Abstract
We investigate the onset of magnetic reconnection, utilizing a fully
kinetic Particle-In-Cell (PIC) simulation. Characteristic features of
the electron phase-space distributions immediately before reconnection
onset are identified. These include signatures of pressure non-gyrotropy
in the velocity distributions, and lemon shaped distributions in the
in-plane velocity directions. Further, we explain how these features
form through particle energization by the out-of-plane electric field.
Identification of these features in the distributions can aid in
analysis of data where clear signatures of ongoing reconnection are not
yet present.