bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations of filaments at the TUMAN-3M tokamak
Authors: Yashin A Yu , Askinazi L G , Belokurov A A , Bulanin V V , Zhubr N A , Krikunov S V , Kornev V A , Lebedev S V , Petrov A V , Tukachinsky A S 
Published: November 2019

Abstract
Some factors limiting an increase in the plasma pressure at the periphery of the tokamak plasmas can arise when the improved confinement is achieved in the H-mode. It happens when the edge localized modes (ELMs) develop in tokamak plasmas, and the factors mentioned above manifested themselves in the form of quasi-periodic filamentary structures, or filaments. The formation of such structures results in the occurrence of the anomalous energy and particle flows onto the first wall and divertor plates of tokamaks. Studies of the filaments were previously performed at tokamaks with divertor configuration using various plasma diagnostic methods, including the Doppler backscattering method. The paper presents the first observations of the filaments at the TUMAN-3M, which is the tokamak with limiter configuration. The filaments were studied using the Doppler backscattering method. Plasma was probed by the double-frequency microwave radiation of the O-wave in the frequency range of 27–37 GHz. The data were obtained in the H-mode regime initiated by the pulsed gas injection, in which the ELM-like events are observed. The poloidal velocity of the filaments and their radial localization were determined, and the radial and poloidal sizes of the filaments were also estimated.
High-performance version of the RPB code based on graphic processors for determination of the plasma boundary in tokamaks
Authors: Zotov I V , Vysotsky L I 
Published: November 2019

Abstract
The operation of modern tokamaks is impossible without an effective system for controlling the plasma boundary during the discharge. In this paper, we consider a method for determining the plasma boundary on the basis of integral equations. A high-speed parallel code using GPUs was developed for this purpose. Different methods of parallelization of the algorithm have been considered. The possibility of processing the magnetic measurements in real time during experiments is shown. The effect of the technical parameters of GPUs (the number of cores, the data bus width, the amount of internal memory) on the performance is also shown. The simulation results for the T-15MD tokamak, currently under construction at National Research Center Kurchatov Institute, are presented.
Study of the stochastic clustering on the refractory material surface under the effect of plasma load in the PLM device
Authors: Budaev V P , Fedorovich S D , Martynenko Yu V , Karpov A V , Gerasimov D N , van Oost G , Lukashevsky M V , Lazukin A V , Gubkin M K , Sliva A P , Shestakov E A , Sviridov E V , Marchenkov A I , Voinkova I V , Rogozin K A , Gvozdevskaya D S , Zakletskii Z A 
Published: November 2019

Abstract
Tungsten plates were tested in stationary helium discharges in the PLM device. The duration of discharges in the PLM reached 200 minutes. A distinctive feature of this device is the stationary plasma confinement, which is advantageous for testing fusion materials, including materials of the divertor and first wall of a fusion reactor. During plasma irradiation in the PLM, the thermal load on the surface of the tested plates was more than 1 MW/m2. The temperature of the tested plates amounted to 1000°C and more. Stochastic nanostructures with dimensions of the structural elements of less than 50 nm, including fuzz-type structures, were observed on the processed surfaces of the samples.
Formation and time development of spark channel in strong magnetic field
Authors: Omarov O A , Omarova N O , Omarova P K 
Published: November 2019

Abstract
The characteristics of the spark channel plasma formed in the external longitudinal magnetic field are studied experimentally. In experiment, the current-voltage, optical, and spectral characteristics of the discharge were measured and analyzed. Synchronization of the pulsed electric and magnetic fields was performed. The effect of the magnetic field on the radial expansion of the spark channel, the shock wave formation, as well as the changes in the balance of energy and temperature in the ionized plasma of the high-pressure gas discharge were analyzed. It was found out that, in the strong longitudinal magnetic field, the temperatures of electrons and ions in the spark channel (ne
∼ 1018 cm−3) become equal. The current density, the plasma channel conductivity of the spark channel, and the specific energy deposition into the discharge increased. The channel plasma parameters were analyzed as functions of the external magnetic field.
Creation of dust structures and clusters in a glow discharge in a strong magnetic field
Authors: Karasev V Yu , Dzlieva E S , Pavlov S I , Novikov L A , Tarasov S A 
Published: November 2019

