Excitation of ionization instability in microwave discharge plasma

Summary form only given. In a gaseous discharge, the ionization frequency is a strong function of RF wave field amplitude. A perturbation in the wave distribution can result in strong modification of local ionization rate, and introduce a density perturbation. The modification of the local dielectric constant of the plasma due to the density perturbation leads to effects on wave distribution. The nonlinear self-focusing effect tends to trap wave intensity in the density trough. However, the wave electric field tends to increase with the decrease of the dielectric constant. Therefore, before the self-focusing effect takes over, the induced density perturbation gives rise to a positive feedback to the wave electric field perturbation. An ionization instability can thus be excited. This instability process has been examined analytically by Gil´denburg and Kim (1978), who derived the growth rate and the oscillation frequency of the instability. An experiment was performed to verify the theoretical results