DIAGNOSTICS OF LASER INDUCED GRAPHITE PLASMA UNDER VARIOUS PRESSURES OF AIR, HELIUM AND ARGON

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Zuhaib Haider ◽  
Kashif Chaudhary ◽  
Sufi Roslan ◽  
Jalil Ali ◽  
Yusof Munajat
Keyword(s):  
Electron Density ◽  
Laser Energy ◽  
Ambient Pressure ◽  
Plasma Temperature ◽  
Sample Surface ◽  
Ambient Atmosphere ◽  
Plasma Parameters ◽  
Saha Equation ◽  
Laser Induced Plasma ◽  
Spectroscopic Information

Laser induced plasma provides information about the elemental composition of sample surface and through spectroscopy vital information about plasma dynamics can be obtained. In this paper we present the diagnostics of laser induced plasma at various pressures of Air, Helium and Argon gases. Graphite sample was ablated with Q-smart 850 laser while spectra were captured  Plasma parameters have been calculated by using well known methods based on Saha and Boltzmann equations. Plasma temperature was calculated relative intensity of ionic carbon lines CII 251.21 nm and CII 426.73 nm while the electron density was determined by using spectroscopic information of CI 247.85 nm and CII 426.73 nm emission lines in Saha equation. Plasma temperature and electron density were found to be dependent upon nature and pressure of the ambient atmosphere. Higher temperatures and electron densities were obtained in the presence of Air as ambient environment that is attributed to electrical and physical properties of the Air. Keeping into consideration the plasma expansion in various environments the selection of a suitable ambient pressure can be made on the basis of spectral diagnostics of plasma for a particular laser energy to obtain desirable plasma temperature and electron density suited for certain applications.

scholarly journals Studies on the ns-IR-Laser-Induced Plasma Parameters in the Vanadium Oxide

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Arnab Sarkar ◽  
Raju V. Shah ◽  
D. Alamelu ◽  
Suresh K. Aggarwal
Keyword(s):  
Vanadium Oxide ◽  
Electron Density ◽  
Plasma Temperature ◽  
Spectroscopic Studies ◽  
Decay Rates ◽  
Plasma Parameters ◽  
Boltzmann Plot ◽  
Saha Equation ◽  
Laser Induced Plasma ◽  
Light Pulses

We report spectroscopic studies of laser-induced plasma (LIP) produced by ns-IR-Nd:YAG laser light pulses of different energies onto four different oxides of vanadium (VO, V2O3, VO2, and V2O5) in air under atmospheric pressure. For each oxide with a different oxidation state of vanadium, both electron density and plasma temperature were calculated for different time delays and laser pulse energies. The plasma temperature was determined from Boltzmann plot method, whereas the electron number density was estimated from the Saha equation. The decay rates for plasma temperature as well as electron density were observed to follow power law and were independent of the nature of vanadium oxide. These investigations provide an insight to optimize various parameters during LIBS analysis of vanadium-based matrices.

Atmospheric Influences on Q-Switched Laser Sampling and Resulting Plumes

1971 ◽  
Vol 25 (6) ◽  
pp. 642-652 ◽  
Author(s):  
E. H. Piepmeier ◽  
D. E. Osten
Keyword(s):  
Laser Energy ◽  
Ambient Pressure ◽  
Large Fraction ◽  
Wave Model ◽  
Sample Surface ◽  
Copper Sample ◽  
Atmospheric Plasma ◽  
Limited Region ◽  
Single Spike ◽  
Shock Wave Model

When a 10–100-mJ single-spike Q-switched Nd laser pulse is focused on a copper sample, the presence of an atmosphere affects the spectra, the crater size, and the amount of sample vaporized. At 760 Torr the crater diameter (90 µ) and amount of sample vaporized (35 ng) remain relatively constant while at 1 Torr they both increase with increasing laser energy. Spatial changes in the spectra occur with changes in ambient pressure. The continuum intensity of the limited region just above the sample surface appears to be a better measure of the energy reaching the sample than does the energy of the laser beam. The experimental results appear to be caused by absorption of a large fraction of the laser energy in an atmospheric plasma. A radiation-supported shock-wave model is evaluated in detail and compared briefly with similar models as possible mechanisms for production of the atmospheric plasma. The analytical chemical implications of the experimental and theoretical results are discussed.