Abstract
During the last 5 years, the range of magnetic field applied in the studies of dusty plasmas extended to the strong field. In particular, it became possible to generate dusty plasma in a glow discharge in a standing striation in a field of 1 T. Features of the formation of dusty plasma in a strong magnetic field, such as its geometric shape, the size of the dust structure and its stability are discussed in this report. Additionaly, the dust component is used for the diagnosis of the glow discharge, because it reflects the geometric size of the dust trap. Experiments showed the tendency of the generated dust clouds to compress in the direction perpendicular to the magnetic field and lengthen along the magnetic field.
Methods for measuring parameters of ultra-wideband microwave radiation
Authors: Dias Mikhaylova D E , Ivanov I E , Strelkov P S , Shumeyko D V , Tarakanov V P 
Published: November 2019

Abstract
The plasma source of ultra-wideband (UWB) microwave radiation was developed. Operation of this source is based on amplification of the relativistic electron beam (REB) noise. The middle frequency of UWB amplifiers of this type is determined only by the plasma density and does not depend on duration of the high-voltage pulse at the cathode. This allows obtaining rather long signals with durations of about 200–300 ns and tuning the signal middle frequency from 2.2 to 3.8 GHz by means of varying the plasma density. A number of problems were solved, which occur in the course of measuring the UWB microwave signal parameters. In particular, a new method for measuring signal energy was developed, the optimal length of the receiving antenna used for recording the UWB radiation spectra was chosen, and the effective potential of the plasma UWB source was estimated. It was demonstrated that the energy of microwave signal is more than 10 J. The effective potential of the plasma UWB source was found to be approximately 400 kV for the signal with a middle frequency of 3 GHz that is comparable to that of other UWB microwave sources. It was also shown that the spectrum of the plasma UWB source is determined by its amplification band and by the oscillation spectrum of the current generated by the explosive emission cathode.
Analysis of optical spectra of microplasma discharges initiated by plasma flow on the surface of the grade 45 carbon steel sample
Authors: Ivanov V A , Letunov A A , Konyzhev M E , Kamolova T I , Dorofeyuk A A 
Published: November 2019

Abstract
The results are presented from studies of the optical emission spectra of the microplasma discharge. The discharge is initiated by the pulsed plasma flow on the sample surface made from the grade 45 carbon structural steel. The discharge was initiated at a voltage of 400 V applied to the sample and maintained by a pulsed current with an amplitude of ∼600 A and duration of 20 ms. The discharge plasma electron temperature was calculated using data on the relative intensities of the iron atom lines. Based on the recorded continuous spectra in the optical spectral range, the melt temperature and the state of aggregation of matter were estimated at the points of microplasma discharge localizaton on the sample surface. It was found that the melt temperature on the steel surface determined using data on the continuous spectrum is approximately 5000 K, while the electron temperature calculated using data on the line spectra of atoms is approximately ∼7400 K.
Microwave injector of plasma formed in a narrow coaxial resonator: experiment and computer simulations
Authors: Balmashnov A A , Butko N B , Kalashnikov A V , Stepina S P , Umnov A M 
Published: November 2019

Abstract
Under the conditions of simultaneous extraction of the ion and electron plasma components and the formation of a current-compensated plasma flow created in a narrow coaxial resonator by the ECR radiation, the radial distributions of the ion current at different mass flow rates of the working gas (argon) were obtained. The computer PIC simulations were performed using the three-dimensional numerical model in order to determine the intensity of the plasma flow as a function of the experimental parameters.
Ignition and combustion stabilization of multicomponent supersonic chemically active flows in low-temperature plasma conditions
Authors: Shibkov V. M 
Published: November 2019

