Ionization of air by corona discharge

The objective of this project is to create low density plasma by generating corona discharge by applying a high dc potential in a test section, consisting of a steel tube with a wedge shaped electrode. Once ionization has been initiated, a probe is introduced into the plasma to detect plasma characteristics at various axial distances away from the test section. This is to measure how far away from the electrodes the plasma persists in the air. A high voltage dc power supply has been designed and assembled specifically for this project. This study is a precursor to an upcoming research study to ionize supersonic air in a shock tunnel by the same corona discharge method. Therefore the test section built for this study is designed to fit onto a shock tunnel. The high voltage dc power supply is also designed to be applied to the supersonic corona discharge study. This study will help in the design of diagnostic probes and apparatus for the analysis of plasma created within the supersonic flow in the upcoming project. Results from this study show that corona discharge is taking place and it has been verified visually and by measurements of voltage and current and ions emanating into the ambient air from the test section have been detected. These results show that the test section, the power supply and other apparatus developed can be applied to the supersonic corona discharge study.