ArI and H$_{\beta }$ Line Broadening in Microplasma Jet and DC Microhollow Cathode Plasmas at Atmospheric Pressure

Direct current microplasma jet and microhollow cathode discharges are studied in argon at atmospheric pressure. The microplasma jet consists of tungsten-carbide needle and a metallic plate. Various needle diameters (150 to 1000$\mu $m) were used. The needles are operated as the cathode or anode. Microhollow cathode is a sandwich of metal-dielectric-metal with a micro hole (200 to 1000$\mu $m diameter). Charged plasma particles induce broadening of lines due to Stark effect. The electric microfield also induces broadening of ArI 603.213nm and 565.070nm lines. These two lines are sensitive to Van der Waals and Stark broadening. The broadening of these two lines enables us to evaluate gas temperature, electron temperature and density. These parameters are dependent on discharge operating mode: abnormal (low and high current) and normal. Calculations take into account the characteristic of two-temperature plasma and the ion dynamic effect in lines broadening The results for microjets are well similar to those obtained also with Balmer H$_{\beta }$ and H$_{\alpha }$lines in Ar-2{\%}H$_{2}$ mixture gases: n$_{e}$ from 4.0x10$^{14}$ to 2.0x10$^{15}$cm$^{-3}$ and T$_{e} \quad \cong $ 0.6eV. As anode, the needle generates microjets with T$_{g}$ from 400 to 900K, at high current (from 20 to 130mA).