Computational modelling of a 1-D pulsed argon capacitively coupled plasma discharge to identify heating mechanisms*

This abstract reports on heating mechanisms involved in 1-D pulsed capacitively coupled plasma simulations (CCPs) with argon as the working gas. The bottom electrode is grounded while the top electrode voltage is adjusted by a power controller to provide a power curve that ramps up until a stipulated value and then plateaus till the pulse is switched off. The results of the Ar_4p number density profile indicate the existence of an additional heating mechanism depending on the pulsing frequency. a heating mode is the prevalent mechanism observed during sheath expansion however, sufficiently long afterglow phase introduces a drift-ambipolar (DA) heating mode during early reignition due to electric field induced heating on the sheath edge. The DA heating mechanism is observed primarily in electronegative plasmas, but it is also observed in the electropositive argon plasma albeit to a weaker extent. A pulse frequency of 10 kHz only shows the a heating mode as compared to 0.1 kHz which shows both a and DA mode under sufficiently aggressive input power profile. The DA heating mode is effective only during early re-ignition, accelerating and consequently heating electrons by strong drift and ambipolar electric field at the bulk and sheath edge however, the a mode becomes the sole heating mechanism deeper into the pulse when plasma conductivity recovers to provide effective shielding.