Velocity Form Calculations of Generalized Oscillator Strengths for 3s→ (3p, 4p, 5p, 6p) Dipole Transitions of Atomic Sodium in Debye Plasma

In this paper, the generalized oscillator strengths (GOSs) of excitations of atomic sodium from ground state to 2p63s0 (3p, 4p, 5p, 6p) states, immersed in Debye plasma, were calculated by using wavefunctions which were obtained numerically from the restricted Hartree-Fock (RHF) equation. This RHF equation employs the local density approach for exchange interactions including plasma Debye screening. Theoretical RHF and random phase approximation with exchange (RPAE) velocity calculations have shown that the GOSs for excitations to 3 s0(3 p,4 p,5 p,6 p)depend on the plasma Debye screening effects, as shown by the reduction in the GOS amplitude with decreasing Debye length λD. The agreement between the present RPAE V results for the transitions 3 s→3 s0(3 p,4 p,5 p)and the length calculations of Martínez-Flores was satisfactory. Correlation effects were found quite to be significant in the vicinity of the maxima of the GOS of the 3 s→3 s0(4 p,5 p,6 p)excitations by using the RPAE V approach. We note the poor influence of many electron correlations on the GOS of (3 s→3 p)transition with the same principal quantum number. Finally, we comment that the RPAE V calculations are useful in investigating electron correlation effects on the transition GOS of atomic sodium planted in Debye plasma. The present velocity results also reveal that the 3 s→3 s0(5p, 6p)transition GOSs tend to be delocalized due to more significant screening effects at Debye lengths λD=20and 30 a.u. for excited subshells 5p and 6p, respectively. We report here novel results of GOS for 3 s→3 s06ptransition obtained from different Debye lengths.

Design of a variable frequency comb reflectometer system for the ASDEX Upgrade tokamak

Comb reflectometers offer the advantage of measuring several radial positions in plasma simultaneously.This allows for the investigation of fast timescales during L-H transitions,I-phases,I-mode bursts,transients during heat wave propagation,etc.A drawback of many present-day systems is that they use a fixed frequency difference between the probing frequencies.Hence,although the central probing frequency can be varied,the probing frequency difference is usually fixed.The new design presented in this work uses an advanced microwave generation and detection scheme,which allows for arbitrary probing frequencies and probing frequency separations.

VOCs Destruction by Plasma Catalyst Coupling Using AL-KO PURE Air Purifier on Industrial Scale

We have investigated in this study the destruction of acetone and toluene with AL-KO PURE air purifier (AL-KO PURE) on industrial scale. In the case of acetone, 100% pollutant abatement is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.5 ppm (1187 μg/m3, about 7 times higher than the average living room level). This corresponds to 0.2 μmol/s with a flow rate of 38.42 m3/h. The regeneration of a saturated catalytic filter was also tested. When the catalytic filter of AL-KO PURE is fully saturated with acetone, a 100% acetone destruction efficiency can be achieved at 0.46 ppm concentration with 25% fan speed. Moreover the second pollutant, toluene, has been also studied. 100% toluene abatement also is achieved with AL-KO PURE over more than 80 hours (the test duration time) at the high level concentration of 0.2 ppm (811 μg/m3, 0.087 μmol/s with a flow rate of 38.42 m3/h). Finally, the availability for the simultaneous removal of both pollutants, acetone and toluene, has been also studied.

A Simplified Numerical Study of the Kr/Cl_2 Plasma Chemistry in Dielectric Barrier Discharge

In this paper, the generation of excimers and exciplexe radiation in mixtures of rare gas with halogen by homogeneous dielectric barrier discharge （DBD） is investigated. The typical characteristics of an excilamp based on KrCI＊ exciplexe molecules and the kinetic processes for the formation and the decay of this molecules in the Kr/Cl2 mixture are studied. The computer model developed is based on the Kr/Cl2 mixture chemistry, the equivalent electric circuit and the Boltzmann equations. The importance in the kinetic processes of some species such as the metastable state of Krypton （Kr＊（3P0,2）） and the negative ion of chloride （C1-） is considered. The results illustrate the time variations of charged species （ne, Kr＋, CI-, Cl＋, Cl＋, Kr＋）, excited atoms and molecules （Kr＊（3p0,2）, Kr＊（3P1）, Cl＊, Cl2）, the excimers （Kr, KrCl＊（B）, KrCI＊（C）, Kr2Cl＊） and the UV photon concentrations （in 222 nm, 235 nm, 258 nm and 325 nm range）. The effects of chlorine concentration and the total gas pressure in the Kr-Cl2 discharge on the electric parameters and radiation emissions are investigated.

