Time evolution of the population inversion between (A3Σ+u, v) and (B3Πg,v') states in the positive column of a nitrogen pulsed discharge

Time transients of population difference between these states were measured in a positive column of moderate current nitrogen pulsed gas discharge. Optical gain, due to the population inversion, was present during the first 3-6 \#m\s of the discharge pulse. The population difference was 0.3 x 10\+12\- at the peak current of 1 A. The simple kinetic model, which includes collisions with electrons and molecular nitrogen, reproduces surprisingly accurately the measured time transients of population difference. (Original abstract-amended)