bluuebunny/crossref_metadata_2025_split huggingface dataset:
Beat Heating of Collisional and Magnetised Plasma
Authors: Arora B. B. , Phalswal D. R. , Varma N. L. 
Published: July 2007

AbstractThe heating of a plasma by stimulating plasma electrons as well as plasma ions with two anti‐parallel electromagnetic waves under the influence of a uniform static magnetic field is studied using Maxwell's equations and equations of motion. A formula for the power absorption per unit volume of the plasma is derived and effects of collisions and magnitude and orientation of the magnetic field on the beat heating are examined numerically. It is observed that the average power absorption in the absence of ion‐neutral collisions in the plasma barely exceeds unity in the units of pure Langmuir mode excitation where as in the presence of ion‐neutral collisions the power absorption immediately shoots up to a very high value.
The State of the Theory of Vacuum Arc Cathodes
Authors: Hantzsche E. 
Published: July 2007

AbstractThe physics of vacuum arc cathodes, the advances in their interpretation and the still unsolved problems are summarized. Starting from the experimental experiences the theories of stationary arc spots are described, with their assumptions and variants, their successes and deficiencies. It is shown that an extension of these models by inclusion of non‐stationary processes is inevitable. Such processes are suggested and their importance in a theory of the dynamic arc spot is investigated. Finally the role of surfacecontaminations is discussed, and the general applicability of the vacuum arc models to all kinds of arc electrodes is emphasized.
On the Rotational Distribution of N2 in the ArN2‐Discharge. The OO‐Band of the Second Positive System
Authors: Venzke D. , Mizeraczyk J. , Szczepanska H. , Korn E. 
Published: July 2007

AbstractThe rotational distribution of the OO‐band of the second positive system of N2 was determined by the Ornstein method in the glow discharge of an argon‐nitrogen mixture at medium pressure. Evidently, for the rotational R‐ and P‐lines some straight lines can be fitted for rotational quantum numbers between 2 and 60 according to usual representation. The slopes of the curves indicate that the Boltzmann distribution does not exist for all the levels. For each of these straight lines can be declared a value of rotational temperature. The dependence of the several rotational temperatures on the discharge current is essential lower than the corresponding dependence of the gas temperature, which is calculated by means of the energy balance. The influence of the energy transfer from metastable argon atoms to ground‐state nitrogen molecules on the rotational distribution seems to be insignificant. Comparisons with rotational distributions in pure nitrogen plasmas point at the influence of interactions between nitrogen species.
On the Maxwellian Regimes of the Electron Component in the Plasmachemical Reactors of Beam‐Plasma Type
Authors: Mikhailovskii A. B. 
Published: July 2007

AbstractA problem of description of the electron component in the plasmachemical reactors of beamplasma type is examined. Conditions under which the electrons have a velocity distribution close to the Maxwellian one are elucidated. A hydrodynamic approach for description of the electron component in the Maxwellian regimes has been suggested instead of the kinetic approach developed by Winkler et al. [Beitr. Plasmaphys. 19 (1979) 319]. A method of calculation of the non‐Maxwellian additive to the electron distribution function is formulated, for the proposed hydrodynamic approach to prove. A critical analysis of computer results found by the kinetic approach is given.
On the Theory of Corona Discharge
Authors: Belevtsev A. A. , Biberman L. M. 
Published: July 2007

AbstractFundamentals of microscopical theory of the corona discharge are considered. Main mechanisms of generation and disappearance of charged and excited particles are discussed for the example of the helium discharge. An important role of pair ionizing collisions of metastable particles is indicated. Field configurations and distributions of charged and excited particles in the discharge gap are obtained, the corona voltage‐current characteristics are calculated. It is shown that the presence of nonlinear ionization processes may result in hysteresis phenomena. In particular, on set and offset potentials of the corona discharge may differ considerably. Probable features of the corona discharges in some other gases are discussed qualitatively.
Metastable Decomposition of Ar3+ Cluster Ions Into Ar2+ and Ar+
Authors: Stephan K. , Märk T. D. , Märk E. , Stamatovic A. , Djuric N. , Castleman A. W. 
Published: July 2007

AbstractIn this note we present the first account of a study of metastable (unimolecular decay) and collision‐induced dissociation of Ar3+ cluster ions using an experimental setup consisting of a molecular beam‐electron impact ion source and a double focussing (reversed Nier Johnson geometry) mass spectrometer. The existence of the following metastable decay processes (accessible by our sampling time window) could be demonstrated: Ar3+* → Ar2+ and Ar3+* → Ar+. The processes were studied as a function of electron impact energy. The present results are of importance in order to provide some guidance for the development of appropriate theoretical models for the dissociation of cluster ions.
Dc Breakdown of Ultra‐High Vacuum Gaps
Authors: Nevrovsky V. A. , Rakhovsky V. I. , Zhurbenko V. G. 
Published: July 2007

AbstractA review of mechanisms of the initiation of vacuum breakdown is presented and role of anode surface contaminations in enhancement of prebreakdown currents and initiation of breakdown is emphasized. The experimental investigation of vacuum breakdown and prebreakdown phenomena is described. Experiments presented herein show the desorption of anode contaminations under electron bombardment to be an essential factor of stimulation of electrical breakdowns. Possible influence of desorbed gases on prebreakdown state of electrodes is analysed.
Ponderomotive Force Effects due to a Circularly Polarized Electromagnetic Wave
Authors: Stenflo L. , Tomaradze G. P. , Tsintsadze N. L. 
Published: July 2007

