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This study presents a source for studying thin‐film deposition utilizing vacuum UV (VUV) radiation from a remote argon or helium atmospheric plasma to initiate photochemistry in the precursor gas. We aim to assess how this radiation affects the deposition process and film structure while avoiding deposition inside the plasma source or particle formation. Deposition occurs where radiation interacts with the precursor and the growing film, as well as further downstream. The measured film properties clearly show that photon interaction with the film has a significant effect. Using hexamethyldisiloxane (HMDSO) as a precursor, we achieved nearly carbon‐free silicon dioxide (SiO2 ) film growth due to photodesorption of hydrocarbons from the growing film, as confirmed by infrared spectra and positive ion mass spectrometry. [ABSTRACT FROM AUTHOR]

The microwave-to-plasma energy conversion efficiency and the ease of plasma self-ignition are critical factors affecting the applications for microwave plasma sources (MPSs). This study presents a novel MPS utilizing dielectric wedges for self-ignition and improved energy conversion. Firstly, we crafted a dielectric wedge with a gradient refractive index, guiding the electric field from air to dielectric materials and facilitating microwave propagation along the dielectric in a waveguide. Through electromagnetic simulation, we explored how the size and permittivity of the dielectric wedge affect the electric field distribution. Then, the MPS based on the dielectric wedge was designed. In this configuration, a dielectric tube encloses the discharge tube, connecting to dielectric wedges to guide electromagnetic waves to the plasma. We analyzed the MPS performance using the Drude model, evaluating microwave energy conversion efficiency across various electron densities and collision frequencies. The results were compared with a commonly used MPS based on a tapered waveguide, demonstrating the proposed MPS has wider applicability across different operation conditions. Finally, experiments under low pressures were conducted using various gases, showing an average energy conversion efficiency of approximately 40% higher than the tapered waveguide MPS. The experiments also indicate the proposed MPS has a greater capability of self-ignition at lower power levels. These findings highlight the efficacy of incorporating dielectric wedges to enhance MPS performance, making it conducive for broader industrial applications. [ABSTRACT FROM AUTHOR]

A hydrogen ionic plasma source has been developed that is with a low residual electron presence (<0.01) using an aluminum plasma grid for negative hydrogen ion production and a control grid for electron removal. The ionic plasma density increases when a positive-ion beam is superimposed on a hydrogen plasma and irradiated onto the Al plasma grid. Even though the ionic plasma is formed in a region with high-deflection magnetic flux density, a collapse phenomenon can occur downstream of the region under certain electrode voltage conditions, causing electrons to appear and forming an electron plasma. Under electrode voltage conditions that prevent the collapse, the nine ionic plasmas, each passing through extraction apertures with a diameter of 1.3 cm, are combined to form the ionic plasma with a diameter of approximately 6 cm and a density on the order of 10 9 cm−3. [ABSTRACT FROM AUTHOR]

New approaches are required in the agricultural sector to keep pace with the ever-growing demand for food in the context of climate change and resource deterioration and avoiding further negative impact on the environment. Nonthermal plasma is an environmentally-friendly technology which could make a difference in future agricultural production. This review intends to introduce the topic of plasma agriculture to a broad audience by describing in detail various plasma sources with potential for agricultural applications, as well as the effects of plasma exposure of seeds, both at the macroscopic scale, and concerning the intimate mechanisms occurring inside the plant. Examples meant to illustrate the plasma effect on seeds and plants have been selected among extensively investigated species, such as cereals and legumes, as well as among a few species that are less often reported in literature, such as medicinal plants and woody plants. Generally, the main effects for all types of seeds consist in increased germination, higher plant yield, seed decontamination, and sometimes higher tolerance to various stress factors. These effects are due to the physical and chemical plasma interaction with seeds followed by the response of cell mechanisms, which are addressed in detail in the paper. Finally, a few crucial aspects regarding the practical application of nonthermal plasma in agriculture are discussed to illustrate the challenges and perspective of such treatments. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the antimicrobial effect of direct cold atmospheric plasma (CAPP) treatment for pre-harvest application using four different crop species: Hordeum vulgare L. (barley), Triticum aestivum L. (wheat), Brassica napus L. (rapeseed) and Lupinus angustifolius L. (lupine). The model bacterium Bacillus atrophaeus served as a proxy for spore-forming plant pathogens on the seed surface. After semi-dry inoculation of spores onto the seeds, treatment with two different plasma sources, a volume-dielectric barrier discharge and a corona discharge, and different exposure times was carried out. Subsequently, recovery of viable spores from the seeds' surfaces was performed. Moreover, seed viability was determined based on maximum germination, as well as water contact angle as a measure for seed surface hydrophilicity. Direct CAPP treatment was efficient in reducing viable spores of B. atrophaeus with no significant differences between the plasma sources, reaching a mean inactivation of 1 log10 CFU/mL across all treatment times and crops species. Maximum germination of seeds was not negatively affected under any treatment condition. Seed hydrophilicity was increased for both plasma sources tested. Overall, this study provides valuable information on the efficiency of direct CAPP treatment of seeds with the purpose of seed hygienization with the premise of unaltered seed vitality and evaluates the potential application in comparison with previous investigated CAPP methods. [ABSTRACT FROM AUTHOR]

The social market economies of the Western world considered the provision of plasma derivatives produced from publicly owned blood services as a legitimate state commitment and, until the last decades of the 20th century, many of the relevant jurisdictions maintained state‐supported fractionation plants to convert publicly collected plasma into products for the public health system. This situation started to change in the 1990s, because of several converging factors, and currently, publicly owned/subsidized, not‐for‐profit fractionation activity has shrunk to a handful of players. However, the collection of plasma from publicly owned blood services has continued and recent developments have increased the interest of state authorities globally to increase the volume of plasma collected to increase the level of strategic independence in the supply of crucial plasma‐derived medicines from commercial market pressures, particularly the global for‐profit fractionation sector with its dominance of source plasma from paid donors in the United States. This paper reviews the development of the plasma industry and the evolution of the pressures on the supply of plasma, which has led to a situation of scarcity of key plasma‐derived medicinal products (PDMPs). [ABSTRACT FROM AUTHOR]

Interchange instability is known to drive fast radial transport of electrons and ions in Jupiter's inner and middle magnetosphere. In this study, we conduct a statistical survey to evaluate the properties of energetic particles and plasma waves during interchange events using Juno data from 2016 to 2023. We present representative examples of interchange events followed by a statistical analysis of the spatial distribution, duration and spatial extent. Our survey indicates that interchange instability is predominant at M‐shells from 6 to 26, peaking near 17 with an average duration of minutes and a corresponding M‐shell width of <∼0.05. During interchange events, the associated plasma waves, such as whistler‐mode, Z‐mode, and electron cyclotron harmonic waves exhibit a distinct preferential location. These findings provide valuable insights into particle transport and the source region of plasma waves in the Jovian magnetosphere, as well as in other magnetized planets within and beyond our solar system. Plain Language Summary: The radial transport of plasma around a magnetized planet is crucial for understanding the underlying magnetospheric dynamics. Jupiter's magnetospheric dynamics are primarily dominated by the rapid rotation and plasma source from Io. This rapid rotation drives the interchange instability, where hot, low‐density plasma is moved toward the inner magnetosphere. During this process, the inward moving flux tube builds up magnetic pressure, potentially leading to the trapping of particles alongside plasma waves. In this study, we present several typical examples of interchange events, and conduct a statistical analysis to explore their spatial distribution, duration and spatial extent, as well as the typical features of the associated plasma waves. This survey provides insights into mass transport, the source of these plasma waves in Jupiter's magnetosphere, with potential implications for other magnetized planets within and beyond our solar system. Key Points: Our statistical survey indicates that interchange events occur over L (or M)‐shells ∼6–26 at Jupiter with a peak occurrence rate at M ∼ 17During interchange events, various types of plasma waves are intensified, each exhibiting a distinct preferential locationThe duration and the corresponding spatial extent of interchange events are analyzed for multiple events [ABSTRACT FROM AUTHOR]

