Estimation of Electron Density and Temperature by Continuum Spectrum in a Moving Atmospheric-Pressure Nonthermal-Equilibrium Argon Plasma Bullet

A moving atmospheric-pressure nonthermal-equilibrium argon plasma bullet was investigated by emission spectrum and plasma current. Moving plasma changes spatially and temporally. Therefore, it is necessary to consider the time variation of plasma in measurement. Thus, the validity of the electron density estimated by the two types of optical and electrical measurement methods was examined. The electron density and temperature are estimated from the analysis of continuum spectrum (CS). Moreover, the electron density was also estimated from the relationship between the current and the propagation velocity of the plasma luminescence. The plasma current was estimated from the power-line currents with and without plasmas. The propagation velocity of the plasma luminescence was measured by applying the time-of-flight (ToF) method on the observed emission intensity. The electron density estimated from the analysis of CS is comparable to that estimated from the effective peak plasma current. Consequently, the analysis of CS is applicable to a moving plasma bullet.