Influence of Gas Pressure on the Magnetized Plasma Parameters of Laser-Induced Breakdown

In this study, the effect of environment gas and working pressure of laser-induced breakdown spectroscopy (LIBS) from ZnO: Al composite target (AZO) enhanced by an external magnetic field on the magnetized characteristics and emission spectra of plasma were investigated. The plasma was induced by a Q-switched nanosecond Nd: YAG laser at a constant pulse laser energy of 300 mJ at different pressures of 0.08, 0.2, 0.4, and 760 Torr in air and argon gas. The atomic and ionic emission lines increased in intensity directly with the working pressure. The plasma temperature ( T e ) and electron number density ( n e ) were determined at the different environmental conditions according to Boltzmann-Plot, and Stark broadening effect, respectively. The n e increased with increasing pressure as a result of increasing electron-atom collisions. While T e reduced with working pressure. The plasma parameters in different conditions satisfied the plasma criteria. The line profile appeared with high broadening at atmospheric pressure compared with vacuumed plasma. The Larmur radius reduced while the confinement factor β increased with working pressure. From another hand, using Ar instead of air caused to slightly reduced in n e at low pressure of 0.08 Torr, and slightly increased at 0.4 Torr pressure. While the T e has the opposite behavior. Due to the evidence variation of plasma number density with pressure, the plasma frequency values increased with increasing the pressure, with higher values in Ar than air at 0.4 Torr, while slightly lower in Ar than air at 0.08 Torr. λ D and N d have opposite behavior with working pressure.