Plasma Parameters Research Articles

A spectral bias-error stepwise correction method of plasma image-spectrum fusion based on deep learning for improving the performance of LIBS

Poor spectral stability seriously hinders the wide application of laser-induced breakdown spectroscopy (LIBS), so how to improve its stability is the focus, hotspot, and difficulty of current research. In this study, to achieve high precision quantitative analysis under complex detection conditions, utilizing the fusion of multi-dimensional plasma information and the integration of physical models and algorithmic models, a spectral bias-error stepwise correction method of plasma image-spectrum fusion based on deep learning (SBESC-PISF) was proposed. In this method, based on the statistical properties of LIBS spectra, the actual obtained spectra were decomposed into three parts: the ideal spectral intensity related only to the element concentration, and the spectral bias and spectral error caused by the fluctuation of complex high-dimensional plasma parameters. Further, the deep learning methods were used to fully excavate all the effective features in the plasma images and spectra to invert the complex high-dimensional plasma parameters according to the physical models. Finally, the estimation models of spectral bias and spectral error were established based on these features, to realize the high-precision correction of spectral intensity. To verify the feasibility of SBESC-PISF, the spectra of aluminum alloy samples obtained under three complex detection conditions were used for analysis. Under the experimental condition of laser energy fluctuation, after correction by SBESC-PISF, R2 of the three calibration curves was all increased to 0.999, RMSE and STD of the validation set (RMSEV, STDV) were reduced by 55.246 % and 50.167 %, respectively. Under the experimental condition of defocusing amount fluctuation, R2 was also all increased to 0.999, RMSEV and STDV were decreased by 58.201 % and 51.006 %, respectively. When the laser energy and defocusing amount fluctuate simultaneously, R2 was increased to 0.999, 0.996 and 0.988, RMSEV and STDV were reduced by 58.776 % and 54.397 %, respectively. These experimental results demonstrate that the spectral fluctuation correction of SBESC-PISF under complex detection conditions is effective and has wide applicability.

Real-time measurement of electron temperature using a coupled centre-tapped emissive probe and a Langmuir probe (CCTELP)

Abstract Conventional electrostatic probes are commonly used for measuring the plasma parameters like plasma density, electron temperature, plasma potential and floating potential respectively in a laboratory plasma to unveil physical processes of relevance to magnetosphere and fusion plasmas. With such probes, real-time measurement of electron temperature and its fluctuating AC component becomes very difficult. These measurements are significant as they directly give the measure of energy flux and hence can be utilized in estimating the turbulence-induced energy loss in any plasma system, especially useful for electron temperature gradient plasmas. Although Triple Langmuir Probe (TLP) diagnostics provide information on real-time measurement of electron temperature, this involves many complications. These complications of TLP are suitably overcome by the proposed diagnostic, which makes use of a combination of a closely separated centre tap emissive probe (CTEP) and Langmuir probe (LP) installed on a single probe head. The coupled centre-tapped emissive and Langmuir probe (CCTELP) provides direct measurement of electron temperature (T_e) and its fluctuations (T ̃_e). The design of the proposed diagnostic is very simple and it is almost free of rigorous control electronics and post-data analysis otherwise needed to estimate the electron temperature. These features make this diagnostic an additional and simple candidate for real-time measurement of electron temperature and its fluctuation. The paper will highlight details on this novel diagnostics, called CCTELP for the measurement in Maxwellian plasmas.

Exploring the dynamics of the heavy magnetized dusty plasma in laboratory experiments and solar wind interaction with lunar terminator: Theoretical predictions into the role of polarization force