Methane conversion using a dielectric barrier discharge reactor at atmospheric pressure for hydrogen production

In the present paper, we carried out a theoretical study of dielectric barrier discharge（DBD）filled with pure methane gas. The homogeneous discharge model used in this work includes a plasma chemistry unit, an electrical circuit, and the Boltzmann equation. The model was applied to the case of a sinusoidal voltage at a period frequency of 50 kHz and under a gas pressure of 600 Torr. We investigated the temporal variation of electrical and kinetic discharge parameters such as plasma and dielectric voltages, the discharge current density, electric field, deposited power density, and the species concentration. We also checked the physical model validity by comparing its results with experimental work. According to the results discussed herein, the dielectric capacitance is the parameter that has the greatest effect on the methane conversion and H_2/CH_4 ratio. This work enriches the knowledge for the improvement of DBD for CH_4 conversion and hydrogen production.

On the electron sheath theory and its applications in plasma–surface interactions

In this work,an improved understanding of electron sheath theory is provided using both fluid and kinetic approaches while elaborating on their implications for plasma–surface interactions.A fluid model is proposed considering the electron presheath structure,avoiding the singularity in electron sheath Child–Langmuir law which overestimates the sheath potential.Subsequently,a kinetic model of electron sheath is established,showing considerably different sheath proflles in respect to the fluid model due to non-Maxwellian electron velocity distribution function and flnite ion temperature.The kinetic model is then further generalized and involves a more realistic truncated ion velocity distribution function.It is demonstrated that such a distribution function yields a super-thermal electron sheath whose entering velocity at the sheath edge is greater than the Bohm criterion prediction.Furthermore,an attempt is made to describe the electron presheath–sheath coupling within the kinetic framework,showing a necessary compromise between a realistic sheath entrance and the inclusion of kinetic effects.Finally,the secondary electron emissions induced by sheath-accelerated plasma electrons in an electron sheath are analysed and the influence of backscattering is discussed.

Numerical investigation of Ar–NH3 mixture in homogenous DBDs

In this paper, a study of homogenous dielectric barrier discharge Ar–NHwas made in order to investigate the electrical and the physical characteristics of homogenous discharge at atmospheric pressure. The discharge model includes the electrical module and the chemical kinetic module. The results obtained by the present model were compared with experimental work. The evolution of the plasmas voltage, the species densities, and the concentration of charged species are analyzed and discussed.

Investigation of electron beam effects on L-shell Mo plasma produced by a compact LC generator using pattern recognition

In this paper,the effects of an electron beam on X-pinch-produced spectra of L-shellMoplasma are investigated for the first time by principal component analysis(PCA);this analysis is compared with that of line ratio diagnostics.A spectral database for PCA extraction is arranged using a non-Local Thermodynamic Equilibrium(non-LTE)collisional radiative L-shell Mo model.PC vector spectra of L-shell Mo,including F,Ne,Na and Mg-like transitions are studied to investigate the polarization types of these transitions.PC1 vector spectra of F,Ne,Na and Mg-like transitions result in linear polarization of Stokes Q profiles.Besides,PC2 vector spectra show linear polarization of Stokes U profiles of 2p^(5)3s of Ne-like transitions which are known as responsive to a magnetic field[Trabert,Beiersdorfer,and Crespo Lo´pez-Urrutia,Nucl.InstrumMethods Phys.Res.,Sect.B 408,107–109(2017)].A 3D representation of PCA coefficients demonstrates that addition of an electron beam to the non-LTE model generates quantized,collective clusters which are translations of each other that follow V-shaped cascade trajectories,except for the case f=0.0.The extracted principal coefficients are used as a database for an Artificial Neural Network(ANN)to estimate the plasma electron temperature,density and beam fractions of the time-integrated,spatially resolved L-shellMoX-pinch plasma spectrum.PCA-based ANNs provide an advantage in reducing the network topology,with a more efficient backpropagation supervised learning algorithm.The modeled plasma electron temperature is about Te;660 eV and density n_(e)=1×10^(20) cm^(-3),in the presence of the fraction of the beams with f-0.1 and centered energy of 5 keV.