Fizika plazmy
ISSN(Print): 0367-2921
Media registration certificate: No. 0110354 dated 03/02/1993
Founder: Federal Research Center "Institute of General Physics named after A.M. Prokhorov RAS", National Research Center "Kurchatov Institute", Russian Academy of Sciences
Editor-in-Chief: Smirnov Valentin Panteleimonovich
Number of issues per year: 12
Indexation: White List (level 3), Higher Attestation Commission List, RISC
Current Issue
Vol 51, No 3 (2025)
TOKAMAKS
OPERATIONAL RANGE, LIMITATIONS AND EXPECTED SIGNAL-TO-NOISE RATIO FOR THE DIAGNOSTIC “REFLECTOMETRY FOR ELECTRON DENSITY PROFILE MEASUREMENTS” FOR T-15MD TOKAMAK
Abstract
The operational limits and measurement range are assessed for the diagnostics “Reflectometry for measuring the electron density profile” developed for the T-15MD device. The recent changes in the diagnostics design are considered, the parameters of the diagnostics components are given, the expected signal-to-noise ratio is estimated. In conclusion, an assessment of the maximum level of density fluctuations at which the diagnostics retains its operability is given and compared with the results of measurements at other facilities. The work is of interest to specialists involved in the development of microwave diagnostics for thermonuclear facilities.
Fizika plazmy. 2025;51(3):251–269
251–269
PROCESSES DETERMINING THE ENERGY CONFINEMENT IN TOKAMAK PLASMAS
Abstract
In a brief review, we discuss the processes associated with plasma self-organization in tokamaks, and the model of the self-consistent pressure profiles formation used in the energy and particle balance equations. Plasma self-organization can be interpreted as the formation of a structure consisting from chain of magnetic islands, each of which can form a self-consistent pressure profile. The convergence of island chains leads to anomalous transport, and their divergence leads to the formation of transport barriers. In the proposed model, the total energy flux Γ consists of two main parts: Γ0 and Γ1, where Γ0 corresponds to a self-consistent pressure profile, and the anomalous turbulent flux Γ1 appears, when the pressure profile is distorted by additional heating/cooling, as well as the neoclassical flux Γneo. The electron pressure profiles obtained by Thomson scattering in plasmas with magnetic islands and the effect of sawtooth oscillations on the anomalous Γ1 flux are analyzed. We present examples of the plasma confinement deterioration due to the nonoptimal deposition of additional heating power, and the confinement improvement due to increased radiation losses at the edge, leading to diminishing the level of magnetic fluctuations, which can be associated with the divergence of the chain of magnetic islands or with a decrease in the size of the islands.
Fizika plazmy. 2025;51(3):270–281
270–281
МАГНИТНЫЕ ЛОВУШКИ
FEASIBILITY STUDY OF ELECTRON CYCLOTRON RESONANCE HEATING IN GOL-NB DEVICE
Abstract
The modeling results of various options for implementing electron-cyclotron resonance (ECR) plasma heating in the GOL-NB multiple-mirror trap are presented. Propagation and absorption of waves in ECR range are studied for a model radial plasma density profile both in the existing magnetic configuration and in a prospective one with an increased magnetic field in the central trap. Modeling reveals a possibility of efficient heating by an extraordinary wave at the fundamental harmonic for frequencies of 37 and 54.5 GHz. At the same time, there is a problem of “parasitic resonance” on the “outer” surface of the cyclotron resonance fromthe low field side. Heating by an extraordinary wave at the second harmonic can be relatively efficient for electron temperatures above 100 eV for frequencies of 75 and 95 GHz, which exceeds the plasma temperature currently achieved in the experiment.
Fizika plazmy. 2025;51(3):282–295
282–295
PLASMA DIAGNOSTICS
TECHNIQUE FOR PLASMA DIAGNOSTICS BASED ON RESONANCE LINES OF NE-LIKE KR XXVII ION AND ITS SATELLITES
Abstract
The X-ray spectral diagnostics of laser plasma of heavy elements that does not contain few-electron ions is considered. The X-ray spectral method for measuring the temperature and density of laser plasma of krypton cluster targets is developed. It is based on analyzing resonance spectral lines of Ne-like krypton ions Kr XXVII and their two-electron satellites arising due to transitions in Na- and Mg-like Kr XXVI and Kr XXV ions. Using the results of the calculations performed, it is possible to determine the ion density of plasma in the range of 1017–1021 cm−3 and the electron temperature in the range of 200–1000 eV. It is shown that one spectrometer with the spherically curved quartz crystal, which has a sufficiently high spectral and spatial resolution, can be used for experimental recording all required diagnostic spectral lines of krypton ions.