This study is motivated by the lack of research that connects the dynamics of space dusty plasma (DP) with the existing experimental findings and the role of the magnetic field in the case of massive DP. For that purpose, we presented a theoretical interpretation of the dynamics of strongly (experimental) and weakly (space) magnetized DP, including the influence of the polarization force (PF). We used the multifluid model to describe the dynamics of dust particles while the hot plasma of electrons and ions is described by the Boltzmann distribution. We derived the dispersion relation to investigate the behavior of the compressive dust-acoustic waves (DAWs). To get a full picture of the mechanism of dust particles, we used the reductive perturbation technique to obtain the periodic solution for the Zakharov–Kuznetsov equation (ZK), which is coincidental with the observed wave profiles. In the case of the experimental application, we observed that the non-propagating instability starts at a small value of the polarization parameter (R), which is 0.02. Therefore, for values of R less than 0.02, the linear analysis revealed that increasing the value of the polarization parameter is not significant in distinguishing the growth rates. Moreover, we noted that both R and the applied magnetic field enhance the strength of the wave electric field. Interestingly, calculating the value of the electric field required to levitate the dust particles that are subject to a high magnetic field agrees with our theoretical findings. The current model has also been applied to DP observed in the lunar terminator. Our results reveal no role for the PF in the lunar terminator. The analysis conducted using the New Hampshire Dispersion Relation Solver (NHDS) confirms the dominance of electrostatic modes in response to the solar wind interaction with the lunar terminator. Moreover, at certain values of plasma parameters such as the temperature of solar wind electrons and ions and the density of dust particles and solar wind electrons, there is a cutoff in the fluid dispersion curve corresponding to certain values of the normalized wavenumber. Such electrostatic profiles could contribute to the observed glow in the horizontal direction of the lunar terminator.

Investigation of the behaviours of cathode spot current density on plasma parameters in low-current vacuum arc

Investigation of the behaviours of cathode spot current density on plasma parameters in low-current vacuum arc

Analysis of the Thermal Conductivity Mechanism Affecting on the Plasma Parameters in Instability Low Current Vacuum Arc

Analysis of the Thermal Conductivity Mechanism Affecting on the Plasma Parameters in Instability Low Current Vacuum Arc

Aspects of thermal utilization of organic poultry waste

Relevance. Currently, poultry farming, as part of the agro-industrial complex, is showing strong growth, which leads to an increase in the generation of organic waste. Chicken manure is a problematic organic waste from poultry farming in terms of its quantity, environmental hazard and moisture content. On the other hand, chicken manure is a potential renewable source of phosphorus. The use of chicken manure as a technogenic deposit of phosphorus will improve the level of environmental and food security. Aim. Research of influence of parameters of plasma and pyrolysis treatment of chicken manure on waste weight loss and phosphorus content in biochar. Methods. Experimental studies of the treatment of chicken manure with microwave plasma and induction pyrolysis; determination of the mass fraction of moisture during drying and loss of waste mass during disposal by the gravimetric method; determination of phosphorus in biochar using the Denizhe colorimetric method modified by A. Malyugin and S. Khrenova. Results and conclusions. The author has carried out the experimental studies on the treatment of chicken manure with microwave plasma and induction pyrolysis. It was shown that effective ways to reduce the mass of chicken manure and prevent environmental pollution are the treatment of manure with microwave plasma and its induction pyrolysis. It was established that when chicken manure is processed in microwave plasma in an inert environment at temperatures up to 1560°C, the mass of waste is reduced by 92.76% with an exposure duration of 7 minutes. At the same time, the content of P2O5 in biochar is up to 52.2 g/100 g of biochar. Further exposure to plasma leads to vitrification of the waste. As the time of treatment of chicken manure with microwave plasma increases, the loss of waste mass grows exponentially. Induction pyrolysis of chicken manure in an inert environment at a temperature of 1000°C makes it possible to reduce the mass of waste by 92.30%. P2O5 content in biochar grows with increasing pyrolysis temperature and amounts to 12.64 g/100 g of biochar. Biochar obtained by treating chicken manure with microwave plasma and induction pyrolysis can be considered as a source of phosphorus. The results obtained indicate the possibility of utilizing chicken manure using microwave plasma and induction pyrolysis.

Alpha B-crystallin Ameliorates Imbalance of Redox Homeostasis, Inflammation and Apoptosis in an Acute Lung Injury Model with Rats.