We present a combined 1D imaging and broadband spectroscopy tool for analyzing laser-produced plasma sources of extreme ultraviolet light using a tapered zone plate that is dispersion-matched to a transmission grating. Specifically, we follow up on prior work [Mostafa et al. Opt. Lett. 48, 4316 (2023)] to obtain the actual spectral and spatial resolution of the imaging spectrometer and compare it to the design values. The imaging spectrometer is shown to have a spectral resolution of 1.2 nm at 13.5 nm, close to its design value, by assessing spectra obtained from carbon laser-produced plasma in a 5–180 nm wavelength band. The spatial resolution was obtained by placing slits near the object plane and back-illuminating the slit with a tin laser-produced plasma and found to be 17(5) µm, somewhat larger than the design specifications but still well within design limits for use for diagnosing plasma. [ABSTRACT FROM AUTHOR]

Plasma-functionalized liquids (PFLs) are rich in chemical species, such as ozone, hydrogen peroxide, singlet oxygen, hydroxyl radical and nitrogen oxides, commonly referred to as reactive oxygen and nitrogen species (RONS). Therefore, manifold applications are being investigated for their use in medicine, agriculture, and the environment. Depending on the goal, a suitable plasma source concept for the generation of PFLs has to be determined because the plasma generation setup determines the composition of reactive species. This study investigates three PFL-generating plasma sources—two spark discharges and a flow dielectric barrier discharge (DBD) system—for their efficacy in eliminating microbial contaminants from tissue samples aiming to replace antibiotics in the rinsing process. The final goal is to use these tissues as a cell source for cell-based meat production in bioreactors and thereby completely avoid antibiotics. Initially, a physicochemical characterization was conducted to better understand the decontamination capabilities of PFLs and their potential impact on tissue viability. The results indicate that the flow DBD system demonstrated the highest antimicrobial efficacy due to its elevated reactive species output and the possibility of direct treatment of tissues while tissue integrity remained. Achieving a balance between effective large-scale decontamination and the biocompatibility of PFLs remains a critical challenge. [ABSTRACT FROM AUTHOR]

Pulse plasma ion sources have been shown to be capable of achieving high negative hydrogen ion densities ( n H − ) or currents. The fast cooling of the electrons and reduction in the electron density (n e) provide favorable plasma conditions to improve the H− production, with a high density ratio of negative hydrogen ions to electrons during the pulse-off period. The purpose of this research is to further improve the performance of volume-produced H− ion sources based on the pulse power modulation. In this study, a time-modulated negative hydrogen plasma sustained by 10 kHz pulse power at the typical gas pressure of 0.3 Pa was numerically investigated using a global model. The model is compared with measurements obtained in a pulsed radio frequency ion source and shows a reasonable agreement. A steplike low-high power strategy in the active glow period and a short-pulse low power in part of the afterglow period are employed to mitigate overshoot of the electron temperature (T e) in the initial stage of the pulse period and to optimize H− production in the afterglow, respectively. The model predicts that a small-magnitude, short-duration low power operation in the afterglow increases n H − and decreases n e from the onset of the low power until the beginning of the next high power pulse, due to a modest temporary increase in the T e (less than 2 eV). It facilitates dissociative electron attachments and thus H− formation. The reduction in the n e indicates that positive ions lost to the walls cannot be compensated by weak ionization. H− production with a low number of co-extracted electrons can be optimized by adjusting the magnitude and duration of the low power in the afterglow. [ABSTRACT FROM AUTHOR]

Spurred by global COVID‐19, work in recent years has demonstrated that various devices based on technology generating cold plasma are capable of reducing the infectivity of virus particles. There is great potential in this approach, which is, however, hampered by the ability of most cold plasma science laboratories to test for antiviral effects of their individual plasma sources in sophisticated mammalian cell test systems. To this end, we developed a quick, simple, and fast assay system based on bacteriophages and their ability to lyse bacterial hosts, which can be monitored in readily available microplate readers. We successfully demonstrated the principal ability of this approach using two types of plasma jets, different microplate readers, and two different bacteriophage strains. [ABSTRACT FROM AUTHOR]

This investigation reports the influence of Ti–C and Ti–W cathode composition on an industrial-scale dc vacuum arc plasma source. Further, we analyze the influence of plasma generation and plasma properties on the resulting cathode surface after the operation and on basic film properties. The results are compared with previous work focused on Ti–Al and Ti–Si compound cathodes. For all Ti–X compound cathodes (X = W, C, Al, and Si), a direct correlation between plasma ion energy/charge and the cohesive energy of the cathode was demonstrated, with a small number of exceptions to a limited set of specific cathode compositions. Hence, the "velocity rule" and effects from different electron temperatures were suggested to be important for gaining a more detailed understanding of plasma properties. A discrepancy was found between the cathode and plasma ion composition, though the difference was reduced in a corresponding comparison between the cathode and the deposited film composition. A significant contribution of a flux of neutrals and/or macroparticles to the final film composition was, therefore, suggested. The effect of the melting point of the cathode phase composition on the intensity of macroparticle generation and the smoothness of the cathode surface operation was also investigated. The presented results contribute to the fundamental understanding of vacuum arc plasma generation and transport and are of importance for further development and applicability of Ti-based coatings from arc deposition. [ABSTRACT FROM AUTHOR]

A discharge in the annular cavity of a Hall effect thruster is sustained by extracting electrons from a radiofrequency (rf) inductively coupled plasma source located downstream of the thruster structure, where a radial magnetic field of 0.1-0.15 T is applied to the thruster discharge cavity by permanent magnets. Argon gas is introduced into the cavity via an anode structure and the ejected gas passes through the rf plasma source powered by a 13.56 MHz and 200 W generator. After turning on the rf plasma, a dc voltage is applied between a cathode installed inside the rf source and the anode of the Hall effect thruster, creating the bright annular discharge in the cavity. Measured ion energy distribution functions contain the energetic ions having the maximum potential close to the anode potential, demonstrating the ion acceleration from the annular cavity and the neutralization by the electrons in the rf plasma source. [ABSTRACT FROM AUTHOR]

In this paper we investigate the influence of cold plasma as novel method on the external otitis treatment which is a frequent cause of earache. 24 infected external auditory canals in 24 rats were categorized in four experimental groups including control, plasma exposed, ciprofloxacin drug and mixed of plasma-ciprofloxacin groups. In plasma group, dielectric barrier discharge was employed as the source of cold plasma in 5 days. All rats were observed with otoscope daily and a scoring system was used to evaluate swelling and effusion of the ear canal. Number of colonies in microbiological culture were counted in each group during the first 5 days after treatment. For the multiple group comparisons of swelling and effusion measured in the external auditory canal, Kruskal–Wallis analysis was applied and one-way anova and Kruskal–Wallis analysis was used for the statistical analysis of the results of the cultures in different days. Also, Tukey and Mann–Whitney tests was applied for multiple comparisons. Our findings show that swelling and effusion were obviously reduced in plasma group compared to control group (P < 0.01). Number of colonies in control group was statistically different from those in drug, plasma, and mixed group on the second to fifth day (p < 0.001). According to the results cold plasma can be introduced as an impressive method for external otitis treatment. Moreover, when cold plasma joined to antibiotic method, it leads to a superior performance respecting plasma or antibiotic method alone. [ABSTRACT FROM AUTHOR]