Abstract
An electrodeless freely localized microwave discharge, a surface microwave discharge, a non-equilibrium non-stationary transverse-longitudinal pulsating discharge were used for ignition and combustion stabilization. The induction periods for various discharges and the possibilities of their application for supersonic combustion stabilization inside the direct-flow aerodynamic channels are experimentally determined. A comparison of experimental results with the data of mathematical modeling is presented.
Influence of the sign and magnitude of a surface charge on the breakdown voltage of a barrier corona discharge in Ar
Authors: Akishev Yu S , Balakirev A A , Medvedev M A , Petryakov A V , Trushkin N I 
Published: November 2019

Abstract
The topic of this article is related to the breakdown phenomena in the surface dielectric barrier discharge (SDBD). The surface charge, locally deposited on the dielectric barrier, changes markedly the configuration and intensity of the electric field both on the barrier and in the gas gap. In turn, a change in the local electric field affects the rate of ionization multiplication of electrons in this area and, accordingly, influences the breakdown conditions of both volume and surface barrier discharges. In the case of sinusoidal SDBD, the first breakdown in each next half-cycle will be controlled by the charge deposited on the barrier during the previous half-cycle. Contrariwise, if there are several successive breakdowns in the half-cycle, each next breakdown after the first one will be controlled predominantly by the charge and plasma created by the previous breakdown in this half-cycle but not only by the charge deposited in the previous half-cycle. These features of the SDBD breakdown were investigated by the example of the barrier corona in argon at atmospheric pressure in the pinto-plane configuration. This discharge allows us the controlling of the location of the deposited charge. Surface charge was deposited in advance and by the SDBD itself.
Buoyancy driven convection instability and related pulsing of continuous optical discharges
Authors: Yu Lavrentyev S , Solovyov N G , Shemyakin A N , Yu Yakimov M 
Published: November 2019

Abstract
Optical discharges find now ever expanding applications in science, engineering and medicine. In present study authors discuss the phenomenon of periodic pulsing of a continuous optical discharge (COD) on the base of original experimental results. In the literature there is no general agreement regarding the origin of the considered instability. Authors have obtained the dependence of oscillation frequency on the gas pressure and proposed semi-empirical relations to estimate pulse frequency pressure dependence observed. Regular self-sustained oscillations of COD plasma were explained by the pulsations of heated gas bubble surrounding COD followed by buoyancy driven vortex formation that was detected on schlieren images of convection zone. This kind of buoyant convection instability was determined to obey the same similarity law as cycling frequency of puffing or flickering in diffusion and premixed flames. The instability discussed can affect the performance of COD in some important applications such as high brightness broadband light sources, for instance.
Temperature distribution in the zone of graphite destruction by a nitrogen plasma jet
Authors: Kavyrshin D.I , Korshunov O.V , Sargsyan M.A , Chinnov V.F , Scherbakov V.V 
Published: November 2019

Abstract
Using the automated system of high-speed visualization and spatial-temporal spectral diagnostics, the destructive effect of an atmospheric pressured nitrogen plasma jet with a temperature of 0.7 - 1.0 eV on samples of isotropic and anisotropic graphite was studied. Measurements of the electron, vibrational, and rotational temperatures of the plasma in the zone of destructive interaction were performed, and the pattern of the spatial-temporal distribution of the products of graphite destruction (carbon atoms and cyanogen molecules) was revealed. The efficiency of local spectral analysis of near-surface plasma is shown using a combination of longitudinal and transverse periodic scanning of the emission spectra and recording of instantaneous 2D spectra of the selected spectral region containing the CN and N2
+ bands. The spectral estimate of the concentration of the graphite destruction main product (carbon atoms) is in quantitative agreement with the results of measuring the mass loss rate of the sample material, made by two-positioned visualization of its surface. In the zone of realizable heat loads of 0.5-1.5 kW/cm2, heating of the graphite surface to temperatures of 2800 ÷ 3600 K was achieved and the rate of loss of its material was 3-15 mg/cm2s, which is consistent with the literature data.
The operating mode of the water-cooled MHD accelerator of SMGDU with a magnetic field that changed along the channel
Authors: Baranov D S , Bityurin V A , Bocharov A N , Bychkov S S , Grushin V A , Kusmartseva E V , Tretyakova N V , Batura N I , Zhurkin N G , Kolushov N M 
Published: November 2019

