Operation and mode jumps in low-frequency (500 kHz) radio-frequency inductively coupled plasmas are investigated. The discharge is driven by a flat inductive coil which can excite the electrostatic (E) and electromagnetic (H) discharge modes. The power transfer efficiency and mode transition behavior are studied. It is found that the power reflection coefficient as a function of the input power is minimal in the vicinity of the mode transitions and exhibits hysteresis, which is also observed when the operating gas pressure is varied.

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Current-driven dust-acoustic wave instabilities in a collisional plasma with variable-charge dusts are studied. The effects of electron and ion capture by the dust grains, the ion drag force, as well as dissipative mechanisms leading to changes in the particle numbers and momenta, are taken into account. Conditions for the instability are obtained and discussed for both weak and strong ion drag. It is shown that the threshold external electric field driving the current is relatively large in dusty plasmas because of the large dissipation rates induced by the dusts. The current-driven instability may be associated with dust cloud filamentation at the initial stages of void formation in dusty RF discharge experiments.