scholarly journals Analysis of the enhanced negative correlation between electron density and electron temperature related to earthquakes

2015 ◽  
Vol 33 (4) ◽  
pp. 471-479 ◽  
Author(s):  
X. H. Shen ◽  
X. Zhang ◽  
J. Liu ◽  
S. F. Zhao ◽  
G. P. Yuan
Keyword(s):  
Electric Field ◽  
Electron Density ◽  
Negative Correlation ◽  
Plasma Temperature ◽  
Lower Latitude ◽  
Coupling Mechanism ◽  
Plasma Parameters ◽  
Low Latitudes ◽  
Before And After ◽  
Large Earthquakes

Abstract. Ionospheric perturbations in plasma parameters have been observed before large earthquakes, but the correlation between different parameters has been less studied in previous research. The present study is focused on the relationship between electron density (Ne) and temperature (Te) observed by the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite during local nighttime, in which a positive correlation has been revealed near the equator and a weak correlation at mid- and low latitudes over both hemispheres. Based on this normal background analysis, the negative correlation with the lowest percent in all Ne and Te points is studied before and after large earthquakes at mid- and low latitudes. The multiparameter observations exhibited typical synchronous disturbances before the Chile M8.8 earthquake in 2010 and the Pu'er M6.4 in 2007, and Te varied inversely with Ne over the epicentral areas. Moreover, statistical analysis has been done by selecting the orbits at a distance of 1000 km and ±7 days before and after the global earthquakes. Enhanced negative correlation coefficients lower than −0.5 between Ne and Te are found in 42% of points to be connected with earthquakes. The correlation median values at different seismic levels show a clear decrease with earthquakes larger than 7. Finally, the electric-field-coupling model is discussed; furthermore, a digital simulation has been carried out by SAMI2 (Sami2 is Another Model of the Ionosphere), which illustrates that the external electric field in the ionosphere can strengthen the negative correlation in Ne and Te at a lower latitude relative to the disturbed source due to the effects of the geomagnetic field. Although seismic activity is not the only source to cause the inverse Ne–Te variations, the present results demonstrate one possibly useful tool in seismo-electromagnetic anomaly differentiation, and a comprehensive analysis with multiple parameters helps to further understand the seismo–ionospheric coupling mechanism. \\keywords{Ionosphere (plasma temperature and density)}

scholarly journals X-ray and ion emission studies from subnanosecond laser-irradiated SiO2 aerogel foam targets

2017 ◽  
Vol 35 (3) ◽  
pp. 505-512 ◽  
Author(s):  
C. Kaur ◽  
S. Chaurasia ◽  
A.A. Pisal ◽  
A.K. Rossall ◽  
D.S. Munda ◽  
...  
Keyword(s):  
Laser Energy ◽  
Laser System ◽  
Line Emission ◽  
Plasma Temperature ◽  
X Rays ◽  
Plasma Parameters ◽  
X Ray ◽  
Spectral Ranges ◽  
Ion Emission

AbstractIn this experiment, a comparative study of ion and X-ray emission from both a SiO2 aerogel foam and a quartz target is performed. The experiment is performed using Nd:glass laser system operated at laser energy up to 15 J with a pulse duration of 500 ps with focusable intensity of 1013–1014 W/cm2 on target. X-ray fluxes in different spectral ranges (soft and hard) are measured by using X-ray diodes covered with Al filters of thickness 5 µm (0.9–1.56 keV) and 20 µm (3.4–16 keV). A 2.5 times enhancement in soft X-ray flux (0.9–1.56 keV) and a decrease of 1.8 times in hard X rays (3.4–16 keV) for 50 mg/cc SiO2 aerogel foam is observed compared with the solid quartz. A decrease in the flux of the K-shell line emission spectrum of soft X rays is noticed in the case of the foam targets. The high-resolution K-shell spectra (He-like) of Si ions in both the cases are analyzed for the determination of plasma parameters by comparing with FLYCHK simulations. The estimated plasma temperature and density are Tc = 180 eV, ne = 7 × 1020 cm−3 and Tc = 190 eV, ne = 4 × 1020 cm−3 for quartz and SiO2 aerogel foam, respectively. To measure the evolution of the plasma moving away from the targets, four identical ion collectors are placed at different angles (22.5, 30, 45, and 67.5°) from target normal. The angular distribution of the thermal ions are scaled as cosnθ with respect to target normal, where n = 3.8 and 4.8 for the foam and quartz, respectively. The experimental plasma volume measured from the ion collectors and shadowgraphy images are verified by a two-dimensional Eulerian radiative–hydrodynamic simulation (POLLUX code).

