Alpha-Line Characterization of Electronic Density in Plasmas Generated by Laser Shock Processing

Abstract

Laser Shock Processing (LSP) is based on the application of a high intensity pulsed Laser beam ( I > 109 W/cm2 ; T < 50 ns) on a metallic target forcing a sudden vaporization of its surface into a high temperature and density plasma that immediately develops inducing a shock wave propagating into the material. One of the physical processes that should be deeply studied consists of the interaction between plasma and the surface of the material and how it can be affected by mechanisms different from the mere mechanical interaction with the shock wave. To study such process, it is necessary to know the properties of plasma generated by the interaction between the laser and the metallic surface. This type of plasma studies have been realized for years and they are known as Laser Induced Breakdown Spectroscopy (LIBS). The difference of this research with the classical LIBS technique either in air or in liquid medium, depends on the shielding the flow water applies on the emission of every present species in the plasma but for the Hydrogen emission.