N-2(A(3)Sigma(+)(u)) time evolution in N-2 atmospheric pressure surface dielectric barrier discharge driven by ac voltage under modulated regime

The relaxation of N-2(A(3)Sigma(+)(u)) metastable in N-2 ac (5 KHz and 7 KVpp) surface dielectric barrier discharge driven under pulse modulated regime, T-ON=5 ms and T-OFF=20 ms, at atmospheric pressure has been investigated. N-2(A) has been detected by optical-optical double resonance laser induced fluorescence in a space layer (space afterglow) at 1 mm above the discharge electrode. The time evolution clearly shows that in the space afterglow layer N-2(A) builds up and decay in millisecond time scale and does not vary in the voltage cycle.