Ischemia-reperfusion (IR) of the aorta is a significant contributor to the development of postoperative acute lung damage after abdominal aortic surgery. The aim of the present study was to examine the effect of alpha B-crystallin, a small heat shock protein (known as HspB5), on lung injury induced by abdominal aortic IR in rats. Male Sprague-Dawley rats were divided into three groups: control, ischemia-reperfusion (IR, 90 min ischemia and 180 min reperfusion), and alpha B-crystallin +IR. Alpha B-crystallin (50 μg/100 g) was intraperitoneally administered 1 h before IR. Lung tissue samples were obtained for histological and biochemical analyses of oxidative stress and cytokine and apoptosis parameters in plasma, lung tissues, and bronchoalveolar lavage (BAL) fluid. The levels of malondialdehyde, reactive oxygen species, total oxidant status, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), nuclear factor kappa B (NFKβ), caspase-9 (CASP-9), 8-hydroxy-2'-deoxyguanosine, total antioxidant status, superoxide dismutase, and interleukin-10 levels in lung tissues, plasma, and BAL fluid (p<0.05 versus control) increased in Aortic IR. However, alpha B-crystallin significantly reduced the lung tissue levels of oxidative, inflamatuvar, and apoptotic parameters in the plasma, lung tissues, and BAL fluid (p<0.05 versus aortic IR). Histopathological results showed that alpha B-crystallin ameliorated the morphological changes related to lung injury (p<0.001). Alpha B-crystallin substantially restored disrupted the redox balance, inflammation, and apoptotic parameters in rats exposed to IR. The cytoprotective effect of alpha B-crystallin on redox balance might be attributed to improved lung injury.

Ion temperature gradient modes modulational stability with kappa-distribution

We investigated the modulational stability and instability of the ion temperature gradient (ITG) mode in electron-ion plasma. Ions are dynamic species, whereas electrons follow a Kappa distribution. We used the reduction perturbation approach to determine the linear dispersion relation for the fluid under consideration. The nonlinear Schrodinger equation describes nonlinear features such as nonlinear modulational stability or instability in the ITG mode. The product of dissipation and nonlinear coefficients, known as LM, contains both modulational stability and instability in the ion temperature gradient mode. Theoretical results are expanded numerically, showing the influence of various plasma parameters on modulational stability and instability, particularly the superthermality coefficient κ e . The current observations may be extended to space and laboratory plasma for modification.

Plasma impact on black hole shadow and gravitational weak lensing in Einstein-Maxwell-scalar theory

Abstract In this paper, we investigate the optical properties of a non-rotating charged black hole (BH) in the Einstein-Maxwell-scalar (EMS) theory, together with a plasma medium. We first consider the photon sphere and shadow radius under the impact of the plasma medium existing in the environment surrounding the BH in EMS theory. We show that the radius of the photon sphere and the BH shadow decrease under the influence of the parameter $\beta$. We further study the gravitational weak lensing in detail by adapting general methods and derive the light ray's deflection angle around the BH together with the plasma environment. It is found that for uniform plasma, the deflection angle increases with the rise of the plasma parameter, whereas it decreases with the increase of the plasma parameter for non-uniform plasma. Besides, we also study the magnification of image brightness.

Exact stark analytical function for Hα line based on the FFM model related with plasma parameters

Optical Emission Spectroscopy is a widely used technique for plasma diagnosis, with particular interest in hydrogen atomic emission due to its prevalence in plasmas. However, accurately determining plasma parameters like electron density, electron temperature, and gas temperature starting from the experimental profiles remains a challenge. This paper introduces a comprehensive model for Stark broadening of the Hα line in a wide range of plasma conditions, addressing the limitations of existing analytical expressions for line shapes. The proposed model encompasses the full splitting of the transition into fifteen Lorentzian profiles and electric micro-field fluctuations surrounding the emitting atoms due to collisions with charged particles. Starting from accurate spectral data obtained from realistic computer simulations, fitting parameters of the model, have been obtained by using an optimization method based on a genetic algorithm. The set of parameters of the model are reported for a wide range of plasma conditions. The behavior of these parameters is analyzed to understand their dependence in terms of the electron density and temperature and gas density of the plasma. The model parameters here obtained constitute a useful tool in plasma diagnosis to obtaining the values of the physical parameters of the plasma starting from the experimental profiles.

