Atmospheric pressure plasma jet on floating electrode in air using half bridge resonant converter

In this paper, A continuous glow discharge is investigated which takes place between the two electrodes out of which one is floating in air. The powered electrode geometry is a disk while the floating electrode is a graphite rod with a sharp tip. The voltage of around 5kV and 20 kHz was applied to the powered electrode. This was generated using a half bridge resonant converter operated in above resonant mode. It was observed that the plasma jet was formed when the floating electrode was brought closure to the powered electrode with a gap of 2 - 4 mm. The rms value of the discharge current was 50 uA. It was also observed that this plasma jet discharge very much depends on the geometry of the electrodes. The sharp edge floating electrode helps is generating electric filed suitable for glow discharge. The sufficient secondary emission from a disk shape powered electrode helps in ionization of the medium between the powered and floating electrodes. The reversal of the terminals by making the sharp edge electrode as powered electrode and disk as a floating electrode did not show any discharge. In this configuration the charge accumulation on the disk could not become possible and hence, there could not be any electric field generated to initiate the plasma jet. The other terminal of the electrical supply was completely isolated from the ground in both the cases.