This work presents a heuristic for the selection of a time delay based on optimizing the global maximum of mutual information in orthonormal coordinates for embedding a dynamical system. This criterion is demonstrated to be more robust compared to methods that utilize a local minimum, as the global maximum is guaranteed to exist in the proposed coordinate system for any dynamical system. By contrast, methods using local minima can be ill-posed as a local minimum can be difficult to identify in the presence of noise or may simply not exist. The performance of the global maximum and local minimum methods are compared in the context of causality detection using convergent cross mapping using both a noisy Lorenz system and experimental data from an oscillating plasma source. The proposed heuristic for time lag selection is shown to be more consistent in the presence of noise and closer to an optimal uniform time lag selection. [ABSTRACT FROM AUTHOR]

This study employs a fast camera with frame rates up to 900,000 fps to measure the transfer of energy across spatial scales in helicon source plasmas and during flux rope mergers and the measurement of azimuthal mode structures in helicon plasmas. By extracting pixel-scale dispersion relations and power spectral density (PSD) measurements, we measure the details of turbulent wave modes and energy distribution across a broad range of spatial scales within the plasma. We confirm the presence of drift waves in helicon plasmas, as well as the existence of strong dissipation regions in the PSD at electron skin depth scales for both helicon and flux rope merger experiments. This approach overcomes many limitations of conventional probes, providing high spatial and temporal resolution, without perturbing the plasma. [ABSTRACT FROM AUTHOR]

Laser-collisional induced fluorescence is used to study the plasma generated by a split-ring resonator discharge under an external cusp shaped magnetic field created by permanent magnets. The electron density and electron temperature are measured for a helium plasma at different pressures, powers, and magnet field strengths. It is found that the magnetic fields produce higher electron temperatures with peak temperatures of ∼3 eV, while the no magnet case has peak temperatures of ∼0.8 eV. Conversely, the peak electron density is obtained in the no magnet case at a value of ∼1.9 × 1011 cm−3. This indicates that the cusp-field did magnetize the electrons, but contrary to expectations, it resulted in a decrease in electron density. This is believed to be due to the magnetic field having negative effects on the resonance of the plasma source. [ABSTRACT FROM AUTHOR]

Large-scale plasma plumes downstream of plasma jets are in urgent need from a practical viewpoint. In this Letter, an argon plasma jet with floating electrodes is proposed to produce a large-scale planar plume array. Results indicate that with increasing peak voltage (Vp), the planar plume array elongates gradually and scales up in the lateral direction to an optimal value of 90.0 mm. There is only one discharge pulse per voltage half cycle, whose intensity and duration increase with increasing Vp. Moreover, there is a time lag between the initiations of individual plumes. Fast photography reveals that the planar plume array originates from the repeated process of some micro-discharge filaments stretching along the argon stream. By optical emission spectroscopy, the spatial distribution of plasma parameters is obtained, such as electron density, electron temperature, and gas temperature. At last, the planar plume array is employed to test the surface modification of polyethylene terephthalate, for which a uniform modification has been realized with a scan velocity of 1.0 cm/min. These results are of great significance for the development of large-scale atmospheric pressure plasma sources. [ABSTRACT FROM AUTHOR]

The thermal effect of a single-dielectric-barrier-discharge plasma actuator under steady actuation is numerically investigated. A new actuator model is proposed and validated using experimental data. A discrete Galerkin method based on high-order flux reconstruction schemes is employed to solve the flow governing equations and the actuator model equations on unstructured quadrilateral grids. By comparing the induced heated and cold flow fields of the actuator with and without a plasma thermal source, its thermal effect is revealed. The actuator generates a thermal wall jet with rich vorticity, forming a monopolar starting vortex with a high-temperature and low-density core. Over time, the starting vortex becomes unstable and transforms into a dipole. Actuator heating enhances jet velocity and width, as well as vortex stability, while slowing down vorticity generation. The relative change in density and temperature fields due to actuator heating is four orders of magnitude greater than that without actuator heating. Additionally, the actuator heating causes the background thermodynamic fields to increase approximately linearly with time. Two stages in the actuator's thermal effect are distinguished due to time accumulation. Initially, the actuator heating minimally affects the monopolar starting vortex motion, and the temperature and density fields are treated as passive variables driven by the velocity field. During this stage, the momentum and thermal effects of the actuator can be studied separately. However, after the starting vortex becomes unstable, the actuator heating significantly impacts its motion and morphology, and these two effects are coupled with each other. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Inside extreme-ultraviolet (EUV) lithography machines, a hydrogen plasma is generated by ionization of the background gas by EUV photons. This plasma is essential for preventing carbon build-up on the optics, but it might affect functional performance and the lifetime of other elements inside the machine. The interaction of scanner materials and components with hydrogen plasma is investigated in controlled experiments using laboratory (off-line) setups, where the properties of EUV-generated plasmas are mimicked. Here, we present a novel experimental setup at TNO, where a low-temperature hydrogen plasma is generated by means of electron-impact ionization using a high-current, high-pressure electron beam (e-beam) gun. We show that the produced ion flux, peak ion energies, and radical-to-ion ratio are similar to that of the EUV-generated plasma. Since the e-gun has the option of operating the e-gun in the pulsed mode, it is possible to reproduce the time-dependent behavior of the scanner plasma as well. Moreover, as shown by Luo et al. [RSC Adv. 10, 8385 (2020)], electrons that impinge on surfaces mimic EUV photons in the generation of secondary electrons, which often drive radiation-induced processes (e.g., surface oxidation, reduction, and growth of carbon). We conclude that e-beam generated hydrogen plasma is a very promising technology for cost-effective lifetime testing of materials and optics, as compared to setups with EUV sources. [ABSTRACT FROM AUTHOR]

Plasma focus devices represent a class of hot and dense plasma sources that serve a dual role in fundamental plasma research and practical applications. These devices allow the observation of various phenomena, including the z-pinch effect, nuclear fusion reactions, plasma filaments, bursts, shocks, jets, X-rays, neutron pulses, ions, and electron beams. In recent years, considerable efforts have been directed toward miniaturizing plasma focus devices, driven by the pursuit of both basic studies and technological advancements. In this paper, we present the design and construction of a compact, portable pulsed plasma source based on plasma focus technology, operating at the ~2–4 Joule energy range for versatile applications (PF-2J: 120 nF capacitance, 6–9 kV charging voltage, 40 nH inductance, 2.16–4.86 J stored energy, and 10–15 kA maximum current at short circuit). The components of the device, including capacitors, spark gaps, discharge chambers, and power supplies, are transportable within hand luggage. The electrical characteristics of the discharge were thoroughly characterized using voltage and current derivative monitoring techniques. A peak current of 15 kiloamperes was achieved within 110 nanoseconds in a short-circuit configuration at a 9 kV charging voltage. Plasma dynamics were captured through optical refractive diagnostics employing a pulsed Nd-YAG laser with a 170-picosecond pulse duration. Clear evidence of the z-pinch effect was observed during discharges in a deuterium atmosphere at 4 millibars and 6 kilovolts. The measured pinch length and radius were approximately 0.8 mm and less than 100 μm, respectively. Additionally, we explore the potential applications of this compact pulsed plasma source. These include its use as a plasma shock irradiation device for analyzing materials intended for the first wall of nuclear fusion reactors, its capability in material film deposition, and its utility as an educational tool in experimental plasma physics. We also show its potential as a pulsed plasma thruster for nanosatellites, showcasing the advantages of miniaturized plasma focus technology. [ABSTRACT FROM AUTHOR]

