  Angular momentum transport and particle acceleration during the
magnetorotational instability (MRI) in a collisionless accretion disk are
investigated using three-dimensional particle-in-cell (PIC) simulation. We show
that the kinetic MRI can provide not only high energy particle acceleration but
also enhancement of angular momentum transport. We find that the plasma
pressure anisotropy inside the channel flow with $p_{\|} > p_{\perp}$ induced
by active magnetic reconnection suppresses the onset of subsequent
reconnection, which in turn leads to high magnetic field saturation and
enhancement of Maxwell stress tensor of angular momentum transport. Meanwhile,
during the quiescent stage of reconnection the plasma isotropization progresses
in the channel flow, and the anisotropic plasma with $p_{\perp} > p_{\|}$ due
to the dynamo action of MRI outside the channel flow contributes to rapid
reconnection and strong particle acceleration. This efficient particle
acceleration and enhanced angular momentum transport in a collisionless
accretion disk may explain the origin of high energy particles observed around
massive black holes.

High Energy Astrophysical Phenomena