Further investigation of PIA (Persistent Ionization in Air) plasmas using room air

Summary form only given, as follows. Further research on PIA (Brandenburg and Kline 1998) plasmas, glow discharge-type plasmas created in room air, is reported. These plasmas can be made in a modified 1 kW microwave oven (2.45 GHz) and can be sustained for an indefinite period by the microwaves. They have now been made in a much larger size using 915 MHz industrial microwaves at 30-75 kW of microwave power. These new plasmas range from roughly spherical and approximately 50 cm in diameter to highly irregular and dynamic shapes of larger size. Thus it is demonstrated that the PIA phenomenon can be scaled upward in size and power. The properties of the 915 MHz PIA plasmas appear similar to that made with 2.45 GHz, except that visible spectra appear to display more bright bands. The plasma also appears to seek microwave sources, like a classic breakdown, rather than retreat from it, as is the behavior of the PIA at 2.45 GHz. This suggests that the 915 MHz plasmas may be more strongly driven and closer to a classical arc discharge in properties. Further measurements on PIA plasmas will be reported. We believe these plasmas are a new and unusual plasma state first reported by Manwaring and Powell and Finklestein (1970) whom used 30 kW at 75 MHz.