Chemical functionalization of diamond surfaces by hydrogen is an important method for controlling the charge state of near‐surface fluorescent color centers, an essential process in fabricating devices such as diamond field‐effect transistors and chemical sensors, and a required first step for realizing families of more complex terminations through subsequent chemical processing. In all these cases, termination is typically achieved using hydrogen plasma sources that can etch or damage the diamond, as well as deposited materials or embedded color centers. This work explores alternative methods for lower‐damage hydrogenation of diamond surfaces, specifically the annealing of diamond samples in high‐purity, non‐explosive mixtures of nitrogen and hydrogen gas, and the exposure of samples to microwave hydrogen plasmas in the absence of intentional stage heating. The effectiveness of these methods are characterized by x‐ray photoelectron spectroscopy (XPS), and comparison of the results to density‐functional modelling of the surface hydrogenation energetics implicates surface oxygen ligands as the primary factor limiting the termination quality of annealed samples. Finally, photoluminescence (PL) spectroscopy is used to verify that both the annealing and reduced sample temperature plasma methods are non‐destructive to near‐surface ensembles of nitrogen‐vacancy (NV) centers, in stark contrast to plasma treatments that use heated sample stages. [ABSTRACT FROM AUTHOR]

A proof-of-concept study of the utilization of a single mass spectrometer for qualitative molecular analysis as well as for quantitative metal determination is described. This was performed with an argon microwave plasma as the ion source coupled to an ion trap mass spectrometer. A microwave induced plasma with tuneable power and gas flow rate was loaded with dried nebulized sample solutions. The commercially available plasma torch was slightly modified to allow the introduction of the sample in different regions of the plasma. Using soft settings, organic compounds introduced in the plasma plume could be detected as protonated molecular ions. Under harsher conditions, elemental analysis was demonstrated for several metals. Lead could be determined with a limit of detection of 150 nM. Minor on-the-fly adjustments of the power, flow rate and sampling distance allowed a mild fragmentation of organic compounds. Ionization differences observed were rationalized by emission spectroscopy, and excitation and rotational temperatures were determined. Simultaneous determination of elemental and molecular information was demonstrated for a rubidium–crown-ether complex. The maximum argon gas consumption for these tasks was below 2 L min−1 and the maximal power used was 90 W. [ABSTRACT FROM AUTHOR]

The higher harmonics generated by nonlinear sheath motion would enhance the standing wave effect, and thus lead to center-peaked plasma density profile in very-high-frequency (VHF) capacitive discharges. In this work, a nonlinear transmission line (NTL) model introduced in Zhou et al (2021 Plasma Sources Sci. Technol. 30 125017) has been extended, with radial transport of various particles and nonlinear sheath motion into account, to investigate the effects of CF4 fraction α on the nonlinear standing wave excitation and plasma radial uniformity in VHF (60 MHz) capacitively coupled Ar/CF4 plasmas at 3 Pa. The results indicate that for pure Ar discharges (i.e. α = 0%), the nonlinearly excited harmonics with short wavelength significantly enhance the electron power absorption at the radial center, resulting in a pronounced central-high plasma density profile. As α increases, the high-order harmonics are gradually damped due to the increase of resistance, as well as the longer wavelength caused by thicker sheath thickness. Thus, the radial profile of the electron absorbed power density shifts from center-peak to edge-high. Besides, at the radial center, the electron density and Ar+ ion density decrease with α , CF3+ ion density shows an increasing trend, while F− ion density initially rises and then decreases. Moreover, the density profiles of all the species become more uniform at higher CF4 fraction, due to the suppressed nonlinear standing wave excitation and the longer wavelength of the nonlinear harmonics. [ABSTRACT FROM AUTHOR]

Plasma treatment is necessary to optimize the performance of biomaterial surfaces. It enhances and regulates the performance of biomaterial surfaces, creating an effective interface with the human body. Plasma treatments have the ability to modify the chemical composition and physical structure of a surface while leaving its properties unaffected. They possess the ability to modify material surfaces, eliminate contaminants, conduct investigations on cancer therapy, and facilitate wound healing. The subject of study in question involves the integration of plasma science and technology with biology and medicine. Using a helium plasma jet source, applying up to 18 kV, with an average power of 10 W, polymer foils were treated for 60 s. Plasma treatment has the ability to alter the chemical composition and physical structure of a surface while maintaining its quality. This investigation involved the application of helium plasma at atmospheric pressure to polyamide 6 and polyethylene terephthalate sheets. The inquiry involves monitoring and assessing the plasma source and polymer materials, as well as analyzing the impacts of plasma therapy. Calculating the mean power of the discharge aids in assessing the economic efficacy of the plasma source. Electric discharge in helium at atmospheric pressure has beneficial effects in technology, where it increases the surface free energy of polymer materials. In biomedicine, it is used to investigate cytotoxicity and cell survival, particularly in direct blood exposure situations that can expedite coagulation. Comprehending the specific parameters that influence the plasma source in the desired manner for the intended application is of utmost importance. [ABSTRACT FROM AUTHOR]

The ITER Radial Gamma-Ray Spectrometer (RGRS) consists of three gamma-ray detectors observing the plasma through three collimated, coplanar, radial lines of sight (LoS). The system was initially designed to monitor the runaway electron emission and the alpha-particle density profile [Nocente et al., Nucl. Fusion 57, 076016 (2017)]. This work presents a novel technique for measuring the fusion power during D-T operation using the RGRS. This method is based on the absolute measurement of the 17 MeV fusion gamma-rays and a semi-analytical computation of their transport from the plasma source to the detectors. This approach was initially developed and tested at JET during the second D-T campaign (DTE2) on a single LoS diagnostic [Dal Molin et al., Phys. Rev. Lett. (submitted) (2024); Rebai et al., Phys. Rev. C (submitted) (2024); and Marcer et al., Nucl. Fusion (unpublished) (2024)]. This work exploits the multiple LoS of the RGRS to create a combined virtual diagnostic whose detected fraction of the total plasma emission is less affected by variations in the plasma emission profile, reducing systematic uncertainties on the estimated total emission, compared to the individual detectors. [ABSTRACT FROM AUTHOR]

The Space Plasma Environment Research Facility (SPERF) was built in Harbin to study the three-dimensional magnetic reconnection and wave–particle interactions relevant to space physics in laboratory settings. A 2.45 GHz Electron Cyclotron Resonance (ECR) plasma source is adopted in the device to simulate the Earth's magnetosphere and achieve the scientific goals. In this paper, the design of the ECR plasma source is presented. The structures of the microwave source, the microwave transfer system, and the antenna are introduced. Additionally, the resonant surfaces are computed to predict the locations of microwave absorption. The absorption mechanisms of the microwave in the SPERF are also discussed. The discharge experiment demonstrates the utility of the ECR source in simulating the Earth's magnetosphere. The successful operation of the source indicates that the ECR discharge is a powerful tool for creating a plasma environment in a large plasma experimental device. [ABSTRACT FROM AUTHOR]