Non-lethal biomarkers as promising tools for fish health assessment: In situ exposure to bifenthrin as a case study

Non-lethal biomonitoring should provide an innovative approach to establish bioethical protocols for the management of both aquaculture and wild fisheries resources. We aimed to assess non-lethal biomarkers in Piaractus mesopotamicus caged in a rice field during a bifenthrin (BF) application. We analyzed parameters related to the immune system, energy metabolism and oxidative stress in fish skin mucus and blood plasma. Fish exposed to BF showed a significant increase in skin mucus glucose levels and the enzymatic activities of protease, alkaline phosphatase and superoxide dismutase. Regarding plasmatic parameters, BF increased the levels of glucose, total protein and albumin, but decreased triglycerides. In addition, increased activities of lysozyme and alkaline phosphatase were found in the blood plasma of exposed fish. Our results indicated an increased energy demand, altered immune function and a mild oxidative stress response in fish exposed in situ to BF. We have shown that skin mucus and blood plasma are very promising matrices for the development of non-lethal biomarkers to assess fish health in a stressed environment.

Microwave Plasma Pencil for Surface Treatment: Numerical Study of Electromagnetic Radiation and Experimental Verification.

An atmospheric pressure plasma source of the microwave plasma pencil type utilizing a coaxial line is presented. The generated plasma takes the form of a cylinder up to about 30 mm long and up to 5 mm in diameter. It is suitable for surface sterilization, surface treatment, and material processing. This study numerically analyzes the electromagnetic radiation emitted by the plasma pencil, which compromises performance and poses safety risks. Electric field distributions, radiation patterns, the ratio of the power entering the discharge to the incident wave power, and the ratio of radiated power to entering power were numerically investigated for different plasma parameters and pencil lengths. Results indicate that increasing electron density, gas temperature, plasma length, and pencil length increases the radiated power by up to more than 60% of the entering power, and the radiation patterns can be highly non-uniform with strong backward lobe. The numerical finding were qualitatively confirmed experimentally. It was also found that it is possible to reduce radiation from the device by using appropriately designed cones, the presence of which does not impede its performance.

Quantification of locked mode instability triggered by a change in confinement

Abstract This work presents the first analysis of the disruptive locked mode (LM) triggered by the dynamics of a confinement change. It shows that, under certain conditions, the LM threshold during the transient is significantly lower than expected from steady states. We investigate the sensitivity to a controlled n = 1 error field (EF) activated prior to the L-H transition in the COMPASS tokamak, at q 95 ∼ 3, β N ∼ 1, and using EF coils on the high-field side of the vessel. A threshold for EF penetration subsequent to the L-H transition is identified, which shows no significant trend with density or applied torque, and is an apparent consequence of the reduced intrinsic rotation of the 2/1 mode during this transient phase. This finding challenges the assumption made in theoretical and empirical works that natural mode rotation can be predicted by global plasma parameters and urges against using any parametric EF penetration scaling derived from steady-state experiments to define the EF correction strategy in the entire discharge. Furthermore, even at EFs below the identified penetration threshold, disruptive locking of sawtooth-seeded 2/1 tearing modes is observed after about 30% of L-H transitions without external torque.

First spectroscopic studies in the plasma-beam installation

This paper presents the results of spectroscopic measurements of plasma in a linear simulator of a plasma-beam installation (PBI) for conducting materials science research. For the first time, non-contact optical diagnostic methods were employed to measure the plasma parameters in the PBI. These measurements were allowed for the clarification of the PBI plasma parameters and the identification of transition zones in different operational modes. Analysis of the plasma emission spectrum enabled the identification of impurity spectral lines and the estimation of key plasma parameters under varying experimental conditions. The spectra were recorded using two optical spectrometers covering a wavelength range of 200–800 nm. The experimental conditions varied in terms of electron beam accelerating voltage (1–5 kV), working gas pressure (1–6 mTorr), and target bias voltage (from −500 to −100 V). The Boltzmann plot method and Stark broadening of the Balmer lines were used to estimate electron temperature and density. Based on the obtained spectroscopic data, the electron density and the electron temperature were determined. The methods described in this study are applicable to linear plasma devices.

