Detailed properties of RF plasmas sustained by an RF external source o
f 13.56 MHz, and 270 V are presented using self-consistent Monte Carlo
simulations in an Ar-like model gas. It is shown that most of the RF
external electric field is absorbed in the sheath regions and ions can
not follow the RF field. The time-dependent distribution of the number
of excitation collisions is shown to give a physical picture of the m
oving sheath boundary which oscillates with the RF electric held. It i
s shown that a lower gas pressure yields a distribution with a wider s
heath region which gives dominantly the capacitive component of impeda
nce. A trial investigation of the similarity rule for the bulk region
of RF plasmas is presented with respect to the electric field, the ele
ctron density, the conduction current density, and the mean electron v
elocity in the direction of the current.