  A pulsed oscillating power amplifier has been developed to apply high
frequency biasing voltage to an electrode at the edge of the STOR-M tokamak
plasma. The power amplifier can deliver a peak-to-peak oscillating voltage up
to 120V and current 30A within the frequency range of 1kHz-50kHz. The electrode
is located in the equatorial plane at radius $\rho = 0.88$. The frequency of
the applied voltage has been varied between discharges. It is observed that the
plasma density and soft x-ray intensity from the plasma core region usually
increase at lower frequency regime 1kHz-5kHz as well as relatively higher
frequency regime 20kHz-25kHz but seldom increase in between them. Increment of
$\tau_{p}$ \& $\tau_{E}$ have been observed from the derivations of
experimental data in both frequency regimes. Transport simulation has been
carried out using the ASTRA simulation code for STOR-M tokamak parameters to
understand the physical process behind experimental observations at higher
frequency branch. The model is based on GAM excitement at resonance frequency
associated with Ware-pinch due to oscillating electric field produced by
biasing voltage which can suppress anomalous transport. Simulation results
reproduce the experiment quite well in terms of the density, particle
confinement as well as energy confinement time evolution. All those results
indicate high frequency biasing is capable of improving confinement
efficiently.
