Optical emission spectroscopy measurements within a single microdischarge of a dielectric barrier discharge actuator

This paper reports optical emission spectroscopy measurements resolved laterally within a single microdischarge during the negative half-cycle of a sinusoidally driven dielectric barrier discharge. The maximum values of the reduced electric field, vibrational temperature of $N2(C3Πu)$⁠, and rotational temperature of $N2+(B2Σu+)$ were approximately 300 Td, 3500 K, and 1200 K, respectively. These values were correlated to the outer-edges of the microdischarge near the plasma-dielectric surface interface. These maximum values were significantly greater than measurements made elsewhere within the microdischarge and suggest a strong sheath at the outer-edges of the microdischarge.