A concept of the Globus-3 spherical tokamak with a “warm” copper electromagnetic system, developed jointly by employees of the JSC NIIEFA and the Ioffe Institute, is presented. By increasing the facility parameters to a plasma current of 2 MA, a toroidal magnetic field of 2 T, and an aspect ratio of 1.8, the expected ion temperature can reach thermonuclear values, which opens up prospects for studying the behavior of charged fusion products, including alpha particles. Using the iterative process, the major and minor plasma radii and the parameters of the poloidal magnetic system of the facility have been determined, allowing for achieving the required discharge plateau duration of up to 3 s. The plasma discharge scenarios are simulated. The choice of scenario parameters is based on data obtained during experiments on the Globus-M2 tokamak, as well as on calculations using the GLOBSYS code. The design variant proposed at this stage is recognized as the most preferable for the implementation of the Globus-3 facility with a copper electromagnetic system in the available experimental building of the Ioffe Institute.
An absolute error in measuring the plasma electric potential using the heavy ion beam probe (HIBP) is estimated for the T-15MD tokamak. The main sources of error are analyzed, including the instability of voltage and the inaccuracy of its setting in the high-voltage power supplies of the accelerator and the energy analyzer, the uncertainty in the entrance angle of the secondary ion beam into the analyzer, the noise in the measurement path and the shot noise. The error is calculated for various modes of tokamak operation with the toroidal magnetic field of BТ = 1.2–2.0 T and the chord-averaged electron density of ne = (3–5) × 1019 m–3 for different profiles of electron temperature and density. The radial plasma regions accessible to reliable potential measurement are determined. Two-dimensional distributions of the absolute error for both the average potential and its fluctuations are obtained. It is demonstrated that optimizing the analyzer plate voltage, which reduces the normalized difference in partial currents at the detector, reduces the overall measurement error by approximately a factor of four and substantially expands the sample volume.
Understanding the laws of confinement and transport of plasma at high electron temperature is a key issue in the field of plasma fusion research. The turbulent transport level of edge plasma is studied by using the Langmuir probe in NanChang Spherical Tokamak (NCST). The results show that electron heat conduction dominated by temperature diffusion due to temperature gradient occupies the center of the energy flow in the scrape-off layer (SOL) of NCST. In addition, it is observed that the contribution of electron heat convection resulting from the electron transport process gradually increases during the discharge process, with the ratio of electron thermal convection and electron thermal conduction increasing from about 15 to 44
The potential application of non-thermal plasma in treating textile industrial wastewater motivates researchers to develop innovative techniques at a laboratory scale to achieve the goal of wastewater mineralization. With this objective, a post-dielectric barrier discharge (DBD) plasma reactor with a liquid electrode has been developed to study the degradation of synthetic dye solutions (simulated dye wastewater) at the laboratory scale. The in-house-developed post-DBD plasma reactor is used to assess its applicability for degrading Crystal Violet and other azo dyes in aqueous solution (model wastewater samples). We investigated the roles of solution and reactor parameters in achieving a higher degradation efficiency of Crystal Violet under the given discharge conditions. The reaction kinetics of Crystal Violet degradation were studied by analyzing UV-Vis spectra at different treatment times. The primary results suggest that the proposed post-DBD plasma reactor may offer a more promising solution than a simple DBD plasma reactor for degrading synthetic dyes and organic matter in industrial wastewater.
This study investigates nonlinear ion-acoustic waves (IAWs) in a magnetized multi-ion plasma motivated by cometary plasma environments, where hydrogen ions, oxygen ions, and non-Maxwellian electron populations may coexist due to solar-wind interaction and particle acceleration processes. The distribution is adopted here as an effective model for electrons with superthermal tails, rather than as a universal description of all cometary electron populations. Two scenarios are analyzed: (1) oxygen ions follow Cairns–Tsallis distributions (CTD) while hydrogen ions behave as isothermal fluids, and (2) hydrogen ions adopt CTD while oxygen ions are governed by fluid dynamics. Using 3D fluid equations, reductive perturbation theory (RPT) and samll k perturbation expansion, we derive Zakharov–Kuznetsov (ZK) equations to describe nonlinear IAWs and their three-dimensional instability (TMI). Results reveal that wave features-such as phase speed, amplitude, width and instability growth rates depend critically on nonthermal electron parameter, nonextensivity, magnetic field orientation and basic plasma parameters. Notably, instability arises when specific threshold conditions are met, with growth rates sensitive to wave propagation angles. These findings deepen our understanding of wave dynamics in cometary and other space plasmas with non-Maxwellian components.
Diagnostics for measuring the value and spatial distribution of the effective ion charge Zeff(r): a key parameter characterizing the level of plasma contamination with impurities, have been developed and put into operation at the T-15MD tokamak. The proposed method is based on absolute measurements of the intensity of plasma bremsstrahlung in the visible spectrum. The diagnostic system is located in the equatorial plane of the installation and allows for recording the continuum along 12 toroidal observation chords. Absolute calibration of the system was performed in situ using a Labsphere USS-600C reference source. The paper analyzes the main sources of errors and evaluates the error in determining the Zeff value. The first experimental data on the average value of the plasma column cross-section ⟨Zeff⟩ obtained using this system during experiments on the T-15MD is presented.
