scholarly journals Investigation in the Effect of Applied Voltage and Working Pressure on Some Plasma Parameters in the Positive Column of Dc Glow Discharge

2019 ◽  
Vol 32 (2) ◽  
pp. 9
Author(s):  
Mustafa K. Jassim
Keyword(s):  
Glow Discharge ◽  
Cross Sections ◽  
Applied Voltage ◽  
Positive Column ◽  
Plasma Frequency ◽  
Debye Length ◽  
Experimental Results ◽  
Plasma Parameters ◽  
Working Pressure ◽  
Number Of Particles

     Comsol multiphysics software is established to make a simulation that is comparable with experimental device. by utilizing comsol, the positive column domain of direct-current glow discharge with argon is considered for both of different applied voltage and working gas pressure. The calculations are exhibited by using a precise collision cross sections and Townsend coefficients for the argon. The impacts of voltage and pressure on the Debye length, number of particles in Debye sphere and plasma frequency are calculated and graphically delineated. With this regard to the dependence of plasma parameters on the applied voltage and pressure, some of them are found to be compatible with the experimental results, while others are not. For example, the calculations of the COMSOL shows that the electron temperature is not always decreasing with the increase in the applied voltage, and the Debye length does not give a linearly decreasing relationship but rather an exponentially decreasing relationship. Also, the calculations do not reproduce and match the experimental results for the dependence electron density on working pressure at various potentials.

scholarly journals Spectroscopic Analysis of DC-Nitrogen Plasma Produced using Copper Electrodes

2021 ◽  
pp. 3560-3569
Author(s):  
Ala F. Ahmed ◽  
Ali A. Yousef
Keyword(s):  
Debye Length ◽  
Target Material ◽  
Optical Emission ◽  
Nitrogen Plasma ◽  
Molecular Spectra ◽  
Stark Broadening ◽  
Plasma Parameters ◽  
Working Pressure ◽  
Copper Electrodes ◽  
Copper Material

      This study shows the effects of copper material electrode, applied voltage, and different pressure values on electrical discharge plasma. The purpose of the work is the application of the spectral analysis method to obtain accurate results of nitrogen plasma parameters. By using the optical emission spectroscopy (OES), many N2 molecular spectra peaks appeared in the range from 300 to 480 nm. Also, some additional peaks were recorded, corresponding to atomic and ionic lines for nitrogen, target material, and hydrogen, in all samples. The electron density (ne) was calculated from the measurement of Stark broadening effect, which was found to decrease with increasing pressure from 0.1 mbar to 0.8 mbar. The higher emission intensities occurred at 0.2 mbar working pressure and were reduced with higher pressure. The vibrational temperature (Tvib) for N2 increased from 0.17 to 0.33 eV with increasing the pressure from 0.15 mbar to 0.2 mbar, then decreased to 0.25 eV with increasing the pressure to 0.8 mbar. Other plasma parameters were studied, which are electron temperature (Te), plasma frequency of electron ( ), and Debye length (λD).

THE COMPOSITION OF THE POSITIVE COLUMN OF A HELIUM GLOW DISCHARGE AT INTERMEDIATE PRESSURES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-127-C7-128
Author(s):  
F. Dothan ◽  
Yu. M. Kagan
Keyword(s):  
Glow Discharge ◽  
Differential Equations ◽  
Positive Column ◽  
Molecular Ions ◽  
Time Change ◽  
The Other ◽  
System Of Differential Equations ◽  
Plasma Parameters ◽  
Electron Collisions

The concentration of atomic and molecular ions and metastables is investigated for the positive column of a helium glow discharge. Recently (1,2) the system of differential equations for the helium afterglow describing the time change of these plasma parameters was written and solved. In the stationary positive column we can neglect some processes which are importent in the afterglow. On the other side we must take into account processes of excitation and ionization by electron collisions which can be neglected in the afterglow.

scholarly journals Inverse bremsstrahlung cross section estimated within evolving plasmas using effective ion potentials