scholarly journals Characterizing laser-induced plasma generated from MgO/PVA solid targets-=SUP=-*-=/SUP=-

2019 ◽  
Vol 127 (7) ◽  
pp. 158
Author(s):  
T.K. Hamad ◽  
A.S. Jasim ◽  
H.T. Salloom
Keyword(s):  
Laser Energy ◽  
Second Harmonic ◽  
Plasma Electron ◽  
Poly Vinyl Alcohol ◽  
Laser Irradiance ◽  
Plasma Parameters ◽  
Laser Induced Plasma ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
532 Nm

AbstractThis contribution reports on the characterization of laser-induced plasma generated from the surface of magnesium oxide dispersed in Poly (vinyl alcohol) (MgO/PVA) pellet using laser induced breakdown spectroscopy. For this purpose, Nd:YAG Q-switched pulsed laser with energy ranging from 50 to 250 mJ, operating at both fundamental (1064 nm) and second harmonic (532 nm) was focused on the sample to generate plasma. Based on experimental results, emission lines of magnesium have been used to calculate the plasma parameters. The plasma electron temperature as a function of laser energy ranged from (8596–8900) K and (8000-8700) K, and the electron density from (1.12–1.8) × 10^16 cm^–3, (2.9–4.5) × 10^16 cm^–3 measured at 1064 nm and 532 nm, respectively. Although these values increased with the increase in laser irradiance, they showed different rates of increase with different wavelength dependency.

A simple method for laser-induced plasma diagnostics under condition of optically thin

2016 ◽  
Vol 30 (16) ◽  
pp. 1650197 ◽  
Author(s):  
Jian He ◽  
Qingguo Zhang
Keyword(s):  
Electron Density ◽  
Plasma Diagnostics ◽  
Plasma Temperature ◽  
Spectral Lines ◽  
Simple Method ◽  
Laser Induced Plasma ◽  
Spectral Diagnostics ◽  
Order Of Magnitude ◽  
Density Diagnostics ◽  
Copper Plasma

For simple plasma diagnostics for laser-induced plasma (LIP) under the condition of optically thin, taking the Cu I spectral lines produced by the laser-induced copper plasma, we investigate a simple method for temperature and electron density diagnostics, and we obtain the plasma temperature which has 104 K order of magnitude and the averaged electron density is [Formula: see text], which are in agreement with that obtained by other methods. This investigation will be significant for spectral diagnostics for LIP.

scholarly journals Influence of Gas Type on the Laser Produced Graphite Plasma

2021 ◽  
Vol 2114 (1) ◽  
pp. 012030
Author(s):  
H Adil A Alazawi ◽  
Q Adnan Abass
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Plasma Frequency ◽  
Laser Energy ◽  
Debye Length ◽  
Optical Emission ◽  
Plasma Parameters ◽  
Pulse Laser Energy ◽  
Electron Density Increase ◽  
Ionic Emission

Abstract Plasma graphite creation by a pulsed Nd: YAG laser with a wavelength of 1064nm to a target in vacuum in two cases (Argon, Air) with varied gas pressures and the resulting spectrum was diagnosed using optical emission spectroscopy for the wavelength range 320-740nm electron temperature Te and electron density ne Debye lengthλD , and plasma frequency f p were calculated. The results showed that increasing the pulse laser energy causes all plasma parameters of both gases under study to increase, as well as a rise in the emission line intensity. The ionization energy of target atoms determines the presence of an element’s atomic and ionic emission lines in the emission spectrum, increase in pressure decreases the electron temperature, and Debye length, also plasma frequency and electron density increase, as it has been proven that the type of gas does not affect the properties of plasma.

scholarly journals Plasma Temperature and Electron Density of Dry µ-EDM on Stainless Steel and Silicon: A Comparison

