MULTITUBE SURFACE-WAVE DISCHARGES FOR INCREASED GAS THROUGHPUT AT ATMOSPHERIC-PRESSURE

Large diameter (>10 mm) microwave discharges at atmospheric pressure a re often constricted transversely and, when large gas flow rates are u sed, unstable as far as microwave power coupling is concerned. A group of small bore tubes can be used instead to provide the same gas throu ghput and ensure a higher probability of interaction of molecules to b e processed with the carrier gas. The solution presented provides equa l power sharing in these small diameter plasma columns and it employs preferably a single microwave field applicator, therefore enabling one to use only one power generator and yielding a compact system. This s cheme is based on the properties of surface-wave sustained plasmas and it calls on basic principles of waveguide circuitry. (C) 1998 America n Institute of Physics. [S0021-8979(98)05111-1].