Temporal follow up of the LTE conditions in aluminum laser induced plasma at different laser energies

Galmed, A. H.; Harith, M. A.

doi:10.1007/s00340-008-2971-0

Cited by 70 publications

(26 citation statements)

References 29 publications

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“…Radziemski et al 22 have compared the two temperatures temporally at atmospheric pressure and have mentioned that the two temperatures are quasi equal and the plasma is in LTE after the first 1µs. Although that the laser power density used in this work is much lower than that used by Galmed et al, 12 our results about the two temperatures at atmospheric pressure are indicating that the LTE is verified at all distances which is similar to the result found by Galmed.…”

Section: A Spatial Behavior Of Excitation and Ionic Temperaturessupporting

confidence: 80%

“…At 10 Pa and a distance of 2 mm, the electron density is high and the collisional process becomes more dominant than the radiative mechanism, hence, the LTE condition could be valid to describe the plasma. 12,30 Farther than 2 mm the electron density decreases exponentially and does not follow 1/z law which indicate that the plasma does not propagate freely and the expansion of the plasma plume is not one dimensional as it is considered in other works. 31,32 Therefore, the radiative process starts to compete with the collisional one and the collisional-radiative model (CR) could be better to describe the plasma.…”

Section: B Spatial Behavior Of Electron Densitymentioning

confidence: 96%

“…At higher Ar pressures (10 4 , 10 5 Pa), the two temperatures are almost equal. The difference between the ionic and excitation temperatures has been explored temporally in the delay time range (500 to 5000 ns) by Galmed et al 12 for different laser energies at atmospheric pressure. They concluded that for low power density (2 × 10 11 W/cm 2 ), the ionic temperature is higher than the excitation temperature while at high power density (8 × 10 11 W/cm 2 ) the two temperatures are quasi-equal and according to their results LTE condition is verified over all the temporal range.…”

Section: A Spatial Behavior Of Excitation and Ionic Temperaturesmentioning

confidence: 99%

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Investigation of local thermodynamic equilibrium of laser induced Al2O3–TiC plasma in argon by spatially resolved optical emission spectroscopy

2016

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Plasma plume of Al2O3–TiC is generated by third harmonic Q-switched Nd:YAG nanosecond laser. It is characterized using Optical Emission Spectroscopy (OES) at different argon background gas pressures 10, 102, 103, 104 and 105 Pa. Spatial evolution of excitation and ionic temperatures is deduced from spectral data analysis. Temporal evolution of Ti I emission originated from different energy states is probed. The correlation between the temporal behavior and the spatial temperature evolution are investigated under LTE condition for the possibility to use the temporal profile of Ti I emission as an indicator for LTE validity in the plasma.

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Section: A Spatial Behavior Of Excitation and Ionic Temperaturessupporting

confidence: 80%

Section: B Spatial Behavior Of Electron Densitymentioning

confidence: 96%

Section: A Spatial Behavior Of Excitation and Ionic Temperaturesmentioning

confidence: 99%

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Investigation of local thermodynamic equilibrium of laser induced Al2O3–TiC plasma in argon by spatially resolved optical emission spectroscopy

2016

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“…In this, the detection sensitivity of the system can be significantly enhanced through the optimisation of several critical parameters. Here the plasma production is influenced by laser parameters (intensity, pulse duration, and wavelength) [7][8][9], the physical properties of the target material (z-number, ionisation potential, reflectivity and thermal conductivity), and by the ambient conditions. There are several ways to improve the performance of LIBS.…”

Section: Introductionmentioning

confidence: 99%

Effect of applying static electric field on the physical parameters and dynamics of laser-induced plasma

Elhassan

Elmoniem

Kassem

et al. 2010

Journal of Advanced Research

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In order to improve the performance of the LIBS technique -in particular its sensitivity, reproducibility and limit of detection -we studied the effect of applying a static electric field with different polarities on the emission spectra obtained in a typical LIBS set-up. The physical parameters of the laserinduced plasma, namely the electron density N e and the plasma temperature T e , were studied under such circumstances. In addition to the spectroscopic analysis of the plasma plume emission, the laser-induced shock waves were exploited to monitor the probable changes in the plasma plume dynamics due to the application of the electric field. The study showed a pronounced enhancement in the signal-to-noise (S/N) ratio of different Al, neutral and ionic lines under forward biasing voltage (negative target and positive electrode). On the other hand, a clear deterioration of the emission line intensities was observed under conditions of reversed polarity. This negative effect may be attributed to the reduction in electron-ion recombinations due to the stretched plasma plume. The plasma temperature showed a constant value in the average with the increasing electric field in both directions. This effect may be due to the fact that the measured values of T e were averaged over the whole plasma emission volume. The electron density was observed to decrease slightly in the case of forward biasing while no significant effect was noticed in the case of reversed biasing. This slight decrease in N e can be interpreted in view of the increase in the rate of electron-ion recombinations due to the presence of the electric field. No appreciable effects of the applied electric field on the plasma dynamics were noticed.

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“…The McWhirter criterion (necessary but not sufficient) gives the lower limit of the electron density satisfactory for the LTE condition for analytical purposes as follows [21,22]: where, N e is the critical electron density, T e (K) is the plasma temperature, and ΔE (eV) is the maximum energy transition between the upper and lower levels.…”

Section: Local Thermodynamic Equilibriummentioning

confidence: 99%

Quantitative analysis of Cu and Co adsorbed on fish bones via laser-induced breakdown spectroscopy

Rezk

Galmed

Abdelkreem

et al. 2016

Optics & Laser Technology

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Temporal follow up of the LTE conditions in aluminum laser induced plasma at different laser energies

Cited by 70 publications

References 29 publications

Investigation of local thermodynamic equilibrium of laser induced Al2O3–TiC plasma in argon by spatially resolved optical emission spectroscopy

Investigation of local thermodynamic equilibrium of laser induced Al2O3–TiC plasma in argon by spatially resolved optical emission spectroscopy

Effect of applying static electric field on the physical parameters and dynamics of laser-induced plasma

Quantitative analysis of Cu and Co adsorbed on fish bones via laser-induced breakdown spectroscopy

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