Abstract
The work is aimed at solving the problem of creating in laboratory conditions hypersonic high-enthalpy gas flows that parameters are kept constant for 5-10 seconds. For this purpose the test section of the MHD channel with water-cooled electrodes and side walls was under investigation at the set up with a magnetohydrodynamic accelerator in TsAGI. A new series of runs was performed in which the MHD-acceleration stage was successively increased to 5 seconds. It was determined that the electrical and gas-dynamic characteristics of the MHD accelerator did not depend on the duration of the run. It was first demonstrated that the use of a magnetic field special shaped along the axis of the channel made it possible to avoid catastrophic damage to the side walls of the channel at the entrance and exit of the MHD accelerator, which increased the service life of the installation.
Magnetosphere response to stationary solar wind forcing at various plasma resistivities in 2D MHD simulation
Authors: Gubanov E V , Likhachev A P , Medin S A 
Published: November 2019

AbstractThe magnetosphere response to the stationary solar wind forcing at various values of the plasma resistivity is studied. The simulation is performed within two-dimensional (2D) MHD resistive model; the meridional plane is considered. The solar wind and southward interplanetary magnetic field (IMF) are supposed to be stationary. The calculations were carried out for two plasma resistivity valuesηp= {106; 104} Ω·m, assumed constant in the whole flow field. At higher plasma resistivity the steady magnetosphere convection (SMC) takes place; the solution is symmetric relative to thex-axis. At lower resistivity the sawtooth event is realized; the solution is quasi-periodic and asymmetric. The asymmetry is connected with the formation of the vortex street of Karman type. The sequence of phases of the sawtooth cycle, as well as the evolution of magnetic lines of force and the flow structure in each phase is analyzed. In both solutions the day side magnetic reconnection occurs through the two x-points disposed symmetrically at the top and bottom peaks of the magnetic island.
Erosion of the sputtered electrodes in the surface barrier discharge
Authors: Selivonin I , Lazukin A , Moralev I , Krivov S , Roslyakov I 
Published: November 2019

Abstract
The paper is devoted to a phenomenological study of the modification of sputtered electrodes in a surface dielectric barrier discharge in atmospheric air. A decrease in the power supplied to the discharge in the case of using platinum and aluminum electrodes and an increase in the case of using a copper electrode were demonstrated. It is shown that during long-term operation of the electrode system, a decrease in its cold capacitance is observed. These effects are assumed to be due to the degradation of the electrode material, transfer of erosion products to the surface of the dielectric, as well as morphological changes at the electrode edge.
Classification of vector lines and fields by geometric and numerical methods
Authors: Burakhanov B.M 
Published: November 2019

Abstract
Geometric and numerical methods of classification of vector lines and vector fields are proposed. The division of vector lines of arbitrary vector fields into potential and spiral lines is carried out. The division of vortex vector fields into layered and spiral vector fields is carried out.
It is shown that any vector field can be represented as a superposition of layered vector fields.
Conditions of existence of so-called forceless spiral vector fields are established.
The mathematical conditions to be satisfied by the magnetic fields of magnetic clouds of the solar wind are formulated.
Influence on separation point position by rapid local gas heating with spark discharge on the surface of airfoil streamlined by supersonic airflow
Authors: Saveliev A S 
Published: November 2019

