ABSTRACT
Plasma can be generated in a laboratory under different gas pressures. Atmospheric pressure plasma jets also can be classified into two categories, that is, equilibrium atmospheric pressure plasma jets and nonequilibrium atmospheric pressure plasma jets. Applications in plasma medicine even require that the gas temperature of the plasma be close to room temperature. Regarding spatial-controlling methods, one well-studied technique is to confine the plasma in small dielectric cavities, which limits the discharge to a small volume with dimensions in submillimeter ranges. In addition, diffusion to the walls effectively dampens small fluctuations in the plasma that would otherwise lead to filamentation. To overcome the shortcomings of traditional nonequilibrium atmospheric pressure plasmas, plasmas generated in an open space rather than in a confined discharge gap are needed. When plasma is launched in an open space where the applied electric field is normally quite low, it is extremely difficult to sustain the existence of the nonequilibrium plasma.