2009 ◽  
Vol 75 (3) ◽  
pp. 289-301 ◽  
Author(s):  
F. WANG ◽  
E. WECKERT ◽  
B. ZIAJA
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Vacuum Ultraviolet ◽  
Debye Length ◽  
High Energy ◽  
Plasma Parameters ◽  
Total Cross Sections ◽  
Inverse Bremsstrahlung ◽  
Plasma Environment ◽  
High Energy Absorption

AbstractWe estimate the total cross sections for field-stimulated photoemissions and photoabsorptions by quasi-free electrons within a non-equilibrium plasma evolving from the strong coupling to the weak coupling regime. Such a transition may occur within laser-created plasmas, when the initially created plasma is cold but the heating of the plasma by the laser field is efficient. In particular, such a transition may occur within plasmas created by intense vacuum ultraviolet (VUV) radiation from a free-electron laser (FEL) as indicated by the results of the first experiments performed by Wabnitz at the FLASH facility at DESY. In order to estimate the inverse bremsstrahlung cross sections, we use point-like and effective atomic potentials. For ions modelled as point-like charges, the total cross sections are strongly affected by the changing plasma environment. The maximal change of the cross sections may be of the order of 75 at the change of the plasma parameters: inverse Debye length, κ, in the range κ = 0 − 3 Å−1 and the electron density, ρe, in the range ρe = 0.01 − 1 Å−3. These ranges correspond to the physical conditions within the plasmas created during the first cluster experiments performed at the FLASH facility at DESY. In contrast, for the effective atomic potentials the total cross sections for photoemission and photoabsorption change only by a factor of seven at most in the same plasma parameter range. Our results show that the inverse bremsstrahlung cross section estimated with the effective atomic potentials is not affected much by the plasma environment. This observation validates the estimations of the enhanced heating effect obtained by Walters, Santra and Greene. This is important as this effect may be responsible for the high-energy absorption within clusters irradiated with VUV radiation.

scholarly journals A Study of the Spectroscopic Performance of Laser Produced CdTe(x):S(1-x) Plasma

2019 ◽  
Vol 17 (42) ◽  
pp. 96-102
Author(s):  
Kadhim Abdulwahid Aadim
Keyword(s):  
Optical Properties ◽  
Electron Temperature ◽  
Electron Density ◽  
Optical Transmission ◽  
Plasma Frequency ◽  
Debye Length ◽  
Transmission Method ◽  
Plasma Parameters

Abstract In this work, the plasma parameters (electron temperature (Te), electron density( ne), plasma frequency (fp) and Debye length (λD)) have been studied by using the spectrometer that collect the spectrum of Laser produce CdTe(X):S(1-X) plasma at X=0.5 with different energies. The results of electron temperature for CdTe range 0.758-0.768 eV also the electron density 3.648 1018 – 4.560 1018 cm-3  have been measured under vacuum reaching 2.5 10-2 mbar .Optical properties of CdTe:S were determined through the optical transmission method using ultraviolet visible spectrophotometer within the range 190 – 1100 nm.

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 Spectroscopic Diagnostic of Cadmium Sulfide Plasma Produced By LIBS

2019 ◽  
Vol 17 (42) ◽  
pp. 103-107
Author(s):  
Ala' Fadhil Ahmed
Keyword(s):  
Electron Temperature ◽  
Cadmium Sulfide ◽  
Electron Density ◽  
Plasma Frequency ◽  
Debye Length ◽  
Emission Lines ◽  
Spectral Emission ◽  
Plasma Parameters ◽  
Temperature Electron

Abstract        The current study was carried out to reveal the plasma parameters such as ,the electron temperature ( ), electron density (ne) , plasma frequency (fp), Debye length ( ) , Debye number (   for  CdS to employ the LIBS for the purpose of analyzing and determining spectral emission lines using . The results of electron temperature for CdS range (0.746-0.856) eV , the electron density(3.909-4.691)×1018 cm-3. Finally ,we discuss plasma parameters of CdS  through  nano second  laser generated plasma .

