Design of a modular plasma torch and its interactions with microwaves

The design and construction of the plasma torch module by modifying and reassembling the structural components of two different models of spark plugs are first described. Each module can produce a torch plasma of 1 cm radius and 6 cm height and having a peak density exceeding 1013 cmp3. A set of modules, each connected in series with a ballasting capacitor in the circuit, can be operated as an array sharing a common power source to produce a dense and large volume plasma. The electrical characteristics of the module are studied. It’s shown that the discharge can be maintained, with the aid of a series ballasting capacitor, in a stable diffuse arc. Microwave-plasma interaction is studied in an X-band waveguide by passing the plasma from the torch through pairs of aligned holes on the top and bottom walls of the waveguide. The results show that each torch as a lossy dielectric post, can introduce more than 10 dB attenuation to the propagating microwaves.