Laser plume spectroscopy. 1.Graphite target

Spectral and kinetic characteristics of a plume formed in the vicinity of a graphite target exposed to radiation from a pulsed CO₂ laser at 10.6 μm with a peak power of 9 kW (pulse energy 1.69 J, pulse duration 330 μs at the 0.1 level) in air are studied at room temperature. It is shown that the plume propagating at a right angle to the target surface and at an angle of 45° to the laser radiation is a nonequilibrium gas plasma flow at a temperature of the order of 10 kK; its shape and size are determined by the shape and power of the laser pulse. Emission of C⁺ ions and C₂ molecules is excited in the plume. The temperature and emission are sustained by the energy of the exothermic reaction of association of carbon atoms and the vibrationally excited molecules formed in it.