  A self-consistent particle-in-cell simulation study is performed to
investigate the effect of driving frequency on the electric field
non-linearity, electron heating mechanism and electron energy distribution
function (EEDF) in a low pressure symmetric capacitively coupled plasma (CCP)
discharge at a constant electron plasma frequency. The driving frequency is
varied from 27.12 MHz to 100 MHz for a discharge gap of 3.2 cm in argon at a
gas pressure of 1 Pa. The simulation results provide insight of higher harmonic
generations in a CCP system for a constant electron response time. The
spatio-temporal evolution and spatial time averaged electron heating is
presented for different driving frequencies. The simulation results predict
that the electric field non-linearity increases with a rise in driving
frequency along with a concurrent increase in higher harmonic contents. In
addition to the electron heating and cooling near to the sheath edge a positive
<J.E> is observed in to the bulk plasma at higher driving frequencies. The EEDF
illustrate enhancement in the population of mid-energy range electrons as
driving frequency increases thereby changing the shape of EEDF from
bi-Maxwellian to nearly Maxwellian. For the constant ion flux on the electrode
surface, a decrease in the ion energy by more than half is observed with an
increase in driving frequency.
