Temporal Characterization of a Plasma Produced by Interaction of Laser Pulses with Water Solutions

Abstract

The temporal evolution of a plasma formed by the interaction of a Nd-YAG 10 ns laser pulse with the surface of aqueous solutions of CaCl 2 , has been observed by analyzing the variation of the emission spectra of ions and neutral atoms in the time interval after the laser pulse, 500 ns T e using a Saha-Boltzmann analysis. The broadening of the resonance line of CaI at 4227 A was used to deduce the electronic density N e , with the aid of the semiclassical theory of Stark broadening. A value of T e ≈ 28000 K decreasing slightly to 21000 K, and an exponential decay for N e were found, with N e ≈ 1:25 × 10 18 cm -3 at 500 ns and τ e = ( 1200 ± 50 ) ns.