Electric field gradient in microplasmas

Linear Stark splitting of the Hβ Balmer line components and spatially resolved optical emission spectroscopy (OES) measurements were used to estimate the electric field gradient in the cathode sheath region (∼70 μm long) of an atmospheric pressure direct current argon flow-stabilized microplasma jet. Also, plasma parameters in the negative glow region were investigated by both OES and electrical diagnostics. OES was used to diagnose near-cathode region (negative glow and cathode sheath) of the microplasma jet in order to measure both, the basic discharge parameters, in the plasma bulk, and electric field distribution along the cathode sheath. In addition, the main mechanisms responsible for Hβ spectral line broadenings were investigated.