Diagnosis of biliopancreatic cancers by the available serum tumor markers, imaging, and histopathological tissue specimen examination remains a challenge. Circulating cell-free DNA derived from matched pairs of secretin-stimulated duodenal fluid (DF) and plasma from 10 patients with biliopancreatic diseases and 8 control subjects was analyzed using AmpliSeq™ HD technology for Ion Torrent Next-Generation Sequencing to evaluate the potential of liquid biopsy with DF in biliopancreatic cancers. The median cfDNA concentration was greater in DF-derived than in plasma-derived samples. A total of 13 variants were detected: 11 vs. 1 were exclusive for DF relative to the plasma source, and 1 was shared between the two body fluids. According to the four-tier systems, 10 clinical tier-I–II (76.9%), 1 tier–III (7.7%), and 2 tier–IV (15.4%) variants were identified. Notably, the 11 tier-I-III variants were exclusively found in DF-derived cfDNA from five patients with biliopancreatic cancers, and were detected in seven genes (KRAS, TP53, BRAF, CDKN2A, RNF43, GNAS, and PIK3CA); 82% of the tier-I-III variants had a low abundance, with a VAF < 6%. The mutational profiling of DF seems to be a reliable and promising tool for identifying cancer-associated alterations in malignant cancers of the biliopancreatic tract. [ABSTRACT FROM AUTHOR]

In isotope concentration technology, ion extraction current and ion extraction efficiency are the key factors to measure the efficiency of the isotope concentration. In order to increase the ion extraction current, researchers usually hope to produce a plasma source with large initial peak density and width; however, in reality, it is limited by the laser power, and the total number of ions in a plasma produced by laser ionization is almost certain. In this case, how to improve the ion extraction efficiency by choosing the appropriate initial density distribution of plasma has become a difficult problem. In this paper, the effects of the initial density distribution of plasma on the ion extraction characteristics are studied by using the electron equilibrium fluid model. The numerical results suggest that the ion extraction efficiency is independent of the initial density distribution of plasma while the total number of ions in the plasma, the distance between the electrodes, and the electric field intensity are kept constant. When the total number of ions and the electric field intensity are kept constant, the distance between the electrodes is shortened by one time, and the time of ion extraction is also shortened by nearly one time; thus, the plasma source with high initial peak density and small width can be chosen, and the aim of ion extraction can be achieved by shortening the distance between the electrodes. This research results provide an important reference for guiding the experimental parameters such as laser power distribution and the design of ion extraction device. [ABSTRACT FROM AUTHOR]

To study the average contributions of the cusp outflow through the lobes and of the nightside auroral outflow to the O+ in the plasma sheet (PS), we performed a statistical study of tailward streaming O+ in the lobes, plasma sheet boundary layer|the plasma sheet boundary layer (PSBL) and the PS, using MMS/Hot Plasma Composition Analyzer (HPCA) data from 2017 to 2020. Similar spatial patterns illustrate the entry of cusp‐origin O+ from the lobes to the PS through the PSBL. There is an YGSM‐dependent energy pattern for the lobe O+, with low‐energy O+ streaming closer to the tail center and high energy (1–3 keV) O+ streaming near the flanks. Low energy (1–100 eV) O+ from the nightside auroral oval is identified in the near‐Earth PSBL/PS with high‐density (>0.02 cm−3), and energetic (>3 keV) streaming O+ with similar density (∼0.013 cm−3) is observed further out on the duskside of the PSBL/PS. The rest of the nightside auroral O+ in the PSBL is mixed with O+ coming in from the lobe, making it difficult to distinguish the source. We estimated the contributions of the different sources of H+ and O+ ions through the PS between 7 and 17 RE, using estimates from this work and data extracted from previous studies. We conclude that, during quiet times, the majority of the near‐Earth PS H+ are from the cusps, the polar wind and Earthward convection from the distant tail. Similarly, while the O+ in the same region has a mixed source, cusp origin outflow provides the highest contribution. Plain Language Summary: We studied the sources of the plasma sheet (PS), using MMS/HPCA data. We observed and mapped the location of the oxygen ions streaming from the dayside cusp region entering the PS through the plasma sheet boundary layer (PSBL). The observations of the oxygen ions from the nightside auroral oval streaming inside PSBL show that this population has higher density than the dayside cusp origin oxygen ions. We estimated the number of the proton and oxygen ions per second entering and leaving the PS and conclude that during quiet times, the solar wind protons are the major source for PS population and ionospheric oxygen ions from dayside cusp is the major source for oxygen ions in the PS. Key Points: Cusp‐source O+ is observed entering the plasma sheet (PS) from the lobe throughout the <25 RE magnetotailThe nightside auroral‐source O+ is identified at <100 eV inside 10 RE, with a more energetic component further out on the dusksideWe estimate that during quiet times, the dayside cusp contributes the most to the near‐earth PS O+ [ABSTRACT FROM AUTHOR]

The solar wind‐magnetosphere‐ionosphere interaction at Jupiter is reproduced numerically adopting the nine‐component magnetohydrodynamic simulation. Calculations take into account the magnetosphere‐ionosphere coupling, Jovian rotation, and Io plasma source. High‐speed rotating plasma inside restricted magnetospheric space causes expansion and contraction of magnetic field, forming super‐rotation at radial distance 20∼30 Rj and co‐rotation breakdown further outside. Field‐perpendicular current that restores co‐rotational delay beyond 30 Rj is connected via field‐aligned current to the main oval in the ionosphere. Inside 20 Rj, there is almost co‐rotation region (deviation from co‐rotation less than 20 km/s). Particularly within 10 Rj, the deviation from co‐rotation is less than 2 km/s. In the nearly co‐rotating region, the Io plasma forms a disk structure through field‐aligned redistribution. The interchange instability occurs near the outer wall of the Io plasma disk, and instability flow develops to vortex. Through this instability, a part of the centrifugal drift current supporting the Io plasma disk is connected to low‐latitude field‐aligned current that generates beads‐like spots on the lower latitude side of the main oval. Resulting interchange instability comes to satisfy the structure of convection and enables further development of vortex. The Coriolis force acting on eastward flow inside the developing vortex makes this flow protrude further outward, forming eastward bending fingers. Inside 10 Rj, Io plasma transport by the interchange instability becomes slower, despite the center of the disk. Io plasma escapes from the inner magnetosphere with a time constant of 20 days if this slow transport is taken into account. Key Points: We numerically reproduce the Jovian solar wind‐magnetosphere‐ionosphere interaction, considering planetary rotation and Io sourceOutward diffusion of Io plasma is facilitated by the interchange instability that occurs as vortex motion obeying the M‐I couplingFingers that develop in the Io plasma disk extend eastward in the region where the Coriolis force acts to accelerate the instability [ABSTRACT FROM AUTHOR]