Magnetosonic Waves Excited by Maxwellian Ring Protons in Space Plasma Environment

A comprehensive theoretical model for a homogeneous plasma system of hot, tenuous Maxwellian ring-distributed protons and the cold background of Maxwellian ions and electrons is used to study the resonant instabilities of magnetosonic (MS) waves. The perpendicular velocity integrals associated with the Maxwellian ring distribution have no analytical solution, hence, are solved numerically, while the parallel velocity integrals are solved analytically by invoking series expansion of the plasma dispersion function. For the plasma parameters relevant to Earth’s inner magnetosphere, the theoretical model generates MS waves with frequencies from 5 times the local proton cyclotron frequency to above the lower hybrid frequency for a propagation angle of 89.5°. Hydrogen (H+) band electromagnetic ion cyclotron waves are also excited by the Maxwellian ring protons for the same set of plasma parameters. A detailed analysis reveals that a sufficiently large ring velocity, as well as a smaller perpendicular and parallel thermal velocity, can enhance the MS wave growth. The study also explores the role of background plasma parameters in modulating the waves. The present theoretical model reproduces the harmonics of the MS waves observed by the Van Allen Probes in the Earth’s inner magnetosphere. Further, the model can generate MS waves in other plasma environments, e.g., Mars, where the presence of ring protons has been established by MAVEN in connection with the MS wave observations.

The Effect of Different Forms of Solid Feed on Biochemical Parameters in Blood Plasma of Calves

Abstract The study examined how different solid feeds affected the biochemical parameters in calf plasma. The experiment involved a control group and three test groups of calves, each fed with a different starter mixture. The results showed significant differences in some biochemical parameters between the feeding groups. Calves in groups P1 and P3 had a statistically higher glucose concentration in blood plasma compared to group C. Calves from group P3 had a higher concentration of urea in blood plasma than calves from group C. Calves in groups P1 and P3 also had higher concentrations of total protein and globulin in blood plasma compared to group C. The concentration of inorganic phosphate in the blood plasma of calves from group P3 was significantly higher than that of group C. Female calves in the experimental groups showed a lower concentration of NEFA at three months of age compared to the control group. It was concluded that feeding calves with a starter mixture containing whey and easily digestible protein had a positive effect on the nutritional status and energy balance of the calves.

Abstract P199: Renal kallikrein-1 is not essential in adaptation to an overnight potassium load

Background: Kallikrein-1 is a serine protease expressed in multiple tissues including the kidney, where it is secreted into the urine. Low urinary kallikrein levels are associated with essential hypertension, whereas high levels are associated with primary hyperaldosteronism in humans. Global kallikrein-1 deletion in mice has been shown to lead to hyperkalemia in response to an acute potassium load as well as defective cleavage of gamma-ENaC, suggesting a direct role in distal K + handling. However, it remains unclear whether effects seen with global kallikrein-1 loss are secondary to loss of extrarenal or renal kallikrein, which is primarily expressed in the connecting tubule. Methods: To test the hypothesis that renal kallikrein-1 is necessary for increased K + secretion in response to acute dietary K + load, we generated mice with conditional knockout of kallikrein-1 in the distal tubule (Klk1 flox - Calbindin-Cre, KS-Klk1 KO). Mice were treated with a K + deficient diet (0% K + , LK) for 9.5 days and then placed in metabolic cages for 12hr overnight collection of urine on control (LK) or high K + (5%, OHK) diets. Metabolic parameters in plasma were measured using iSTAT and kidneys were harvested for downstream western blotting. Results: Deletion of kallikrein-1 in KS-Klk1 kidney was confirmed by western blotting and urine kallikrein activity assay. On LK diet, both WT and KS-Klk1 KO mice developed marked hypokalemia (WT 2.83+/-0.23 vs KO 2.88+/-0.15 meq/dL). Following OHK challenge, hyperkalemia developed to similar levels in both groups (WT 7.13+/-0.56 vs KO 7.74+/-0.35). However, KS-Klk1 KO mice with HK challenge exhibited a more pronounced drop in serum [Na + ] compared with WT (WT 142.6+/-1.4 vs KO 136.6+/-1.3, p=0.022) and correspondingly lower serum [Cl - ] (WT 119.0+/-0.62 vs KO 115.9+/-0.96). Gamma-ENaC quantitation by western blot revealed similar ratios of cleaved: uncleaved species between genotypes. No significant changes between genotypes were detected in urine volume or urine Na+/K+ ratios. Conclusions: KS-Klk1 KO mice do not display defective K+ handling or ENaC processing in response to an acute 12 hr overnight high K + diet. However, they do display relative hyponatremia compared with WT. These data may suggest compensatory mechanisms for potassium transport or a direct a role for renal kallikrein-1 in regulation of renal water transport.

