The dynamics of variation in the temperature and the electron number density of a laser plasma in the regime of light–induced combustion is examined using the spectral method. The use of a double image converter (DIC) for recording the spectrum made it possible to obtain the resolution time of the order of 0.1 μs. The fluctuations in the electron number density in discharge at a characteristic frequency of ~10 Hz have been detected, and this indicates a lack of the strict local thermodynamic equilibrium (LTE) in plasma.