The commonly utilized nitriding steel 38CrMoAl is employed for components subjected to low-impact loads but high wear. In this investigation, 38CrMoAl underwent plasma nitrocarburizing using a hollow cathode plasma source, with variations in gas ratios aimed at process optimization. The findings revealed a noteworthy influence of the NH3 to CO2 ratio on the phase composition and properties of the nitrocarburizing layers. Two distinct surface types were observed: one composed of ɛ-Fe2–3(N, C) and γ'-Fe4N and the other consisting of nitrogen-containing martensite with a small quantity of nitride. The surface comprising iron nitride was formed via downslope diffusion, leading to increased surface hardness through nitride formation. Nitrogen-containing martensite was formed via uphill diffusion due to spinodal decomposition, reinforced by mechanisms including fine-grain strengthening, solid-solution strengthening, secondary hardening during tempering, and the pinning effect of metal nitrides precipitated at the grain boundaries. The spinodal structure exhibited superior properties, with a wear rate of 1.26e − 8 mm3/Nm. Thermodynamic calculations confirmed that nitrogen diffusion facilitated spinodal decomposition by expanding the spinodal gap and reducing system energy. This study successfully overcame the performance constraints associated with such nitrided layers, which holds promise for applications to other nitride materials. [ABSTRACT FROM AUTHOR]

The aims of this study encompass the characterization of process parameters and the antimicrobial potential during operation of a novel non-thermal plasma (NTP) source in a duct system containing a particulate matter (PM) filter thus mimicking the interior of an air purifier. Simulating conditions of a long-term operation scenario, in which bacterial aerosols in indoor environments accumulate on PM filters, the filter surfaces were artificially inoculated with Escherichia coli (E. coli) and exposed to an air stream enriched with reactive species. Electrical power consumption, key plasma parameters, volume flow and air flow velocity, reactive gas species concentrations as well as inactivation rates of E. coli were assessed. The NTP operated at a gas temperature close to ambient air temperature and featured a mean electron energy of 9.4 eV and an electron density of 1∙1019 m−3. Ozone was found to be the dominating reactive gas species with concentrations of approx. 10 ppm in close vicinity to the PM filters. An inactivation rate of 99.96 % could be observed after exposure of the PM filters to the gas stream for 15 min. This inactivation efficiency appears very competitive in combating realistic bacterial aerosol concentrations in indoor environments. [ABSTRACT FROM AUTHOR]

Microwave plasma is known for its versatility in providing tailored operating conditions (pressure, working gas composition and residence time of reagents) for specific applications. Microwave plasma sources (MPSs) are vital in modern applications, demanding continuous improvement. This work introduces a coaxial-line-based nozzleless MPS that operates at atmospheric pressure at an unique frequency of 915 MHz. The measured electrodynamic characteristics in nitrogen of the MPS highlighted the need for improved energy efficiency of the device. The main novelty of this work lies in improving an energy efficiency of the presented MPS, which led to an advanced new version of the device. To achieve this, a dual strategy is employed. Firstly, numerical simulations are used to design a construction modifications to the MPS, which should increase the efficiency of transferring microwave energy from the microwave source to the generated plasma. In this step, a standard model for homogeneous plasma and a two-port equivalent method were used. Then, the theoretical results were experimentally validated by manufacturing a new energy improved version of the MPS. In the new MPS the achieved reflected microwave power (losses) was less than 3% of incident microwave power in the tested range of nitrogen flow rate (50–100 Nl/min). Compared to the MPS before improvement, this means a two-fold decreasing the reflected microwave power. To test the new MPS, the electrodynamic characteristics of the new device version and properties of the microwave plasma generated in nitrogen, using optical emission spectroscopy (OES), were investigated. The OES was used to determine the vibrational Tvib and rotational Trot temperatures of nitrogen molecules and molecular ions. In this work, the estimated Tvib and Trot temperatures for nitrogen molecules ranged from 4000 to 5300 K, depending on discharge conditions, while for nitrogen molecular ions, the temperatures changed between 4700 and 6100 K, respectively. Both the Tvib and Trot temperatures decrease linearly along the plasma flame. [ABSTRACT FROM AUTHOR]

The Saha-IESC (Saha Ionisation Equilibrium Shift Correction) is a novel approach designed to correct for ionisation interference in the analysis of various solution samples. It integrates the Saha equation, plasma electroneutrality, the ideal gas equation, and the mass conservation equation to determine electron densities and the densities of various particles. Then, it establishes a correlation between spectral line intensities, particle densities, and concentrations, allowing for accurate quantitative analyses. For plasma sources deviating from LTE (Local Thermodynamic Equilibrium), the model introduces a variety of plasma temperatures. Saha-IESC can accurately quantify both macro and trace elements without strict matrix matching between the standard and samples to be tested. Nor does it require a large number of samples as in machine learning. When combined with the concept of spectral standardisation, it can also correct the spectral intensities. After calibration, the R2 values of the calibration function of elements in the certified reference materials (CRM) GWB(E)130459 were improved from 0.7599–0.9971 to 0.9902–0.9999. And the detection accuracies for several elements in the two certified reference samples were in the range of 90–104% (GWB(E)130459) and 89–102% (BWR3030-2016), respectively. The robustness of the model was assessed through spiked recoveries of six elements in four brines. The range of spiked recoveries was 94–150% (external standard), 97–152% (internal standard), and 80–120% (Saha-IESC), respectively. The Saha-IESC can greatly reduce the complexity of experimental design, while effectively suppressing the ionisation interference. [ABSTRACT FROM AUTHOR]

The Juno mission flew through the plasma disk near the equator in Jupiter's magnetosphere frequently. We identify 274 plasma disk crossings of Juno between 10 and 40 RJ from PJ5 to PJ44. Using a forward modeling method that combines the JADE‐I time‐of‐flight and SPECIES data sets, we perform a survey of ion properties in the plasma disk. Ions are heated from 1.5 to 6 keV between 15 and 30 RJ. Density and temperature are locally anti‐correlated. Assumed to be related to centrifugal instabilities, cold, dense plasma are commonly observed near midnight. Plasma corotates around Jupiter and the rigid corotation breaks down outside 15–20 RJ. The plasma bulk velocity increases from the post‐dusk sector to the pre‐dawn sector featuring injection flows in the pre‐dawn sector, which is consistent with the Vasyliunas cycle. Strong outflows (>100 km/s) are commonly observed outside 20 RJ and the average radial velocity increases with radial distance. The ion abundance changes between 10 and 18 RJ and that might indicate plasma sources and/or sinks near Europa and Ganymede. The vertical distribution of ions is controlled by the balance between centrifugal, pressure gradient, and ambipolar electric field forces. An example near the M‐shell of 13.5 shows that average plasma temperature increases by a factor of 10 from the disk center to edge, because cold ions are more confined near the equator. Lighter ions with higher charge states have more mobility along the field line and have larger scale heights. The observations are compared with multi‐species diffusive equilibrium model. Key Points: The ion properties of the plasma disk are investigated based on 274 plasma disk crossings of Juno on Jupiter's nightsideStrong outflows are observed frequently outside 25 RJ and corotational velocity increases from the post‐dusk sector to the pre‐dawn sectorColder (hotter) and heavier (lighter) ions with lower (higher) charge states are more (less) confined near the equator [ABSTRACT FROM AUTHOR]

Our study explores the potential of a novel microwave plasma source for enhancing wound healing in BALB-C mouse models. Chronic wounds, particularly in diabetic individuals, present significant challenges due to impaired regenerative capacity. Cold Atmospheric Plasma (CAP) has emerged as a promising approach, offering diverse therapeutic benefits. However, its specific efficacy in the context of diabetic wounds remains underexplored. We developed and characterized a microwave plasma source optimized for wound treatment, inducing acute wounds and treating them with CAP in a controlled experimental setup. The treated group exhibited accelerated wound closure compared to controls, suggesting CAP's potential to enhance the healing process. Our findings underscore CAP's multifaceted impact on the wound healing cascade, highlighting its ability to promote angiogenesis, modulate inflammatory responses, and exhibit antimicrobial properties. These results position CAP as a promising intervention in acute wound management, paving the way for further exploration of its therapeutic potential in clinical settings. [ABSTRACT FROM AUTHOR]