A detailed analysis of the kinetics of atomic transitions in plasma under the influence of laser pulses of different structures has been carried out: spectral power density, pulse duration, and number of modes (spectral width). The difference between the results of the exact solution based on consistent non-stationary perturbation theory and the standard approach based on the use of Einstein coefficients for stimulated emission is demonstrated. The results of the analysis are demonstrated using experimental data on the observation of laser fluorescence signals for the helium plasma setup E-1 (prototype of plasma electrodeless plasma rocket engine with parameters (Te = 10 eV and Ne = 1013 cm–3). The paper uses a general approach to describe the kinetics of atomic transitions in plasma under the influence of laser pulses based on the results of the consistent application of non-stationary perturbation theory, which makes it possible to obtain the full probability of the photo process under the influence of pulses of different durations and spectral compositions. For different values of the spectral energy density of the laser pulse, the exposure time and the number of modes, the difference in the population of the laser pump level is shown for the exact solution that takes into account the structure of the laser pulse from the solution in the case of using the standard approach through the Einstein coefficients for stimulated emission.
An explanation of the dependence of the efficiency of electron cyclotron resonance heating (ECRH) on chord-average plasma density discovered during the analysis of experiments on-axis ECRH in the TJ-II stellarator is proposed. It is shown that the effect of decreasing heating efficiency with decreasing density can result from the excitation of a two-plasmon parametric decay instability (PDI) of the extraordinary microwave. The decay of the microwave (pump wave) occurs in two spatially close points as a result of the development of an absolute PDI leading to the excitation of electron Bernstein (EB) waves at frequencies close to half the frequency of the pump wave. The saturation of the instability is caused by secondary decays of the primary EB waves followed by the excitation of daughter wave pairs consisting of an EB and a slow lower hybrid (SLH) wave. The power deposition region of the daughter waves can differ substantially from that of the pump wave, which can explain the discovered discrepancy between the efficiency of ECR power absorption and the predictions of the standard linear theory. The daughter SLH waves, after linear transformation into ion Bernstein (IB) waves, can interact effectively with the ion component, which allows for a qualitative explanation of the appearance of superthermal ions discovered at the TJ-II installation during the ECRH.
The most interesting new results are discussed that were presented at the LIII International Zvenigorod Conference on Plasma Physics and Controlled Fusion, which was held in Zvenigorod, Moscow oblast, on March 16–20, 2026. The achievements in the main fields of research in plasma physics in Russia are analyzed and compared with those obtained in foreign scientific centers.
Specific effects inherent exclusively to plasma-dust systems that can be realized in the Solar System are considered. Particular attention is paid to such physical processes as anomalous dissipation in dusty plasma, fluctuation acceleration of dust particles, formation of a strongly-coupled state in dusty plasma, and in particular, a plasma-dust crystal.
A pseudospark switch with a trigger unit based on a pulsed surface discharge is investigated. The trigger system includes a semiconductor cylinder, on the surface of which there are two spring contacts. Initiation of a discharge in the high-voltage gap occurs when a trigger pulse at a level of up to 8 kV is applied to the cathode electrode. When a trigger pulse is applied, a cathode spot plasma forms in a wide range of gas (hydrogen) pressures up to atmospheric. To trigger the switch, it is necessary for the trigger discharge current to be intercepted to the grounded hollow cathode of the high-voltage gap. At low gas pressure (0.1 Torr or less), a discharge develops over the surface due to the trigger pulse, but current is not intercepted to the grounded cathode cavity. When the gas pressure increases to the working level (at a level of about 0.5 Torr), plasma is generated in the cathode cavity, which causes the external triggering of the device. The breakdown delay time relative to the instant of arrival of the trigger pulse includes the time of current interception in the cathode cavity and the time of initiation of the discharge in the main gap. It lies within the range of 55–70 ns, and its jitter for the considered trigger method does not exceed 10 ns.
As a novel air-breathing electric propulsion device, the single dielectric barrier discharge (SDBD) plasma thruster is ideal for long-endurance air-space vehicles. Using optical emission spectroscopy (OES), we systematically studied its plasma emission characteristics under air-space low pressures (10–100 kPa) and applied voltages (5–8.5 kV). Results show that the wavelengths of the molecular band heads of neutral molecules O2, N2, NO, O3, OH, the molecular ion O_2^ + , and of the atomic lines of hydrogen H and oxygen O concentrate in the 280–450 nm band, with only N2, N_2^ + , O_2^ + , and O present in the plasma. Optical emission intensity increases significantly with decreasing pressure and monotonically with increasing voltage. Within the experimental range, pressure and voltage only regulate the degree of ionization and particle number density, without altering plasma composition. This study clarifies the regulation laws of pressure and voltage on the plasma characteristics of the SDBD thruster under low-pressure conditions, and provides experimental basis and data support for the working condition matching and engineering design of the thruster on air-space vehicles.
