Abstract The shape is analyzed of the electron temperature profiles measured in experiments on the axial ECR heating at the L-2M stellarator at different densities and heating powers. It is ascertained that when the reduced ECR heating power exceeds some threshold value, the electron temperature profiles become broadened and flat in the core region of the plasma column. The correlation is revealed

Abstract Experiments on Experimental Advanced Superconducting Tokamak (EAST) were performed with high normalized beta (\({{\beta }_{N}}\sim 1.9\)) and favorable energy confinement (\({{H}_{{98,y2}}}\sim 1.1\)) for the operating space achieved in EAST. Gyrokinetic simulations were carried out for four different \({{\beta }_{N}}\) cases with the experimental plasma parameters and tokamak equilibrium

Abstract In the subthreshold microwave discharge (the wavelength of 4 mm) in argon at the pressure of 750 Torr at intensities of the wave beam from 3 to 7.8 kW/cm2, the velocity of the ionization front, measured from the phase change of the reflected wave, increases approximately as the intensity on the wave beam axis in the power of 3/2 from 0.5 × 105 to 2.9 × 105 cm/s. This velocity of the discharge

Abstract It is shown that the horizontal winds in Martian ionosphere, at the initial stage of their interaction with dusty plasma clouds at altitudes of about 100 km, can cause conditions for the excitation of dust acoustic waves due to the development of kinetic instability. The dispersion relationship of the dust acoustic waves is determined as well as their growth rate in the conditions under study

Abstract The results of studies of the spectral characteristics of the stochastic motion of charged particles in quasi-two-dimensional clusters in the electric field of a trap are presented. The characteristic particle frequencies and the method for their analytical calculation are considered. The analytical correlations are proposed for the spectral density of displacements in the low-sized clusters

Abstract— Electrodynamic properties of a low-pressure (electron collision frequency much lower than the field frequency) capacitive high-frequency (HF) discharge with large-area electrodes maintained by an electromagnetic field with frequency higher than 13 MHz is studied analytically. The discharge is sustained by surface waves propagating along the plasma–space-charge sheath–metal interface. When

Abstract A characteristic feature of the implosion of multiwire arrays on powerful high-current electrophysical facilities (ZR, Angara-5-1, Julong-1 (PTS), MAGPIE, etc.) is the process of extended wire ablation. It is based on the fact that the substance of the wires is not converted into plasma instantly, but is supplied into the discharge relatively slowly at the rate \(\dot {m}(t)\) in about 70–80%

Abstract The interaction of an additional electron beam with a previously created charged electron plasma of the squeezed state of two counter-propagating superlimiting electron beams in a closed equipotential cavity was studied numerically. The onset of plasma–beam instability in the absence of ions and quasi-linear relaxation is demonstrated. A significant broadening of the EDF towards higher electron

Abstract At the torsatron-type stellarator Uragan-3M, frequency spectrum and spatial structures of the fluctuations of the poloidal component of the magnetic field in frequency range 0.3–52 kHz, which are caused by the plasma current, are studied with a set of magnetic sensors. The studies were carried out in the microwave heating regime in confining magnetic fields of different strength. The magnetic

Abstract The results are presented from the theoretical analysis of the low-threshold parametric decay instability of the pumping microwave beam with the ordinary polarization and the frequency in the electron cyclotron resonance frequency range. This instability develops in the cylindrical plasma filament, which results in the excitation of two oblique Langmuir waves.

Abstract The flow of plasma with low gas-dynamic pressure transversely to the magnetic field, when electrons are transported under conditions of prevalence of collisions with neutrals, is studied theoretically and experimentally. Electron heating in the electric field formed by the plasma flow and electron drift (losses) to channel walls in the presence of the potential barrier between the walls and

Abstract Plasma–dust processes in the Earth’s ionosphere related to transit of meteor bodies and spreading of meteor trail are analyzed. Processes that occur in the meteor trail itself and those taking place in the Earth’s atmosphere upon transit of a meteor body, along with their influence on observers and operation of various technical systems, are investigated. In particular, mechanisms explaining

