Time-averaged electric potential profiles in a capacitive-coupling parallel-plate electrode neon gas RF discharge plasma

Time-averaged electric potential profiles in a capacitive-coupling parallel-plate electrode neon gas RF discharge plasma have been investigated experimentally. The experiment was conducted by using 65 mm ID, 45 mm long cylindrical discharge tubes with parallel plate electrodes located outside of the discharge vessel and resting against its cylindrical sides. The time-averaged electric field, plasma density and electron temperature were measured by radially movable electrostatic probes placed in the centre of the electrode. The results show that: (i) the electrical potential profiles of the discharge tubes were observed to be significantly influenced by the RF powers and gas pressures; (ii) an asymmetric potential profile was observed, together with a potential barrier in the central region of the discharge tube; (iii) a large quasi-neutral plasma region was not observed in the current experimental conditions; however, a relatively uniform electric field region was observed for gas pressure p<1 Torr; and (iv) the electron temperature decreased with increasing RF powers and gas pressures.