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Title: Early-stage plasma dynamics with air ionization during ultrashort laser ablation of metal

Abstract

In this study, the early-stage plasma evolution generated by an ultrashort laser pulse is investigated through pump-probe shadowgraph measurements and simulations. The measurements are performed to show the evolution of the plasma front, while the simulation model is used to further investigate the evolution process and mechanism. Specifically, the laser pulse propagation in air is simulated using the beam propagation method with the slowly varying envelope approximation. The lattice dynamics, the electron dynamics and the multi-scattering event, and the evolution of charged particles (free electrons and ions), are simulated using a molecular dynamics method, a Monte Carlo method, and a particle-in-cell method, respectively. With this simulation model, the refractive index and plasma evolutions are calculated and compared with measured results to validate the simulation model. Different plasma expansion processes, caused by the air ionization, are found with the focal point slightly above and below the target. Air ionization occurs in both cases, but their primary mechanisms are shown to be different.

Authors:
; ;  [1]
  1. School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)
Publication Date:
OSTI Identifier:
22043525
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 18; Journal Issue: 9; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABLATION; AIR; APPROXIMATIONS; IONIZATION; IONS; LASER RADIATION; LIGHT TRANSMISSION; METALS; MOLECULAR DYNAMICS METHOD; MONTE CARLO METHOD; PLASMA; PLASMA DENSITY; PLASMA EXPANSION; PLASMA SIMULATION; PROBES; REFRACTIVE INDEX; SCATTERING

Citation Formats

Hu Wenqian, Shin, Yung C., and King, Galen. Early-stage plasma dynamics with air ionization during ultrashort laser ablation of metal. United States: N. p., 2011. Web. doi:10.1063/1.3633067.
Hu Wenqian, Shin, Yung C., & King, Galen. Early-stage plasma dynamics with air ionization during ultrashort laser ablation of metal. United States. doi:10.1063/1.3633067.
Hu Wenqian, Shin, Yung C., and King, Galen. Thu . "Early-stage plasma dynamics with air ionization during ultrashort laser ablation of metal". United States. doi:10.1063/1.3633067.
@article{osti_22043525,
title = {Early-stage plasma dynamics with air ionization during ultrashort laser ablation of metal},
author = {Hu Wenqian and Shin, Yung C. and King, Galen},
abstractNote = {In this study, the early-stage plasma evolution generated by an ultrashort laser pulse is investigated through pump-probe shadowgraph measurements and simulations. The measurements are performed to show the evolution of the plasma front, while the simulation model is used to further investigate the evolution process and mechanism. Specifically, the laser pulse propagation in air is simulated using the beam propagation method with the slowly varying envelope approximation. The lattice dynamics, the electron dynamics and the multi-scattering event, and the evolution of charged particles (free electrons and ions), are simulated using a molecular dynamics method, a Monte Carlo method, and a particle-in-cell method, respectively. With this simulation model, the refractive index and plasma evolutions are calculated and compared with measured results to validate the simulation model. Different plasma expansion processes, caused by the air ionization, are found with the focal point slightly above and below the target. Air ionization occurs in both cases, but their primary mechanisms are shown to be different.},
doi = {10.1063/1.3633067},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 9,
volume = 18,
place = {United States},
year = {2011},
month = {9}
}