiscale structures at the dayside magnetopause.
In this presentation, we focus on the origins and evolution of the
plasma populations observed in the magnetopause boundary layers. We
present the results of Particle-In-Cell (PIC) simulations encompassing
large volumes of the dayside magnetosphere. The implicit PIC code used
in the study was initialized from a global MHD state of the
magnetosphere for southward interplanetary field conditions.
Three-dimensional plots of the perpendicular slippage indicates that
reconnection occurs over most of the dayside magnetopause. However, the
simulation reveals that the reconnection region has a much more
filamentary structure than the X-line expected from the extrapolation of
2D models and that multiscale structures thread the reconnection
outflow. In particular, the simulation indicates the formation of
multiple layers of electrons with significant field-aligned velocities
within the main magnetopause current layer. We use velocity distribution
functions at different locations in the reconnection outflow to
characterize the origins and evolution of the electron and ion
populations of the magnetosheath and magnetospheric boundary layers.