Splitting of laser-induced neutral and plasma plumes: hydrodynamic origin of bimodal distributions of vapor density and plasma emission intensity

Abstract

Abstract The splitting of laser-induced plumes into the fast and slow components is usually explained by acceleration of ions by the ambipolar electric field. The kinetic simulations show that the splitting is observed even in neutral plumes due to the snow-plow effect. In plasma plumes, the simulations predict bimodal distributions of plasma emission intensity, where the slow maximum appears due to radiation absorption during the laser pulse, while the fast maximum emerges after the pulse at the plume edge. The snow-plow effect explains why the fast component is observed in a limited range of ambient pressure, exists during a limited time, and is characterized by larger degree of ionization.

Topics & Concepts