Gas breakdown and plasma generation by dielectric resonator arrays

Dielectric resonators are illuminated by electromagnetic planes waves and used to ignite and sustain arrays of microwave plasmas. The resonators consist of calcium titanate cylinders (nom. 30 mm diam. × 15 mm high). The resonators were arranged in a line with separation distances between 0.5 and 5 mm. We report plasma ignition in the gaps between the resonators using the HEMm resonance1 at 1.1 GHz. Paschen curves of the breakdown field and breakdown voltage are measured in reduced pressure argon. The breakdown is consistent with parallel plate microwave breakdown measurements2 except if the discharge gap is 1 mm or less. Sustained argon plasmas between 0.5 Torr and 1 atm are found to alter the electromagnetic scattering, suggesting applications in plasma-reconfigurable metamaterials and photonic crystals.