  This paper demonstrates a dynamical evolution model of the black hole (BH)
horizon. The result indicates that a kinetic area-cells model of the BH's
horizon can model the evolution of BH due to the Hawking radiation, and this
area-cell system can be considered as an interacting geometrical particle
system. Thus the evolution turns into a problem of statistical physics. In the
present work, this problem is treated in the framework of non-equilibrium
statistics. It is proposed that each area-cell possesses the energy like a
microscopic black hole, and has the gravitational interaction with the other
area-cells. We consider both a non-interaction ideal system, and a system with
small nearest-neighbor interactions, and obtain an analytic expression of the
expected value of the horizon area of a dynamical BH. We find that, after a
long enough evolution, a dynamical BH with the Hawking radiation can be in
equilibrium with a finite temperature radiation field. However, we also find
that, the system has a critical point, and when the temperature of the
radiation field surrounding the BH approaches the critical temperature of the
BH, a critical slowing down phenomenon occurs.