Abstract A calculated analysis of the possibility of achieving the generation in a gas-flow electric discharge oxygen–iodine laser when it is excited by a transverse slab RF discharge for various conditions of passing of the CF3I : O2 : He gas mixture components along the gas duct was carried out: in subsonic flow without cooling the channel walls and with cooling of various sections of the channel

Abstract Methods of description of ion–acoustic shock waves in dusty plasma are presented. A new type of dust ion–acoustic shock waves related to anomalous dissipation is described. The main dissipative processes related to charging of dust particles, absorption of ions by dust particles, Coulomb collisions between ions and dust particles, and Landau damping are analyzed. Proposed methods of theoretical

Abstract— An experimental study has been done of the bias effect of the active (high-voltage) electrode potential on the breakdown characteristics in a discharge tube 15 mm in diameter, filled with neon, argon, or their mixture (3 : 1) at a pressure of ~1 Torr. The bias of the potential is carried out by parallel connection to the electrode with an additional constant voltage or additional pulses with

Abstract The results are presented from studies of the efficiency of the quasi-optical wave beam tunneling through the opacity region in the vicinity of the plasma cutoff surface in the inhomogeneous magnetoactive plasma in the geometry corresponding to a large-scale axially symmetric open trap. In this geometry, the distinctive features are considered of the linear transformation of normal waves in

Abstract The study is continued of the temporal changes of the parameters of turbulent plasma density fluctuations during multi-pulse electron cyclotron (EC) heating of the plasma on the L-2M stellarator. The plasma density fluctuations with different wave vectors (k = 30, 20, 2, and 1 cm –1) in different spatial regions of the plasma column were recorded by the method of collective scattering of microwave

Abstract The results of the development of a two-dimensional MHD code for carrying out computational studies of the dynamics of plasma current sheath in spherical chambers with a plasma focus are presented. Equations of magnetohydrodynamics with allowance for magnetic field diffusion, thermal conductivity and plasma radiation are used in this work. An implicit scheme is used in the calculation of the

Abstract The review is devoted to studies of the processes and mechanisms of ignition of a glow discharge in tubes whose length significantly exceeds their diameter (long discharge tubes) at low pressures (~10 Torr and lower) and moderate voltage rise rates (~1 kV/μs and lower). The electric field in such tubes before a breakdown is substantially nonuniform. Therefore, a breakdown occurs after an ionization

Abstract The determination of the amplitudes of relativistic mKdV solitons based on specific amount of perturbation is presented for the first time in model of dusty plasma. The extremely high electrons’ streaming speed \({{v}_{{e0}}}\) is shown to enforce resultant relativistic speed of the bulk of plasma which necessitates smaller amount of perturbation to deal with the relativistic situation. Further

Abstract Compression of a fiber array with a deuterated target mounted on its axis is studied at the Angara-5-1 facility (3.5 MA, 100 ns). Cylindrical arrays with an initial diameter of 12 mm made from polypropylene fibers with a diameter of 13.4 µm are used. The number of fibers varied from 30 to 120. The target with the density of 0.08–0.2 g/cm3 and the diameter of 1 mm was made on the basis of deuterated

Abstract The noise amplification mode in a plasma maser with inverse geometry was obtained experimentally for the first time. It is shown that the introduction of a microwave absorber transfers the maser operating mode from the oscillator to the amplifier. In both modes, the tuning of the radiation frequency has been shown when the plasma density changes. This work is a step in the implementation of

Abstract The nonlinear stage of development of the dust particle chain instabilities is studied. It is assumed that dust particles interact with the plasma consisting of Maxwellian electrons and a directed flow of cold ions. The truncated equations are derived describing the nonlinear dynamics of the standing wave in the range of parameters close to the threshold for the development of the instability

Abstract In the framework of the isotope effect studies at the FT-2 tokamak, the efficiencies were compared of the lower hybrid wave heating of the ion components of the hydrogen and deuterium plasmas with high densities (close to the Greenwald limit, 〈ne〉 ≤ 1020 m–3). It was experimentally ascertained that, in accordance with the theoretical concepts, the efficient axial heating of the deuterium plasma