scholarly journals Spectroscopic study the plasma parameters for SnO2 doped ZnO prepared by pulse Nd:YAG laser deposition

2019 ◽  
Vol 17 (42) ◽  
pp. 125-135
Author(s):  
Kadhim Abdulwahid Aadim
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Tin Oxide ◽  
Peak Power ◽  
Plasma Frequency ◽  
Debye Length ◽  
Laser Deposition ◽  
Plasma Parameters ◽  
Analysis Techniques ◽  
Doped Zno

 In this work, plasma parameters such as (electron temperature (Te), electron density (ne), plasma frequency (fp) and Debye length (λD)) were studied using spectral analysis techniques. The spectrum of the plasma was recorded with different energy values, SnO2 and ZnO anesthetized at a different ratio (X = 0.2, 0.4 and 0.6) were recorded. Spectral study of this mixing in the air. The results showed electron density and electron temperature increase in zinc oxide: tin oxide alloy targets. It was located  that  The intensity of the lines increases in different laser peak powers when the laser peak power increases and then decreases when the force continues to increase.

scholarly journals Spectroscopic study the plasma parameters for Pb doped CuO prepared by pulse Nd:YAG laser deposition

2018 ◽  
Vol 16 (38) ◽  
pp. 1-9
Author(s):  
Kadhim A Aadim
Keyword(s):  
Spectroscopic Study ◽  
Electron Temperature ◽  
Optical Transmission ◽  
Optical Emission Spectroscopy ◽  
Plasma Frequency ◽  
Debye Length ◽  
Optical Emission ◽  
Spectroscopy Technique ◽  
Transmission Method ◽  
Plasma Parameters

In this work, plasma parameters such as, the electron temperature )Te(, electron density ne, plasma frequency )fp(, Debye length )λD(and Debye number )ND), have been studied using optical emission spectroscopy technique. The spectrum of plasma with different values of energy, Pb doped CuO at different percentage (X=0.6, 0.7, 0.8) were recorded. The spectroscopic study for these mixing under vacuum with pressure down to P=2.5×10-2 mbar. The results of electron temperature for X=0.6 range (1.072-1.166) eV, for X=0.7 the Te range (1.024-0.855) eV and X=0.8 the Te is (1.033-0.921) eV. Optical properties of CuO:Pb thin films were determined through the optical transmission method using ultraviolet visible spectrophotometer within the range (190 – 1100) nm.

scholarly journals Experimental study of the $ \gamma p \rightarrow K^{0}\Sigma^{+}$, $ \gamma n \rightarrow K^{0} \Lambda$, and $ \gamma n \rightarrow K^{0} \Sigma^{0}$ reactions at the Mainz Microtron

2019 ◽  
Vol 55 (11) ◽  
Author(s):  
C. S. Akondi ◽  
K. Bantawa ◽  
D. M. Manley ◽  
S. Abt ◽  
P. Achenbach ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cross Sections ◽  
Differential Cross ◽  
Legendre Polynomials ◽  
Neutral Kaon ◽  
Experimental Results ◽  
Differential Cross Sections ◽  
Theoretical Predictions ◽  
Photoproduction Reactions ◽  
Insight Into

Abstract.This work measured $ \mathrm{d}\sigma/\mathrm{d}\Omega$dσ/dΩ for neutral kaon photoproduction reactions from threshold up to a c.m. energy of 1855MeV, focussing specifically on the $ \gamma p\rightarrow K^0\Sigma^+$γp→K0Σ+, $ \gamma n\rightarrow K^0\Lambda$γn→K0Λ, and $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 reactions. Our results for $ \gamma n\rightarrow K^0 \Sigma^0$γn→K0Σ0 are the first-ever measurements for that reaction. These data will provide insight into the properties of $ N^{\ast}$N* resonances and, in particular, will lead to an improved knowledge about those states that couple only weakly to the $ \pi N$πN channel. Integrated cross sections were extracted by fitting the differential cross sections for each reaction as a series of Legendre polynomials and our results are compared with prior experimental results and theoretical predictions.

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