Abstract
Experimental investigation of interaction between gas-dynamic perturbations caused by long spark discharge and separation region on the surface of an aerodynamic model, streamlined by supersonic airflow with Mach number M=2, is presented in this paper. A NACA-airfoil with a relative thickness of 12% of the chord length was used as aerodynamic model. With the help of the Particle Image Velocimetry method airflow was visualized at various angles of attack, delays 0–100 μs relative to the moment of discharge initiation and at various values of stored electric energy 0.1–10 J, that was spent for discharge creation. It was found that the flow disturbance caused by the discharge leads to a short-term displacement of separation point downstream.
How the three Gorges Dam affects the hydrological cycle in the mid-lower Yangtze River: a perspective based on decadal water temperature changes
Authors: Xiong Yu Jiu , Yin Jing , Paw U Kyaw Tha , Zhao Shao Hua , Qiu Guo Yu , Liu Zhiyong 
Published: November 2019

Abstract
Three Gorges Dam (TGD), the world’s largest hydroelectric project in terms of installed capacity, alters the discharge and thermal regime of the Yangtze River in China, thereby threatening the aquatic biodiversity along the mid-lower Yangtze River. Thus, the influence of the TGD impoundment on the river temperature (T
w) and water cycle warrants in-depth examination. To the best of our knowledge, this study is the first to use decadal (2001–2013) Moderate Resolution Imaging Spectroradiometer temperature data to assess the impacts of TGD impoundment on the inland water cycle. We found that (1) spatially, the multiyear T
w decreased by 5 °C along the mid-lower Yangtze River, (2) temporally, T
w exhibited a warming trend after the operation of the TGD began, with most warming occurring from October to December directly after the TGD impoundment, and (3) the correlations between discharge and T
w in the pre- and post-TGD periods have changed; specifically, the closer to the TGD a location is, the greater the change in the relationship. Our analysis implies that downstream water temperature alteration is mainly attributed to the TGD management regime, and the influence is obvious along the 260 km river downstream of the TGD. It is likely that the impoundment of the TGD has increased the water residence time and slowed the water speed downstream.
Does exposure to inflammatory particles modify the pattern of anion in exhaled breath condensate?
Authors: Sauvain J-J , Edmé J-L , Wild P , Suarez G , Bezerra O M P A , Talvani A , Algranti E , Carneiro A P S , Chérot-Kornobis N , Sobaszek A , Hulo S 
Published: November 2019

Abstract
Exposure to environmental and occupational particulate matter (PM) induces health effects on the cardio-pulmonary system. In addition, associations between exposure to PM and metabolic syndromes like diabetes mellitus or obesity are now emerging in the literature. Collection of exhaled breath condensate (EBC) is an appealing non-invasive technique to sample pulmonary fluids. This hypothesis-generating study aims to (1) validate an ion chromatography method allowing the robust determination of different metabolism-related molecules (lactate, formate, acetate, propionate, butyrate, pyruvate, nitrite, nitrate) in EBC; (2) apply this method to EBC samples collected from workers exposed to quartz (a known inflammatory particle), to soapstone (a less inflammatory particle than quartz), as well as to controls. A multi-compound standard solution was used to determine the linearity range, detection limit, repeatability and bias from spiked EBC. The biological samples were injected without further treatment into an ion chromatograph with a conductivity detector. RTube® were used for field collection of EBC from 11 controls, 55 workers exposed to soapstone and 12 volunteers exposed to quartz dust. The analytical method used proved to be adequate for quantifying eight anions in EBC samples. Its sub-micromolar detection limits and repeatability, combined with a very simple sample preparation, allowed an easy and fast quantification of different glycolysis or nitrosative stress metabolites. Using multivariate discriminant analysis to maximize differences between groups, we observed a different pattern of anions with a higher formate/acetate ratio in the EBC samples for quartz exposed workers compared to the two other groups. We hypothesize that a modification of the metabolic signature could be induced by exposure to inflammatory particles like quartz and might be observed in the EBC via a change in the formate/acetate ratio.