scholarly journals Population Kinetics Modeling of Low-Temperature Argon Plasma

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 100
Author(s):  
Hyun-Kyung Chung ◽  
Mi-Young Song ◽  
Ji-Won Kwon ◽  
Myeong-Geon Lee ◽  
Jihoon Park ◽  
...  
Keyword(s):  
Low Temperature ◽  
Plasma Diagnostics ◽  
Argon Plasma ◽  
Optical Emission ◽  
Plasma Radiation ◽  
Temperature Plasma ◽  
Single Temperature ◽  
Collisional Radiative Model ◽  
Radiative Model ◽  
Measured Line

Optical emission spectroscopy has been widely used in low-temperature argon plasma diagnostics. A coronal model is usually used to analyze the measured line ratios for diagnostics with a single temperature and density. However, many plasma processing conditions deviate from single temperature and density, optically thin conditions, or even coronal plasma conditions due to cascades from high-lying states. In this paper, we present a collisional-radiative model to investigate the validity of coronal approximations over a range of plasma conditions of Te = 1–4 eV and Ne = 108–1013 cm−3. The commonly used line ratios are found to change from a coronal limit where they are independent of Ne to a collisional-radiative regime where they are not. The effects of multiple-temperature plasma, radiation trapping, wall neutralization, and quenching on the line ratios are investigated to identify the plasma conditions under which these effects are significant. This study demonstrates the importance of the completeness of atomic datasets in applying a collisional-radiative model to low-temperature plasma diagnostics.

scholarly journals Assessment of quality and safety of pork treated with low-temperature atmospheric-pressure plasma

2021 ◽  
Vol 6 (1) ◽  
pp. 78-86
Author(s):  
N. Yu. Moskalenko ◽  
O. A. Kudryashova ◽  
L. S. Kudryashov ◽  
S. L. Tikhonov ◽  
N. V. Tikhonova ◽  
...  
Keyword(s):  
Low Temperature ◽  
Atmospheric Pressure ◽  
Cold Treatment ◽  
Meat Product ◽  
Argon Plasma ◽  
Atmospheric Pressure Plasma ◽  
Weight Fraction ◽  
Microbial Inactivation ◽  
Temperature Plasma ◽  
Pressure Plasma

It is known that processing methods ensuring partial or full microbial inactivation are quite limited. Therefore, it is of great interest to develop technique and technologies allowing the effective action on microorganisms without a significant influence on product properties. The use of cold plasma can be one of the promising methods of meat product treatment by cold sterilization. The present work examines a possibility of chilled meat treatment with low-temperature atmospheric-pressure plasma to increase its stability to microbial spoilage and extend shelf life. To obtain low temperature plasma, the equipment developed by the designing department “Plasmamed” was used. Chilled meat was treated with low-temperature atmospheric-pressure argon plasma for 5, 10, 20 and 30 min. Samples were stored at a temperature of 2–4 °C for 10 days. Organoleptic indices, moisture weight fraction, changes in pH and water activity were analyzed before treatment and during storage. Sanitary microbiological analyses were carried out by the following indicators: quantity of mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM), the presence and quantity of coliforms, Salmonella, Escherichia coli, Listeria monocytogenes, Proteus. It was shown that meat cold treatment with argon plasma inhibited the development of mesophilic microorganisms. The colony forming units detected in the samples after ten days of storage were determined by the duration of exposure to plasma. It was proved that meat treatment for 15 and 30 min had the bactericidal effect and facilitated an improvement in meat color during storage. The organoleptic indices of the samples treated with plasma corresponded to the requirements of standards and approved consumer characteristics.

scholarly journals Influence of Resonance Radiation Transport on Chemical Equilibrium in an Argon Arc

2019 ◽  
Vol 6 (2) ◽  
pp. 119-122
Author(s):  
S. Gortschakow ◽  
D. Kalanov ◽  
Yu. Golubovskii
Keyword(s):  
Chemical Equilibrium ◽  
Radiation Transport ◽  
Kinetic Scheme ◽  
Resonance Radiation ◽  
Arc Plasma ◽  
Temperature Plasma ◽  
Collisional Radiative Model ◽  
Transport Effects ◽  
Radiative Model ◽  
Two Temperature

<p class="Default">Deviations from chemical equilibrium in argon arc plasma are analysed by means of collisional-radiative model. Corresponding comprehensive kinetic scheme has been developed and applied form study of free-burning arc at the conditions typical for welding applications. While the natural lifetime have been used for radiation emitted from highly excited argon states, the resonance radiation was described taking into account the radiation transport effects. Resulting spatial distributions of excited argon atoms are compared for the cases of LTE and two-temperature plasma using different approaches for the description of the resonance radiation transport.<br /><br /></p>

Collisional radiative model for the evaluation of the Thermal Helium Beam diagnostic at ASDEX Upgrade

2022 ◽  
Author(s):  
Daniel Wendler ◽  
Ralph Dux ◽  
Rainer Fischer ◽  
Michael Griener ◽  
Elisabeth Wolfrum ◽  
...  
Keyword(s):  
Excited States ◽  
Ultra Violet ◽  
Plasma Edge ◽  
Excitation Mechanism ◽  
Computationally Efficient ◽  
Injection Point ◽  
Collisional Radiative Model ◽  
Radiative Model ◽  
Measured Line ◽  
Vacuum Ultra Violet

Abstract The thermal helium beam diagnostic at ASDEX Upgrade is used to infer the electron density ne and temperature Te in the scrape-off layer and the pedestal region from the emission of visible lines of the locally injected helium. The link between ne and Te and the emission is provided by a collisional radiative model, which delivers the evolution of the populations of the relevant excited states as the He atoms travel through the plasma. A computationally efficient method with just three effective states is shown to provide a good approximation of the population dynamics. It removes an artificial rise of Te at the plasma edge when using a simple static model. Furthermore, the re-absorption of the vacuum ultra-violet resonance lines has been introduced as additional excitation mechanism being mainly important in the region close to the injection point. This extra excitation leads to a much better fit of the measured line ratios in this region for larger puff rates.

scholarly journals Theoretical Modeling of High-Resolution X-ray Spectra Emitted by Tungsten and Molybdenum Ions from Tokamak Plasmas

2020 ◽  
Vol 39 (5) ◽  
pp. 194-201
Author(s):  
Ł. Syrocki ◽  
K. Słabkowska ◽  
E. Węder ◽  
M. Polasik ◽  
J. Rzadkiewicz
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
Detailed Analysis ◽  
Electron Density ◽  
Wavelength Range ◽  
Tokamak Plasmas ◽  
Temperature Plasma ◽  
X Ray ◽  
Collisional Radiative Model ◽  
Radiative Model

AbstractIn order to allow the advanced interpretation of the X-ray spectra registered by the high-resolution crystal KX1 spectrometer on the JET with an ITER-like wall, especially to determine how the relative emission contributions of tungsten and molybdenum ions change during a JET discharge, the X-ray spectra have been carefully modeled over a narrow wavelength range. The simulations have been done in the framework of Collisional–Radiative model implemented in Flexible Atomic Code for an electron density (ne = 2.5 × 1019 m−3), and electron temperatures between Te = 3.0 keV and Te = 4.5 keV, typical for JET. Moreover, performed detailed analysis in the framework of the proposed procedure can be useful in determining temperature of a high temperature plasma generated in tokamaks.

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