Fizika plazmy. 2025;51(3):296–303
296–303
BEAMS IN PLASMA
ROTATIONAL INSTABILITY OF THE AXISYMMETRIC TRIVELPIECE–GOULD MODES IN THE INHOMOGENEOUS ELECTRON BEAM
Abstract
Instability of axisymmetric electrostatic oscillations in an inhomogeneous beam of electrons confined by an axial magnetic field is studied within the framework of an ideal hydrodynamic model. The equation of perturbation of the beam electrostatic potential is derived in the linear approximation. It is demonstrated that the effects of differential beam rotation in self inhomogeneous electric field destabilizethe Trivelpiece–Gould modes. The spatial structure of the unstable eigenmodes is calculated analyticallyand numerically for model profiles of the beam density, and their spectrum is analyzed.
Fizika plazmy. 2025;51(3):304–312
304–312
SPACE PLASMA
ON ONE FEATURE OF THE PONDEROMOTIVE FORCE OF THE ION-CYCLOTRON WAVE IN THE NEAR-EARTH PLASMA
Abstract
The theory of ponderomotive forces in space plasma is an important component of solar- terrestrial physics. The problem that arises when using the classical formula of the ponderomotive force to analyze the acceleration of ions in the Earth’s magnetosphere under the influence of an ion-cyclotron wave is described. It consists in the fact that the force tends to infinity as thewave frequency approaches the local gyrofrequency of the ions. It is shown that the singularity arises as a result of idealizations inevitably adopted in constructing the standard theory of ponderomotive forces. Two limiting cases are considered: the case of a wide opacity band for ion-cyclotron waves, and the case of a narrow opacity band. Two methods for regularizing the ponderomotive force in the vicinity of the refractive index pole of the ion- cyclotron wave are proposed. One of them eliminates the singularity at the pole at the boundary of a wide opacity band, and the other at the boundary of a narrow opacity band. Examples of wave phenomena in near-Earth plasma are given, in the study of which it is necessary to take into account the singularity of the ponderomotive force calculated within the framework of the standard theory.
Fizika plazmy. 2025;51(3):313–319
313–319
TRANSFER PROCESSES
SECOND-ORDER MULTIGROUP MODEL FOR CALCULATING LOW-ENERGY ELECTRON TRANSPORT IN WEAKLY IONIZED GASES
Abstract
Proceeding from the Boltzmann kinetic equation for electrons, the system of multigroup equations for the zeroth, first and second moments of the electron distribution function is derived. The system includes equations for the balance of concentration, flux density and momentum flux density of electrons, and it is intended for numerical simulations of transport and kinetics of low-energy electrons in weakly ionized cold plasmas. The results of numerical calculations of electron swarm development in a uniform electric field in neon according to the developed multigroup model are compared with the results obtained by the Monte Carlo method to demonstrate the accuracy of the proposed model.
Fizika plazmy. 2025;51(3):320–331
320–331
LOW TEMPERATURE PLASMA
COMBINED PROBE AND OPTICAL LOCAL MEASUREMENTS IN A HOLLOW CATHODE DISCHARGE
Abstract
Using a moving Langmuir probe assembly and a fiber-optic sensor, simultaneous measurements of the electron energy distribution function EEDF f(u), their concentration Ne, and the emission spectra I(λ) of plasma with spatial resolution were performed in a discharge in inert gases at low pressure supported by a hollow cathode. The dynamic range of f(u) measurements is 5 orders of magnitude, while the observed ranges of Ne and I(λ) variations in space are up to 3 orders of magnitude. It was found that even small additions of Xe to He lead to significant changes in the EEDF shape, including in space. Within the framework of the coronal model (CM), the spatial profiles I(λ) of a number of lines of the Xe atom in a discharge in a He:Xe (99:1) mixture were calculated from the measured f(u) and Ne. Even in the approximation of this simple model, the results of the intensity calculations, on the whole, agree satisfactorily with the measured ones. A common method for measuring electron temperatures from the relative intensities of spectral lines of atomic transitions is discussed.
Fizika plazmy. 2025;51(3):332–341
332–341
CARBON DIOXIDE REFORMING OF METHANE IN ATMOSPHERIC PRESSURE GLOW DISCHARGE AT 50 HZ
Abstract
A chromatographic study of atmospheric pressure glow discharge products in a mixture of CO2 and CH4 has been carried out. The discharge has been ignited using a source at a frequency of 50 Hz and a discharge voltage of up to 10 kV. The main gas products at the discharge output are H2 (∼55%) and CO (∼40%). It is shown that the discharge properties are determined by the ratio of CO2 and CH4 consumption at the reactor input. Soot particles are formed in the discharge in addition to gas products at the same CO2 and CH4 consumption at the reactor input. The soot formation is suppressed and water vapor appears in the discharge when in the CO2 content in the mixture increases. The discharge current and voltage oscillograms have been analyzed and the energy required to obtain hydrogen and spent on decomposition of CO2 have been estimated.
Fizika plazmy. 2025;51(3):342–348
342–348