Plasma sources are built with two water-cooled coaxial electrodes, a central rod as power electrode and the
outer tube as ground electrode. A ceramic tube has been
placed tightly against the ground electrode to prevent
streamer generations and arcing, forming a structure
similar to the dielectric barrier discharges. Electrode
material has been selected to be surface-anodized aluminum to prevent arc transition. Its relatively high
thermal conductivity as well as electrical conductivity,
lets the plasma source is operable at gas temperatures
by a few hundred degrees lower than the stainless steel
electrode. A gas distributor has been placed to provide
gas flow uniformly as shown in Fig. 1a.