Abstract Propagation velocity of a subthreshold microwave discharge in air and carbon dioxide is measured at various gas pressures and intensities of microwave radiation. At air pressures of 200, 390, and 738 Torr and carbon dioxide pressures of 390 and 750 Torr, the propagation velocity of the head part of the self-non-self-sustained discharge closely follows a quadratic power law as a function of

Abstract Nonlinear propagation of ion-acoustic (IA) shock wave in a nonextensive and relativistic plasma is investigated by deriving space fractional Korteweg–de Vries–Burgers (SFKB) equation. This unmagnetized and collisionless plasma contains relativistic thermal ions, q-distributed electrons, and positrons. A modified tanh-function method is presented to solve the obtained SFKB equation taking space

Abstract The state-of-art of studies of processes involving small fractions of particles formed as a result of chemical transformations of the source gas or appearing from the outside as an impurity is discussed. Various high-sensitivity methods for measuring the low concentrations of particles are considered. The main focus is on spectral methods, both classical and laser ones. The main modern fields

Abstract A simple macroscopic method for detection of current sheet disruptions and determination of the width of metastable sheets is proposed based on the measurements of magnetic fields at the external surface of the vacuum chamber. This contactless diagnostic method does not affect the plasma processes in the current sheet and allows one to increase the signal-to-noise ratio. Such changes will

Abstract— The article deals with interaction of an extraordinary laser wave of high amplitude with inhomogeneous plasma in a strong magnetic field in the vicinity of twice the upper-hybrid frequency. The analysis is carried out by means of numerical simulation based on the particle-in-cell (PIC) method. It is demonstrated that in this case, parametric resonance leads to a substantial heating of electrons

Abstract Modeling of the pulse-periodic high-pressure cesium discharge on the basis of the radiative gas dynamic equations is executed. Calculation results of radial profiles of the plasma temperature, energy losses on radiation, electron densities and radial velocity of motion are given to various instants from the beginning of a current pulse. It is shown that the discharge under study makes it possible

Abstract A semi-empirical level-based model is developed that describes the detailed kinetics of the formation and decay of hydrogen atoms during relaxation of the vibrational energy of hydrogen molecules in the gas phase of a microwave discharge in liquid hydrocarbons in the range of the translational temperature from 600 to 3000 K at atmospheric pressure. It is shown that, depending on the conditions

Abstract In this study, many plasma parameters including excitation temperature \(({{T}_{{{\text{exc}}}}})\), electron temperature \(({{T}_{e}})\), skin depth \(({{\delta }_{p}})\), plasma potential \(({{V}_{p}})\), and electron energy distribution function (EEDF) are inspected in the two modes of magnetic pole enhanced-inductively coupled (MaPE-ICP) neon–argon mixture plasma by employing Langmuir

Abstract Formation and evolution of a density bump in an electrostatic shock wave during decay of a discontinuity in a plasma characterized by the presence of hot electrons and a large drop in plasma density across the discontinuity are investigated. Numerical particle-in-cell simulation in a wide range of plasma parameters revealed that the appearance of the density bump as a result of the action

Abstract— Modulational collapse of a wave pulse in a complex nonlinear plasma described by a complex nonlinear Schrödinger equation (CNSE) including the effects of viscous heating and nonlinear damping, and the adjusting by an external potential are investigated. Theoretical and numerical results reveal that the original pulse first suffers modulational instability, the growth rate of the modulational

Abstract Consideration is given to the formation of conditions and parameters of diffuse and volume discharges, which are widely used for laser generation in VUV, UV, visible and IR spectral ranges in different high-pressure gases and gas mixtures. It was found that spectral parameters of volume and diffuse discharges are similar. The difference between these discharge modes is found to be associated

Abstract— The conditions for the existence of spatially periodic flat nonlinear small-scale plasma and electric field structures with a characteristic size L on the order of several meters are found at altitudes of the D layer of the ionosphere. It is shown that for their description it is necessary to abandon the approximation of plasma quasineutrality, to take into account the presence of ions of

