Abstract: The effect of dielectric constant of tube on characteristics of atmospheric pressure Ar cold plasma jets has been investigated by using two-dimensional fluid model. It is shown that there are different features of plasma jets in and out of the tube. In the dielectric tube, the ionization wave accelerates firstly and then decelerates as it is propagating along with the dielectric surface, giving rise to the ring structure. The larger the dielectric constant, the smaller jet radius of the ring structure, the lower the electron density, and the smaller jet propagation velocity. When the plasma jet leaves the dielectric tube, its velocity increases dramatically and then slows down. The larger the dielectric constant is, the larger the acceleration is. The ring structure shrinks all the time and vanishes eventually in the jet propagating process. These results provide certain guiding significance for design and optimization of cold plasma sources.

Key words: cold atmospheric pressure plasma jet, dielectric constant, fluid model