Effect of polarization on spectroscopic characterization of laser produced aluminium plasma

Laser-induced breakdown spectroscopy (LIBS) is a well-established technique widely used in fundamental research and diverse practical fields. Polarization-resolved LIBS, a variant of this technique, aims to improve the sensitivity, which is a critical aspect in numerous scientific domains. In our recent work we demonstrated that the degree of polarization (DOP) in the emission depends on the spatial location and time in a nano second laser generated aluminium plasma1. Present study investigates the effect of polarized emission on the estimation of plasma parameters. The plasma parameters are estimated using the conventional spectroscopic methods such as Boltzmann plot and line intensity ratio for the estimation of electron temperature and Stark broadening for estimating the electron density. The estimated plasma temperature using Boltzmann plot method shows large errors in electron temperature for the locations where DOP is higher. However, the electron density estimated using the Stark width does not show such variation. The observed ambiguity in temperature estimation using the Boltzmann plot method appears to be a consequence of deviation from expected Maxwell Boltzmann distribution of population of the involved energy levels. These findings highlight the need of assessing the DOP of the plasma before selecting the polarization for PRLIBS or temperature estimation using Boltzmann plots in elemental analysis.

Resolving studies of Balmer alpha lines relevant to the LIBS analysis of hydrogen isotope retention

Utilizing Laser-Induced Breakdown Spectroscopy (LIBS) for detecting deuterium and tritium retention in fusion devices poses a significant challenge due to the experimental limitations in resolving hydrogen isotope Balmer alpha lines (Hα, Dα, and Tα). This study utilizes the Rayleigh criterion to distinguish Tα and Dα lines by determining the maximum line widths and corresponding plasma parameters. Experimental validation was performed through LIBS analysis of heavy water-doped graphite/silica gel targets in both argon and helium atmospheres to assess the predicted plasma parameters and line profile shapes. The optimization of laser pulse energy, gas pressure, delay, and gate times aimed at achieving fully resolved lines based on the intensity, width, and the dip between deuterium and hydrogen Balmer alpha lines. By fine-tuning these experimental parameters, the study successfully achieved a dip of less than 10 % between the Hα and Dα lines with a satisfactory signal-to-noise ratio, demonstrating the feasibility of fully resolving the Tα and Dα lines. These findings underscore the potential of LIBS in enhancing the detection of deuterium and tritium retention in fusion devices.

Soliton interaction in a two-temperature electron plasma with trapping and superthermality effects

Head-on collision of the two small-amplitude electron-acoustic (EA) solitons is studied in an unmagnetized collisionless plasma in the presence of superthermal (hot) trapped electrons. For this purpose, using a well-known extended Poincare–Lighthill–Kuo (PLK) method, a pair of the trapped Korteweg–de Vries (tKdV) equations is derived to investigate the soliton trajectories and phase shifts. The latter are found dependent on amplitudes of the interacting solitons, effectively altering with hot-electron superthermality and plasma parameters. Typical parameters for the electron diffusion region (EDR) and day-side auroral zone have been selected to examine the impact of hot-electron superthermality, trapping parameter, hot-to-cold electron number density ratio, and cold-to-hot electron temperature ratio on the profiles of potential excitations and phase shifts of interacting solitons. It is found that phase speed of the EA waves becomes altered by varying the κ–parameter, strongly modifying the nonlinearity and dispersive coefficients in a superthermal trapped plasma. However, particle trapping phenomenon does not affect the linear phase speed but introduces a fractional nonlinearity in the tKdV equations of two interacting solitons. The impact of the adiabatic and isothermal pressures is also highlighted to show new modifications in the propagation characteristics of two interacting solitons.