Abstract Propagation was studied of the ionization front of the gas discharge sustained by the microwave surface wave in a quartz tube filled with low-pressure air. In a wide pressure range, the characteristic propagation velocities of the discharge front were measured, as well as the parameters of the stationary plasma column. The experimental results obtained are in satisfactory agreement with the

Abstract A numerical simulation of the formation of plasma bunches in a long mirror machine under the gyromagnetic autoresonance was carried out in a magnetic field that increased with time. The process of the formation of plasma bunches with an energetic electronic component was studied as well as their time and space dynamics. The evolution of the energy spectra of the electron and ion components

Abstract— The magnetic flux through the diamagnetic loop consists of two parts: one is produced by the poloidal current in the plasma and another by the external currents. Separation of these parts is the focus of the study, which is fully analytical. The system is assumed to be axially symmetric. Then the “inductances” in the flux–current relations are expressed via easily tractable integrals. With

Abstract The energy exchange processes are studied in the systems of non-identical interacting particles (with different sizes, masses, and charges) with the spatially inhomogeneous distribution of the stochastic kinetic energy sources. To analyze the energy balance in such systems, a theoretical model is considered. The analytical relations are presented that describe the redistribution of the stochastic

AbstractHere we report the results of the turbulence study in the high-confinement mode (H-mode) with and without edge localized modes (ELMs). The study was performed by the Doppler backscattering (DBS) method on the Globus-M tokamak. Two types of ELMs were observed in the Globus-M tokamak during NBI heating and accordingly, two different transitions to transient ELM-free modes were discovered. It

Abstract—Results are presented of the particle-in-cell numerical simulations by the KARAT code of the formation of a plasma–beam discharge in the absence of both the longitudinal magnetic field and the initial plasma. Oscillations of the electric field generated by the plasma–beam instability in the electron beam region almost do not affect the plasma at the periphery of the system. Simulation results

AbstractDistinctive features of the drift motion of a nonrelativistic charged particle in slowly varying magnetic and strong electric fields, for which the assumption that the electric drift velocity is small as compared to the total particle velocity is non-applicable, are studied. The variational principles of the drift motion are extended to the case of the strong electric field. The generalized

AbstractThe propagation of planar and nonplanar electron-acoustic waves composed of stationary ions, cold electrons, superthermal hot electrons, and positrons is studied by using Korteweg–de Vries (KdV) equation in the planar and nonplanar coordinates. The analytical and numerical solutions of KdV equation reveal that the nonplanar electron-acoustic solitons are modified significantly with positron

Abstract—So far, the detailed experimental effect of the inductance on the X-ray yield in the Filippov-type plasma focus devices has not been documented in literature. In this paper, a 90 kJ Filippov-type plasma focus device is used to investigate the effect of three different external inductances (20, 40, and 60 nH) on the pinch current and neon soft X-ray (SXR) yield experimentally. The obtained

AbstractA specificity of the boundary between the photosphere and the chromosphere of the Sun consists in considerable acceleration of plasma spicules above this boundary and appearance of wave motions (predominantly Alfvén waves). Analytical solution to the equations of magnetic hydrodynamics is constructed in the vicinity of this boundary from the chromosphere side. Expressions describing the growth

AbstractIn the paper, experimental results concerning the dynamics of the counter interaction of high-energy plasma flows in a magnetic field with an induction of up to 2 T are presented and discussed. Plasma flows with velocities (2–4) × 107 cm/s, ion density (2–4) × 1015 cm–3, and energy content of 70–100 kJ were formed by two electrodynamic coaxial accelerators with pulsed gas injection. Nitrogen

AbstractModification of the beam tracing method for numerical simulations is proposed that allows one to use it in the zones of the microwave beam bifurcation, which is accompanied by the linear mode transformation. The theoretical basis for this modification is the switching over to the hybrid spatial-spectral representation of two beams, within which both the beam axes coincide and, therefore, the

