Numerical Analysis of Argon Excitation by Nd: Glass Laser
Bassam Ghazolin, H.S. Ayoub, Mohamed Eassa and Yahia Hamdy Elbashar
In this study a general numerical modeling of electron cascade processes leading to breakdowns in argon gas. The model was succeeded in interpret the breakdown phenomenon in argon gas over pressure range (1.368×102 torr to 2.35×103 torr) irradiated with the second harmonic of the Nd: Glass laser of wavelength 0.53 μm and pulse duration 15 ns. The electron mean energy as a function of time at law pressure is increases as a result of the increase of the rate of energy gain by the free electrons. However, the peak the net rate of producing high energy electrons decreases. Since electrons mostly expand their energies in undergoing inelastic collisions with a neutral gas atoms yielding more electrons with low energies. The higher of the electron mean energy values observed in is meanly due to the high laser intensity required to overcome diffusion losses. On the other hand, at high pressure are almost similar during the first half of the laser flash. The results show considerable increase reaching to a value of around 4.7eV at the end of the laser flash. Moreover, the excitation rate at the low and high pressures respectively. Confirms the important role played by diffusion losses during the first stage of laser flash. However, the influence of diffusion and recombination losses on the ionization growth rate in argon gas. The relation between the ionization rate pe+r electron as a function of time, which indicates the effect of diffusion losses during this time interval.
Keywords: lasers, argon gas, numerical modeling, Nd: Glass laser