2011 ◽  
Vol 5 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Kanmani Subbu Subbian ◽  
◽  
Ramkumar Janakarajan ◽  
Dhamodaran Santhanagopalan ◽  
Keyword(s):  
Stainless Steel ◽  
Electron Density ◽  
Plasma Temperature ◽  
Optical Emission ◽  
Machining Process ◽  
Lead Times ◽  
Line Pair ◽  
Plasma Parameters ◽  
Pair Method ◽  
2D And 3D

Fabricating micro/nano-features in devices and largescale production with short lead times is challenging, and many individual and hybrid processes have been developed to meet this challenge. Among nonconventional processes, micro-electric discharge machining (µ-EDM) has many advantages due to the possibility of precise and accurate 2D and 3D machining of complex shapes. Dry µ-EDM is used to process assembled or semi-assembled products. Attempts are being made to improve the µ-EDM process, and further improvement is possible through better understanding the role of discharge plasma in the machining process. We studied plasma and crater characteristics during dry µ-EDM, calculating plasma parameters for different discharge energies using optical emission spectroscopy. Line pair method and modified Saha equations are used to calculate plasma temperature and electron density respectively. Craters were morphologically analyzed using scanning electron microscopy (SEM), and plasma and crater characteristics on stainless steel and silicon were compared.

scholarly journals Spectroscopic Diagnosis of the CdO:CoO Plasma Produced by Nd:YAG Laser

2021 ◽  
pp. 2948-2955
Author(s):  
Maryam M. Shehab ◽  
Kadhim A. Aadim
Keyword(s):  
Electron Temperature ◽  
Nd:Yag Laser ◽  
Laser Energy ◽  
Focal Length ◽  
Optical Emission ◽  
Ratio Method ◽  
Plasma Parameters ◽  
Optical Emission Spectrum ◽  
Boltzmann Plot ◽  
Laser Induced Plasma

      In this paper, the optical emission spectrum (OES) technique was used to analyze the spectrum resulting from the (CdO:CoO)  plasma in air, produced by Nd:YAG laser with λ=1064 nm, τ=10 ns, a focal length of 10 cm, and a range of energy of 200-500 mJ. We identified laser-induced plasma parameters such as electron temperature (Te) using Boltzmann plot method, density of electron (ne), length of Debye (λD), frequency of plasma (fp), and number of Debye (ND), using two-Line-Ratio method. At a mixing ratio of X= 0.5, the (CdO:CoO) plasma spectrum was recorded for different energies. The results of plasma parameters caused by laser showed that, with the increase in laser energy, the values of Te, ne and fp were increased, while the value of λD was decreased. The calculated electron temperature value was in the range of 0.449-0.619 eV at ratio X=0.5

scholarly journals Spectroscopic Diagnostics of Plasma parameter in Laser Induced Plasma using PbO Lines

2019 ◽  
Vol 24 (2) ◽  
pp. 63
Author(s):  
Anas A. Abdullah1 ◽  
Sabre J. Mohammed1 ◽  
Ghuson H. Mohammed2
Keyword(s):  
Electron Density ◽  
Optical Emission Spectroscopy ◽  
Plasma Parameter ◽  
Laser Energy ◽  
Wave Length ◽  
Optical Emission ◽  
Optical Emission Spectrum ◽  
Electrical Field ◽  
Excitation Rate ◽  
Laser Induced Plasma

The optical emission spectrum of produced plasma was studied using pulse laser, where the effect of laser energy at a wavelength of 1064nm  was studied on lead oxide that produced by optical emission spectroscopy at different laser energy from 500 to 900 mJ. It was found that the intensity for Pb I and Pb II lines increase with increasing laser energy, but with different ratio, as a result increasing the excitation rate with increasing the number of falling photons. The wave length was recorded at highest laser Energy produced from Pb II which was equal to 666.02 nm. It can be seen that The height of peaks increase with increasing laser energy due to the effect of increasing the Electrical field induced by increasing Electrons density and the temperature of electron (Te) and electron density (ne) increase from 1.222×1018 cm-3 to 1.444×1018 cm-3 with increasing laser energy from  500 to 900 mJ respectively as a result of increasing number of falling photons which lead to increase in the electron density.   http://dx.doi.org/10.25130/tjps.24.2019.033   

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