AbstractGlobus-M2—a new 1-Tesla spherical tokamak—was recently launched. The main features and research directions of this machine in scope of fusion–fission reactor development are described. Main results of the first experimental campaign with toroidal magnetic field up to 0.73 T and plasma current up to 0.33 MA are discussed. Significant improvement of the discharge parameters as compared to Globus-M

AbstractThe etching characteristics of a patterned amorphous carbon layer (ACL) in a magnetized inductively coupled plasma (MICP) etcher were investigated. The etch rate and etched profile dependences on the source power, the neutral gas pressure and the dual bias power ratio were investigated. We measured the ion energy distribution (IED), the ion flux, plasma density and electron temperature using

AbstractWith allowance for the centrifugal and gradient drifts of ions, a new approximate dispersion equation is obtained for the ion Bernstein (IB) wave propagating strictly transverse to the external inhomogeneous magnetic field. Using this equation, it is shown that if, in the high-temperature plasma, the drift of ions is taken into account, the resonance frequency ranges in the vicinities of the

AbstractWe studied the propagation of small-amplitude dust ion acoustic (DIA) solitary waves in four-component relativistic plasma comprised of nonthermal electrons, mobile positively charged ions, positron beam and negatively charged massive dust particles. By using the reductive perturbation method, the Korteweg–de-Vries (KdV) nonlinear wave equation is derived numerically. In this work, we have

AbstractThe analysis is based on the relations characterizing charged particles’ motion in the drift approximation (D. V. Sivukhin, in Reviews of Plasma Physics, Ed. by M. A. Leontovich (Consultants Bureau, New York, 1965), Vol. 1, p. 1; B. A. Trubnikov, Introduction toPlasma Theory (Mos. Inzh. Fiz. Inst., Moscow, 1968) [in Russian]). It is noted that the particles can be accelerated using the device

Abstract—The dissipative divertor for the power and particle exhaust in a tokamak relies heavily on strong impurity radiation inside the divertor volume. In the present paper, the influence of the cross-field transport inside the divertor volume on the radiation loss by nitrogen and neon impurity seeding is studied in the SOLPS4.3 2D transport code. The study is carried out in a simplified tokamak

AbstractTwo stable operating mode, which were called “jet” and “bell” mode, were observed for Hall thrusters. These modes are distinguished from each other by the shape of the plasma plume and the anode efficiency. This paper presents the results of the measurements of the high-frequency floating potential oscillations using a Langmuir probe and of the relative erosion rate of boron nitride ceramic

Abstract—The formation of plasma on the surface of a current-carrying electrode of a high-current facility when a current flows through it with a linear density of up to 4 MA/cm and is coated with lead foil or ceramic is studied. The propagation velocity of a dense plasma from a stainless steel electrode is 2–10 km/s, and when the electrode is coated with lead, it is 1–6 km/s. In these experiments

AbstractTo better understand the arc plasma axial motion under an axial magnetic field, a high-speed charge-coupled device camera was used to observe the arc plasma images in a magnetically rotating arc plasma generator. Experimental results indicate that the arc plasma moves towards the cathode bottom as the magnetic field strength increases, while a higher arc current facilitates the cathode arc

AbstractFloating potential fluctuations (FPF) of the direct current magnetron sputtering plasma as a function of discharge voltage were observed. The system behaves chaotic to quasi periodic transition as the discharge voltage is increased. Detailed quantify examination is carried out using time series analyzing techniques such as Lyapunov exponent and statistical estimation to explore the dynamics

Abstract—The cathode plasma of a discharge in an electrolyte based on sodium carbonate and sodium hydroxide is studied as well as its interaction with the surface of electrolytes made from tungsten, tantalum, and titanium. The electrotechnical properties of the discharge are measured by spectral methods and the electron temperature of the near-cathode plasma is determined. When tungsten electrodes

Abstract—A self-consistent fluid simulation of inductively coupled plasma-enhanced chemical vapour deposition (ICP-CVD) using silane, argon, and hydrogen mixture is presented. The model solves the continuity equations for charged species, the drift-diffusion equations to describe their transport and the electron energy balance equation, coupled with Maxwell’s and Poisson’s equations, using COMSOL Multiphysics