Modulation of the plasma current has been used successfully to suppress MHD activity. This was achieved in discharges near the density limit where large MHD m = 2 tearing modes were suppressed by sufficiently large plasma current oscillations. The modulation of the plasma current must be large enough to move the resonance q = 2 surface outside the island width on a timescale faster than the growth time of the instability. These observations resemble those predicted in a previous study of non-linear effects on the m = 1 mode.

Since the physical and electrical properties of plasmas are similar to the semiconductor
device, the plasma devices are proposed to be good candidates for switching controlled
devices while applied in harsh environments. In the proposed paper, a microplasma device
with dielectric barrier structure constructed with three electrodes (two driven electrodes and
one trigger electrode) is fabricated, and the electrical characteristics of the proposed device
are investigated in 2 kPa of argon. From the experimental results, a stable conducting current
is obtained through two driven electrodes in the device due to gas discharge, since the
hysteresis characteristic of discharge plasmas (discharge is still maintained when driven
voltage is below the breakdown voltage of the gas because of the existence of residual charge
particles), the device can be switched from OFF to ON state through pre-discharge by a pulse
applied on the trigger electrode. While in the device ON, this trigger voltage attracts channel
charged particles to the surface of the dielectric layer, quenching the discharge plasma current
and the device can be switched from ON to OFF state. The trigger pulse that makes the
device switch successfully is from single to continuous up to 80 kHz. The influence of pulse
parameters on the switching process is also investigated, pulse amplitude and pulse width are
found to be important to whether the device can be switched ON or OFF, peak current after
switched, and the response speed of switching ON current, however, these switching
parameters are barely affected by the rising and falling time of the pulse. The results are
significant for the application of microplasma switching devices.