Laser-induced fluorescence of N2( A\,^3Σᵤ^+ ) metastable in N2pulsed positive corona discharge

The density of N 2 ( ) metastable is measured in N 2 pulsed positive corona discharge using time-resolved laser-induced fluorescence (LIF) under atmospheric pressure. The N 2 ( , v '' = 0) state is excited to N 2 ( B 3 Π g , v '' = 4), then the fluorescence from the ( B 3 Π g , v '' = 4) to ( , v '' = 1) band is measured. The discharge occurs in a 12 mm point-to-plane gap. The good agreement between the measured and theoretical LIF excitation spectra shows that the LIF measurement of N 2 ( ) in the pulsed corona discharge is correctly performed. The decay curve of the N 2 ( ) density after discharge cannot be fitted to a single exponential. This indicates that the density of N 2 ( ) metastables mainly decreases by the pooling reaction, , where is electronically excited N 2 . When the discharge voltage is 22 kV, the N 2 ( ) density immediately after discharge is estimated to be less than 6 × 10 13 cm −3 at the midpoint of the 12 mm discharge gap.