Plasma technology, relatively new in the fields of biomedicine, agriculture, and ecology, is the subject of intensive research as a prospective means of decontamination of various microorganisms (bacteria, viruses, and fungi). The objectives of the present study were to follow the effect of cold atmospheric plasma (CAP) treatment on in vitro grown plum plants (Prunus domestica L. 'Kyustendilska sinya' cv.) and the possibility of eradicating or inactivating plum pox virus (PPV) causing Sharka disease by CAP. The source tree is naturally co-infected by PPV (both M and D strains). In the experiments, two different plasma sources were used. First, a surface-wave-sustained Argon plasma torch and second, an underwater diaphragm discharge. For the treatments, nodal segments (10 mm in length) from in vitro cultured plum plants with or without one leaf were prepared. Apical shoots from treated plants (PPV-positive and negative clones as well non-treated controls) were cultivated in vitro for four passages. Then they were rooted and acclimatized to ex vitro conditions, and their virus status was observed periodically for more than 3 years after treatment for the appearance of Sharka symptoms. All plants, acclimatized to ex vitro conditions, were tested for PPV by immune capture–reverse transcription–polymerase chain reaction (IC-RT-PCR). As a first step in understanding the plasma treatment of living plants, a plasma treatment variant causing no damage must be established; this has been done in our previous works. Treatment of plants by plasma with parameters that have been carefully selected leads to better development than the non-treated plants. In the treated in vitro plants, no significant differences were found in the number and length of shoots compared to the control plantlets. In ex vitro acclimated plants, greater stem length was reported, but no differences in leaf number were observed. No significant differences in growth were recorded between the control and plants that were treated twice or three times. At this stage, 3 years after ex vitro cultivation in a greenhouse, Sharka symptoms were not registered on treated in vitro negative PPV plants, and the virus was not detected by IC-RT-PCR. Very mild symptoms were showing in CAP-treated PPV-positive plants. Development of typical Sharka symptoms on non-treated controls were observed. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the influence of reactive oxygen species (i.e., neutral O atom and O 2 + ion) on deposition rates and film thickness uniformity in tetraethoxysilane (TEOS) plasma, utilizing a combination of plasma-fluid dynamic and quantum chemical (QC) simulations. The plasma simulations employed an improved model based on a previous study [H. Li et al., Jpn. J. Appl. Phys. 58, SEED06 (2019)], specifically tailored for a TEOS/O2/Ar/He gas mixture. In the QC simulations, both flat and step silicon oxide (SiO2) surfaces were employed to investigate the adsorption behavior of SiO molecules, the predominant silicon-containing species in TEOS plasma. These simulations also enabled the examination of the rates of SiO molecule adsorption on SiO2 surfaces, facilitating a direct comparison with the sticking coefficients utilized in the plasma simulation. The results of QC simulations revealed that SiO molecules exhibited a higher energetic preference for adsorption on step surfaces than on flat surfaces, resulting in the formation of new SiOH surface sites. Meanwhile, the plasma simulations demonstrated a strong correlation between the deposition rate and film thickness uniformity and the generation of oxygen species, specifically O atoms and O 2 + ions, as well as their respective fluxes. This relationship takes precedence over the influence of TEOS or its fragments colliding with the surface. Notably, higher plasma source frequencies were found to enhance the production of atomic O, which contributed significantly to achieving higher deposition rates. [ABSTRACT FROM AUTHOR]

In this Tutorial, we consider plasma sources with applications to fusion devices and high energy accelerators. These ion sources typically produce negative ions from hydrogen-isotope gases, which are extracted through one or multiple apertures and accelerated to high kinetic energies. Next, they are either double stripped of two electrons to form positive ions used as precursors in accelerator devices or neutralized to produce a neutral beam injected in tokamak reactors. Contrary to the working conditions of most ion sources where volume production prevails, the mechanism of negative ion production by dissociative electron attachment on vibrationally excited molecules inside the plasma volume of fusion-type hydrogen-fueled high power discharges is mostly balanced by their destruction by detachment before being extracted rendering this means of producing negative ions rather inefficient. Surface production through the transfer of electrons from low work function metallic materials to the impacting atoms is the alternative solution to fulfill the requirements for the applications concerned. Negative ions are produced close to the aperture from which they are extracted. As a result, the analysis and understanding of the extraction mechanisms through experimental diagnostics is rather difficult due to the lack of accessibility and can only give a partial view. In addition, most of the experimental work is focused on the validation of requirements for the applications and not to the investigation of the fundamental processes that take place inside these types of sources. This Tutorial is focused on the description and understanding of the physical mechanisms behind the extraction and acceleration of negative ions from hydrogen plasma sources through modeling methods. We describe the numerical techniques of particle-based methods with a specific emphasis on particle-in-cell Monte Carlo collision algorithms. An analysis of the physical processes involved in driving the negative ions from the plasma source, across the apertures and inside the accelerator as reported in the literature, is presented in detail. This Tutorial concludes with additional and future works to be addressed in the coming years. [ABSTRACT FROM AUTHOR]

This paper reports the optical characterization of a controlled atmospheric-pressure dielectric barrier discharge (DBD) plasma source in air and Ar environments. In this study, Ar flow rate is held constant at 1 L/min while the operating voltages varied from 6.5 kV to 12.7 kV. Under these conditions, a calibrated commercial compact spectrometer covering the range from 200 to 850 nm was used to record the emission spectra of DBD plasma operating at different voltages, gap distances, and gas types. Using the Boltzmann distribution, we calculated the electron density ( $ n_e $ ne) and excitation temperatures in the plasma of air and Ar DBD at 2 mm gap distance . The emission spectra lines of the hydroxyl radicals (OH), $ {{N_{2}}} $ N2, and Ar ions are acquired at different operating conditions. According to the findings, the light intensity of Ar DBD is significantly higher than that of air DBD under the same conditions of operation. The intensity of the generated plasma spectrum is also shown to rise with both an increase in the input voltage and a decrease in the gap distance. The measurements also showed that the average temperature of the excited electrons is around 1.1 eV for air DBD and 0.11 eV for Ar DBD, while $ n_e $ ne for both is on the order of $ {10^{16}}\,{{\rm cm}^{-3}} $ 1016cm−3. These results show that as the working voltage increases, the plasma changes from a filamentary state to a homogeneous mode. Knowing the DBD parameters increases its chance to compete with traditional methods in many fields, such as water, polymers, and biomedical treatments. [ABSTRACT FROM AUTHOR]

