Time dependence measurement of electron density and temperature of a 60 Hz nonequilibrium atmospheric pressure plasma by laser Thomson scattering

A nonequilibrium atmospheric pressure plasma excited by 60 Hz ac power was diagnosed by laser Thomson scattering. We studied the electron temperature ($T_{e})$ and density ($n_{e})$ in one ac cycle. The results showed that the plasma generated in a frequency of 120Hz, and occupied half of every half ac cycle with about 1ms delay shift compared with ac voltage waveform. During the discharge periods the $T_{e}$ was almost same about 1.5eV, and $n_{e}$ reached its maximum around peak value of ac voltage, after that decreased with the decreasing of ac voltage, which changes from about 5.0$\times $10$^{14}$cm$^{-3}$ to 2.0$\times $10$^{14}$cm$^{-3}$.