Atmospheric-Pressure Dielectric Barrier Plasma Jets Elongated by Elevating External Electric Field

The discharge characteristics of the atmospheric-pressure plasma jets, generated by a capillary dielectric-barrier-discharge configuration with helium/neon gas flowing through and issuing out into the ambient air in different electric fields, have been investigated by an electron-multiplying CCD. We have compared plasma jets propagating in three configurations: 1) only one unipolar power electrode surrounding the capillary; 2) a ground copper grid placed on the pathway of the jet; and 3) two parallel copper grids placed perpendicular to the jet. Comparing results show that plasma jets can be elongated by elevating external electric field in front of the jets.