Measurements of Electron Density and Electron Temperature of Arc Discharge Plasmas Containing Metallic Vapors Using Laser Thomson Scattering

SUMMARY Laser Thomson scattering (LTS) was applied to arc discharges generated in the atmosphere to measure electron density (ne) and electron temperature (Te). The electrode gap was 0.8 mm, and the electrode diameter was 1 mm. The applied voltage was 6 kV, the peak current was 600 A, and the decay time of the voltage and current was 25 μs. The spatiotemporal evolution of ne and Te was measured 10, 30, and 50 μs after discharge initiation. At these times, the obtained values of ne and Te were estimated to be in the ranges of (0.8 to 2.0) × 1023 m−3 and 1.0 to 2.2 eV, respectively. These values were consistent with those evaluated using Saha's thermodynamic equation at 1 atm. It was also found that the decay of the arc discharge produced using the tungsten–copper electrodes was much faster than that produced using the tungsten electrodes.