Propagation dynamics of laterally colliding plasma plumes in laser-blow-off of thin film

摘要

We report a systematic investigation of two plume interactions at different spatial separation (3-7 mm) in laser-blow-off. The plasmas plumes are created using Laser-blow-off (LBO) scheme of a thin film. The fast imaging technique is used to record the evolution of seed plasmas and the interaction zone which is formed as a result of interaction of the two seed plasmas. Time resolved optical emission spectroscopy is used to study evolution of optical emissions of the species present in the different regions of the plasmas. Neutral Li emissions (Li I 670.8nm (2s 2S1/2 2p 2P3/2, 1/2) and Li I 610.3 nm (2p ~2P_(3/2, 1/2) ← 3d ~2D_(3/2, 5/2))) are dominant in the plasmas but significant differences are observed in the emission and estimated plasma parameters of the seed and the interaction zone. The transport of plasma species from the seed plasmas to the interaction zone is discussed in the terms of plume divergence, kinetic energy of particles, and ion acoustic speed. An attempt is made to understand the formation and dynamics of the interaction zone in the colliding LBO seed plasmas.