Previous Issue
Volume 7, September
 
 

Plasma, Volume 7, Issue 4 (December 2024) – 5 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Select all
Export citation of selected articles as:
9 pages, 6638 KiB  
Article
The Influence of the Ionic Core on Structural and Thermodynamic Properties of Dense Plasmas
by Tomiris Ismagambetova, Mukhit Muratov and Maratbek Gabdullin
Plasma 2024, 7(4), 858-866; https://doi.org/10.3390/plasma7040046 - 31 Oct 2024
Viewed by 342
Abstract
In this paper, a new ion–ion screened potential was numerically calculated, which takes into account the ion core effect, i.e., the influence of strongly bound electrons. The pseudopotential model describing the shielding of ion cores and the screening using the density response function [...] Read more.
In this paper, a new ion–ion screened potential was numerically calculated, which takes into account the ion core effect, i.e., the influence of strongly bound electrons. The pseudopotential model describing the shielding of ion cores and the screening using the density response function in the long wavelength approximation were used. To study the influence of this ion core effect on dense plasma’s structural and thermodynamic properties, the integral Ornstein–Zernike equation was solved in the hypernetted chain approximation. Our results show that the ion core has a significant impact on ionic radial distribution functions and thermodynamic properties when compared to the results obtained for the Yukawa potential, which does not take the ion core into account. Increasing the steepness of the core edge or decreasing the depth of the minimum leads to more pronounced screening due to bound electrons. Full article
Show Figures

Figure 1

16 pages, 1608 KiB  
Article
Control-Oriented Free-Boundary Equilibrium Solver for Tokamaks
by Xiao Song, Brian Leard, Zibo Wang, Sai Tej Paruchuri, Tariq Rafiq and Eugenio Schuster
Plasma 2024, 7(4), 842-857; https://doi.org/10.3390/plasma7040045 - 23 Oct 2024
Viewed by 413
Abstract
A free-boundary equilibrium solver for an axisymmetric tokamak geometry was developed based on the finite difference method and Picard iteration in a rectangular computational area. The solver can run either in forward mode, where external coil currents are prescribed until the converged magnetic [...] Read more.
A free-boundary equilibrium solver for an axisymmetric tokamak geometry was developed based on the finite difference method and Picard iteration in a rectangular computational area. The solver can run either in forward mode, where external coil currents are prescribed until the converged magnetic flux function ψ(R,Z) map is achieved, or in inverse mode, where the desired plasma boundary, with or without an X-point, is prescribed to determine the required coil currents. The equilibrium solutions are made consistent with prescribed plasma parameters, such as the total plasma current, poloidal beta, or safety factor at a specified flux surface. To verify the mathematical correctness and accuracy of the solver, the solution obtained using this numerical solver was compared with that from an analytic fixed-boundary equilibrium solver based on the EAST geometry. Additionally, the proposed solver was benchmarked against another numerical solver based on the finite-element and Newton-iteration methods in a triangular-based mesh. Finally, the proposed solver was compared with equilibrium reconstruction results in DIII-D experiments. Full article
(This article belongs to the Special Issue New Insights into Plasma Theory, Modeling and Predictive Simulations)
Show Figures

Figure 1

16 pages, 3663 KiB  
Article
Energy Efficiency of Plasma Jets: Electrical Modeling Based on Experimental Results
by Achraf Hani, Karim Saber, Alyen Abahazem and Nofel Merbahi
Plasma 2024, 7(4), 826-841; https://doi.org/10.3390/plasma7040044 - 23 Oct 2024
Viewed by 421
Abstract
This paper focuses on the determination of and improvement in the energy efficiency of plasma jets. To achieve this goal, an equivalent electrical model of a discharge reactor was developed, incorporating variable electrical parameters. The evolution of these parameters was determined by a [...] Read more.
This paper focuses on the determination of and improvement in the energy efficiency of plasma jets. To achieve this goal, an equivalent electrical model of a discharge reactor was developed, incorporating variable electrical parameters. The evolution of these parameters was determined by a mathematical identification method based on the recursive least squares algorithm (RLSA). The good agreement between the measured currents and those calculated using our electrical circuit, as well as the significant shapes of the estimated parameters, confirmed the accuracy of the parameter estimation method. This allowed us to use these parameters to determine the energy delivered to the reactor and that used during the discharge. This made our reactor controllable at the energy level. Thus, the ratio between these two energies allowed us to calculate the energy efficiency of plasma jets at each discharge instant. We also studied the effect of the applied voltage on efficiency. We found that efficiency was increased from 75% to 90% by increasing the voltage from 6 kV to 8 kV. All the results found in this work were interpreted and compared with the discharge behavior. This proposed model will help us to choose the right operating conditions to reach the maximum efficiency. Full article
(This article belongs to the Special Issue New Insights into Plasma Theory, Modeling and Predictive Simulations)
Show Figures

Figure 1

10 pages, 5511 KiB  
Article
Polishing Ceramic Samples with Fast Argon Atoms at Different Angles of Their Incidence on the Sample Surface
by Sergey N. Grigoriev, Alexander S. Metel, Marina A. Volosova, Enver S. Mustafaev and Yury A. Melnik
Plasma 2024, 7(4), 816-825; https://doi.org/10.3390/plasma7040043 - 17 Oct 2024
Viewed by 449
Abstract
Mechanical polishing of a product makes it possible to decrease the roughness of its surface to Ra = 0.001 µm by rubbing it with a fine abrasive contained in a fabric or other soft material. This method takes too much time and is [...] Read more.
Mechanical polishing of a product makes it possible to decrease the roughness of its surface to Ra = 0.001 µm by rubbing it with a fine abrasive contained in a fabric or other soft material. This method takes too much time and is associated with abrasive particles and microscopic scratches remaining after the processing. As such, a non-contact treatment with plasma and accelerated particles has been chosen in the present work to study polishing of ceramic samples. The small angular divergence of fast argon atoms made it possible to obtain the dependence of the sample roughness on the angle α of the atom’s incidence on its surface. It was found that the roughness weakly depends on the angle α, if not exceeding the threshold value αo ~ 50°, and rapidly decreases with increasing α > αo. Polishing with fast argon atoms leads to a noticeable decrease in friction of ceramic samples. Full article
Show Figures

Figure 1

23 pages, 43715 KiB  
Review
Formation of Fine Structures in Incompressible Hall Magnetohydrodynamic Turbulence Simulations
by Hideaki Miura
Plasma 2024, 7(4), 793-815; https://doi.org/10.3390/plasma7040042 - 11 Oct 2024
Viewed by 454
Abstract
Hall magnetohydrodynamic simulations are often carried out to study the subjects of instabilities and turbulence of space and nuclear fusion plasmas in which sub-ion-scale effects are important. Hall effects on a structure formation at a small scale in homogeneous and isotropic turbulence are [...] Read more.
Hall magnetohydrodynamic simulations are often carried out to study the subjects of instabilities and turbulence of space and nuclear fusion plasmas in which sub-ion-scale effects are important. Hall effects on a structure formation at a small scale in homogeneous and isotropic turbulence are reviewed together with a simple comparison to a (non-Hall) MHD turbulence simulation. A comparison between MHD and Hall MHD simulations highlights a fine structure in Hall MHD turbulence. This enhancement of the fine structures by the Hall term can be understood in relation to the whistler waves at the sub-ion scale. The generation and enhancement of fine-scale sheet, filamentary, or tubular structures do not necessarily contradict one another. Full article
Show Figures

Figure 1

Previous Issue
Back to TopTop