Self-absorbed lines analysis of a recombining laser induced aluminum plasma
Résumé
During the recombination of a plasma produced by a nanosecond laser impact on an aluminum alloy target, the resonant spectral lines of Al I exhibit strong deformations owing to the self-absorption. At I mm above the surface and for different time delays after the laser pulse, the intensity and the shape of these experimental lines have been successfully compared with the ones derived from the integration of a self-consistent radiative transfer equation (RTE). Without any equilibrium hypothesis, reliable spatio-temporal evolutions of the involved densities (free electron, upper and lower state of the resonant transitions) are thus obtained between 60 and 180 ns after the laser pulse.