Effects of dielectric barriers in radio-frequency atmospheric glow discharges

This paper reports the effects of introducing dielectric barriers to radio-frequency (RF) atmospheric pressure glow discharges (APGD) that have hitherto employed bare electrodes. The resulting atmospheric RF dielectric barrier discharges (DBD) are experimentally shown to retain their large volume without constriction at very large currents, well above the maximum current at which conventional RF APGD with bare electrodes can maintain their plasma stability. Optical emission spectroscopy is used to demonstrate that larger discharge currents lead to more active plasma chemistry. A complementary computational study is then presented on the dynamics and structures of the RF DBD under different operation conditions. While the RF DBD and conventional RF APGD may present very different electrical signatures in the external circuit, it is shown that their discharge properties, particularly the sheath characteristics, are very similar. Finally, it is demonstrated that thinner dielectric barriers or/and larger excitation frequencies are desirable to maximize the largest permissible discharge current without compromising the plasma stability.