Radio frequency produced high-pressure air constituent plasmas

Summary form only given, as follows. A high-density large volume plasma of air constituent (N/sub 2/, O/sub 2/, Air and Argon mixtures) is created using a high power (1-25 kW) pulsed radio frequency source at high gas pressures. Such high-Pressure air plasmas are finding increasing application in plasma processing industry, as plasma reactors, as light source and as biological decontaminants. One of the major issues particular to such plasma is the high power required to initiate and sustain the discharge. The power requirement to create and sustain the discharge can be reduced by mixing noble gas with air constituents. Initial experiments reveal that noble gas mix of nitrogen, argon and oxygen improves the antenna loading and is beneficial for the break down of air constituents. It also leads to a lower recombination rate. A tangentially injected high-speed swirl gas flow improves the plasma confinement. It also keeps the plasma off the inside walls of the Pyrex chamber and reduces the excessive heating of the plasma chamber. Radio frequency power is coupled through a five turn helical antenna using a capacitive matching network.. A large volume plasma in argon at 20 Torr at moderate radio frequency power 1.5 kW has been produced. Recent results with high power pulsed unit in high-pressure range (100-200 Torr of argon, nitrogen, oxygen and their mixture) will be presented.