The object of the study is domestic low-activation austenitic chromium–manganese steel (LAS) with a manganese content (22.4 wt
There has been significant interest in the decomposition of CO2 using nonthermal plasma in the last few decades. Nonthermal plasmas are acknowledged as a potentially effective strategy for reducing CO2 emissions by capturing them from waste gas streams and converting them into valuable chemicals and fuels. We present results from an experimental study on CO2 decomposition in three nonthermal plasma devices, namely dielectric barrier discharge, gliding arc with AC power supply and gliding arc with DC power supply. The effect of the applied voltage and the gas flow rate of CO2 on decomposition is investigated. The rate of CO2 decomposition is studied by detecting the amount of O2 present in the exhaust of the devices using a gas detector. The nonthermal plasma devices used in this study were found to be able to decompose CO2 gas. In addition to this, the gliding arc plasma with DC power supply has higher efficiency than the gliding arc plasma with AC Power Supply and dielectric barrier discharge plasma. Such plasma devices can be used to provide solutions to the problem of an increasing concentration of CO2 in the atmosphere of the Earth.
Results are presented from studies of the electrical explosion of 16-μm-thick aluminum foils with a perforation made using laser engraving, and the explosion of 7-μm-thick nickel meshes with 25.4 and 245 μm scale produced lithographically. The experiments were carried out using a high-current pulsed BIN generator (270 kA, 300 kV, 100 ns), whose main load was a molybdenum hybrid X-pinch. The studied foils and meshes were connected to the return circuit of the main load of the generator with a current of 60–80 kA. The images of the explosion products were recorded in each shot using point projection X-ray radiography in the X-pinch radiation and laser probing at two wavelengths. The influence of the perforation scale on the foil explosion was studied, as was that of the mesh structure period on the mesh explosion. It was shown that in certain foil and mesh configurations, a stabilization of the explosion scenario can be reached.
Measurements and studies of the hydrogen negative ion density have become an important topic in plasma physics. Here hydrogen negative ions are produced by the volume production technique in a hot cathode discharge. The density of negative ions is enhanced by a novel method using auxiliary filaments and conditioning the magnetic cage of the target region. Negative ion density is measured using the two-probe and ion acoustic wave techniques. The conditioning of the target cage enhanced the production of negative ions by almost 2 orders of magnitude and measurement of α = N_ - /N_e using the two techniques showed similar trend with each other. The measured values when compared theoretically by using the particle balance model, are found to agree qualitatively.
The pacemaker electrode and neurostimulators, energy storage devices (supercapacitors) are in contact with the electrolyte and should have the maximum possible capacity of the electrical double layer (EDL) and quickly release charge from EDL during discharge (to provide rapid depolarization of EDL). This requires the creation of porous coatings with a developed relief on them. This is often obtained by magnetron sputtering of metals (in particular, Ti). These coatings have columnar structure. It is proposed to use specially created micro irregularities on the substrate (initial substrate preparation) to increase the porosity of the coatings and the development of their relief. Mechanical (sandblasting) and laser treatments were studied. Helium plasma treatment was also investigated under conditions close to the conditions of metallic “fuzz” formation. It is shown that initial micro irregularities on the substrate increase significantly (2–3 times) the capacity of pacemaker electrodes and in some cases reduce the residual polarization of EDL for them.
Relativistic effects play a pivotal role in modulating the electronic structures and transition properties of highly charged ions in dense plasmas, especially for systems with mid-to-high nuclear charge numbers Z. In this work, the 1s–2p transition energies and transition probabilities of hydrogen-like ions (Z = 6, 18, 26, and 74) are calculated using the multiconfiguration Dirac–Hartree–Fock (MCDHF) method coupled with the self-consistent-field ion sphere model (SCFISM) or the ion sphere model (ISM) via GRASP2K code. The results show that relativistic effects depend strongly on nuclear charge number Z (following a Z2 scaling law) and increase significantly with electron density, while they decrease weakly and tend to saturate with increasing temperature. This work provides a reliable theoretical method for quantifying relativistic effects on the atomic spectra of hydrogen-like ions in dense plasmas.
The selection of dust particles in a plasma trap in the region of a double electric layer in a glow discharge formed by a sharp narrowing of the current channel created by introducing a dielectric insert into the discharge has been studied. The theoretical model of the formation of a double electric layer with a wider cross-section on the cathode side, available in the literature, has been analyzed. It has been shown that under typical conditions for dusty plasma in a helium discharge, the potential jump does not exceed 12 V. The selection of polydisperse quartz particles at low discharge currents has been experimentally studied; it has been found that there is a weak dependence of particle size on pressure. Under experimental conditions, the size of dust particles was about 4 μm. The use of dust particles as a kind of “dust probes” based on the estimation of the balance of vertical forces has showed the correspondence between the conclusions of the discussed theory and the experimental results.
A numerical solution of the stationary spatially homogeneous Boltzmann kinetic equation has been performed in the two-term approximation in mixtures of methane and water vapor in a wide range of reduced electric fields from 10 to 1000 Td (1 Td = 10–21 V m2) and the percentage of methane (from 0 to 100