An extended version of the R -matrix methodology is presented for calculation of radiative parameters for improved plasma opacities. Contrast and comparisons with existing methods primarily relying on the distorted wave approximation are discussed to verify accuracy and resolve outstanding issues, particularly with reference to the opacity project (OP). Among the improvements incorporated are: (i) large-scale Breit–Pauli R -matrix calculations for complex atomic systems including fine structure, (ii) convergent close coupling wave function expansions for the (e + ion) system to compute oscillator strengths and photoionization cross sections, (iii) open and closed shell iron ions of interest in astrophysics and experiments, (iv) a treatment for plasma broadening of autoionizing resonances as function of energy-temperature-density dependent cross sections, (v) a 'top-up' procedure to compare convergence with R -matrix calculations for highly excited levels, and (vi) spectroscopic identification of resonances and bound (e + ion) levels. The present R -matrix monochromatic opacity spectra are fundamentally different from OP and lead to enhanced Rosseland and Planck mean opacities. An outline of the work reported in other papers in this series and those in progress is presented. Based on the present re-examination of the OP work, opacities of heavy elements might require revisions in high temperature-density plasma sources. [ABSTRACT FROM AUTHOR]

Microwave plasma sources are used in various applications, but inefficiency can limit their usefulness. Researchers have investigated a new approach with which to improve efficiency by using a waveguide with a special tuner. A standard waveguide was compared to one equipped with a stub tuner, which allows for the fine-tuning of the electrical properties. The experiment used a frequency of 2.45 GHz and tested input powers of 1 kW and 1.5 kW. Experiments showed that waveguides with tuners transferred power more efficiently, with fewer reflected and more transmitted microwaves. While peak temperatures remained similar, the tuned waveguide produced a hotter plasma flame (30–60 °C) at the same distance. Notably, increasing the input power further boosted the flame temperature by 300 °C. These findings suggest that stub tuners can significantly improve the efficiency of microwave plasma sources. This paves the way for more efficient plasma generation technologies and potentially allows for applications requiring even higher power. [ABSTRACT FROM AUTHOR]

In recent years, there has been significant interest in quantum technology, characterized by the emergence of quantum computers boasting immense processing power, ultra-sensitive quantum sensors, and ultra-precise atomic clocks. Miniaturization of quantum devices using cold atoms necessitates the employment of an ultra-high vacuum miniature cell with a pressure of approximately 10−6 Pa or even lower. In this study, we developed an ultra-high vacuum cell realized by a miniature ion pump using a high-efficiency plasma source. Initially, an unsealed miniature ion pump was introduced into a vacuum chamber, after which the ion pump's discharge current, depending on vacuum pressures, was evaluated. Subsequently, a miniature vacuum cell was fabricated by hermetically sealing the miniature vacuum pump. The cell was successfully evacuated by a miniature ion pump down to an ultra-high vacuum region, which was derived by the measured discharge current. Our findings demonstrate the feasibility of achieving an ultra-high vacuum cell necessary for the operation of miniature quantum devices. [ABSTRACT FROM AUTHOR]

The integrity of the plasma membrane is critical to cell function and survival. Cells have developed multiple mechanisms to repair damaged plasma membranes. A key process during plasma membrane repair is to limit the size of the damage, which is facilitated by the presence of tetraspanin-enriched rings surrounding damage sites. Here, we identify phosphatidylserineenriched rings surrounding damaged sites of the plasma membrane, resembling tetraspanin-enriched rings. Importantly, the formation of both the phosphatidylserine- and tetraspanin-enriched rings requires phosphatidylserine and its transfer proteins ORP5 and ORP9. Interestingly, ORP9, but not ORP5, is recruited to the damage sites, suggesting cells acquire phosphatidylserine from multiple sources upon plasma membrane damage. We further demonstrate that ORP9 contributes to efficient plasma membrane repair. Our results thus unveil a role for phosphatidylserine and its transfer proteins in facilitating the formation of tetraspanin-enriched macrodomains and plasma membrane repair. [ABSTRACT FROM AUTHOR]

Recent multi-point measurements, in particular from the Magnetospheric Multiscale (MMS) spacecraft, have advanced the understanding of micro-scale aspects of magnetic reconnection. In addition, the MMS mission, as part of the Heliospheric System Observatory, combined with recent advances in global magnetospheric modeling, have furthered the understanding of meso- and global-scale structure and consequences of reconnection. Magnetic reconnection at the dayside magnetopause and in the magnetotail are the drivers of the global Dungey cycle, a classical picture of global magnetospheric circulation. Some recent advances in the global structure and consequences of reconnection that are addressed here include a detailed understanding of the location and steadiness of reconnection at the dayside magnetopause, the importance of multiple plasma sources in the global circulation, and reconnection consequences in the magnetotail. These advances notwithstanding, there are important questions about global reconnection that remain. These questions focus on how multiple reconnection and reconnection variability fit into and complicate the Dungey Cycle picture of global magnetospheric circulation. [ABSTRACT FROM AUTHOR]

This work examines China's mainstream journal ranking system from the Chinese Academy of Science (CAS), including its history, recent reforms, and current operation, with a particular focus on Physics of Fluids. Using official statistics, this paper analyzes the Physics of Fluids standings in the CAS system from 2015 to 2023. During these years, Physics of Fluids experienced a significant increase in both popularity and impact. Meanwhile, the CAS system underwent substantial reforms, including the newly proposed Advanced edition, which universally boosted fluids journal academic weights in China. Most notably, the brand-new Field Normalized Citation Success Index (期刊超越指数 or FNCSI) offered a new lens through which to assess academic journal impact. Statistics reveal that Physics of Fluids is in a promising position to become the fourth Tier 1 fluids journal to enter any of CAS's Major Categories (after the Annual Review of Fluid Mechanics, Nuclear Fusion, and Plasma Sources Sciences and Technology) and the first-ever non-review-only Tier 1 fluids journal to enter the Engineering and Technology (工程技术 E&T) Major Category. Finally, this paper suggests several directions for Physics of Fluids to direct future endeavors as it enjoys heightening popularity in China. [ABSTRACT FROM AUTHOR]

The method for determining the absolute plasma density in sources that create plasma in the strong magnetic field using the electron beam has been developed and tested. The results of plasma density measurements in the source of tubular plasma used in research on plasma relativistic microwave electronics are presented. It was shown that at time of switching-on plasma maser, for discharge currents of 5, 9, and 20 A, the plasma densities were (3 ± 0.3) × 1012, (5.5 ± 0.6) × 1012, and (9.5 ± 1) × 1012 cm–3, respectively. Comparison with the probe measurements previously performed, as well as with the numerical calculations made using the KARAT code, showed good agreement between the results of microwave measurements and numerical calculations, while the measurement error did not exceed 15%. The results of probe measurements much stronger deviate from the results of microwave measurements, which is associated with the presence of the strong magnetic field in the plasma source. [ABSTRACT FROM AUTHOR]

A new experimental method for creating void-free complex (dusty) plasmas under microgravity conditions is presented. The method is based on a pulsed operation mode of a four-channel radio frequency generator for plasma sustainment. A dust cloud of micrometer-sized particles can be immersed in the bulk of a low temperature plasma under microgravity conditions. It typically contains a central volume depleted of particles—the void—that prevents the generation of large, continuous clouds. Experiments performed at different neutral gas pressures and discharge volumes during the microgravity phase of a parabolic flight show that the central void is closed completely once the pulsed operation mode is applied. The particle cloud shape and the density distribution within the cloud are practically independent of the pulse period within the investigated parameter range and mainly depend on the overall discharge parameters neutral gas pressure and discharge volume. This indicates that the pulsed operation of the plasma source does not introduce new physical effects on the particles aside from the void closure. The proposed method has great potential for future application in experimental facilities dedicated to fundamental studies of large three-dimensional, homogeneous complex plasma systems in microgravity. [ABSTRACT FROM AUTHOR]