Generation of Microplasma Using Pulsed Discharge of Ethanol Droplet in Air

An ethanol droplet of 300 µm in diameter is used to create a dense microplasma by pulsed discharge. The pulsed discharge took place when the droplet came into the space between miniature electrodes across which a dc high voltage was applied. The vaporization and dissociation of the ethanol droplet were confirmed in the discharge because the atomic line of hydrogen was observed by optical emission spectroscopy. Molecular hydrogen was detected as a product after the discharge of the ethanol droplet. The discharge of a droplet in air and that of a micro bubble in liquid are in opposite configurations, which is a duality in nature. A single microbubble discharge in pure water was conducted. The gas breakdown of air took place in the bubble and bright emission was observed locally at the interface between the bubble and the electrode.