AbstractThe modifications in the time‐averaged plasma particle distribution functions in the presence of a large amplitude electromagnetic wave are studied. It is shown that the ponderomotive force is responsible for tail formation, non‐zero particle currents and heat fluxes. Explicit results, which describe those effects, are derived.
Emission Spectroscopic Investigation of the Decomposition of CCl4 in Plasma Etching Processes
Authors: Tiller H.‐J. , Breitbarth F.‐W. , Pfauch G. , Göbel R. 
Published: July 2007

AbstractThe CCl4 plasma decomposition and the etching of SiO2 and Al by the CCl4 plasma is investigated with the aid of emission intensity Iλ of such species as Cl2, CCl, Cl and CO, which are influenced systematically by the etching process. A time independent electron density (ne ≈ 2 · 108 −1 · 1010 cm−3, dependent on plasma conditions) is measured by microwave diagnostics. The ratio Iλ/ne and Iλ/Ireference' resp. (Ireference = IHelium) is a relative measure of concentrations. The ratio Icl2/Iccl is very sensitive against CCl4‐decomposition and etching processes of SiO2 and Al. Its changes during the etching process of SiO2 and Al in a CCl4 plasma are investigated.
Applicability of the Hydrodynamic Approach to the Electron Component in Plasmachemical Reactors of a Beam Plasma Type
Authors: Popkov N. G. 
Published: July 2007

AbstractIn the present work the question of the possible use of the hydrodynamic approach for describing a plasma beam discharge is investigated. It is shown that the condition νei > (νei + νen) X W/nT is the Maxwelliazation criterion of moderate energy particles in a plasma beam discharge. In this case the value of moderate energy is less than 3÷4 values of plasma electrons thermal ernergy.The influence of the tail of the distribution function on electron heating is considered qualitatively.
[Russian Text Ignored]
Authors: [Russian Text Ignored] [Russian Text Ignored] 
Published: July 2007

AbstractA theory of the magneto‐acoustic radiation from an upper‐hybrid soliton moving in an inhomogeneous magnetoactive plasma is presented. The derived expression for the spatial distribution of the radiation field is analysed for a linear and two different parabolic density profiles. The energy flux density connected with the transversal part of the magneto‐acoustic waves is investigated.
Measurement of Specific Heats Ratio of Hydrogen Plasma
Authors: Djurović S. , Pavlov M. 
Published: July 2007

AbstractAdiabatic expansion of plasma behind the reflected shock front in an electromagnetic shock tube has been verified. Electron densities and temperatures have been measured spectroscopically. Assuming complete local thermal equilibrium, the specific heat ratios of hydrogen plasmas have been determined out of expansion rate per a heavy particle directly from the adiabatic expansion law. Noticeably lower values of the ratio are determined at temperatures where ionization and recombination processes are abundant. The ratios determined in this work are in excellent agreement with theoretical values determined in an earlier work.
Perturbed Arcs in Turbulent Axial Gas Flow. I. Averaged Properties and Power Balance
Authors: Michel G. , Rothhardt L. 
Published: July 2007

AbstractElectric, caloric, radiation and sounding measurements are reported, which were done with an nitrogen are in strongly turbulent gas coolant flow. On the base of this measurements a power balance is established. It allows for the description of the are by a three‐zone‐model, the zones being 1. conducting are core, 2. thermal sheath containing dissociated nitrogen, 3. relatively cold coolant gas. The hot are core is gliding inside of the thermal sheath. The geometrical disturbances, discussed in a preceding paper, do so, too. The dominating power loss is by axial enthalpy flow out of the channel, carried by the dissociated nitrogen in the thermal sheath.
Experimental Investigations of Discharge Characteristics and Plasma Parameters of a Cylindrical Cathode Discharge in a Magnetic Field. II. Plasma Parameters
Authors: Pavelescu G. , Ghiţâ C. , Bâlâceanu M. 
Published: July 2007

AbstractThe experimental determination of the main plasma parameters (i.e. plasma potential, plasma density, electron temperature, intensity of plasma radiation) in the negative glow of a cylindrical cathode discharge in magnetic field is presented. The influence of electrode configuration, gas pressure, discharge current and magnetic field on plasma parameters and their radial distribution is analysed.
Perturbed Arcs in Turbulent Axial Gas Flow II. Fluctuating Local Properties
Authors: Michel G. , Rothhardt L. 
Published: July 2007

AbstractAs a continuation of the research described in Pt. I, local quantities are studied experimentally by electrostatic wall probing, time resolving shadowgraphy and radial luminosity profile scanning of arcs in turbulent axial gas flow. Turbulency of the gas coolant and thermal sheath properties are discussed as well as the consequencies of the gathered knowledge to theoretical modelling.
Stabilization of Long Electric Arcs by Rotating Magnetic Fields of Different Configurations
Authors: Novikov O. J. , Putko V. F. , Sobolev V. S. 
Published: July 2007

AbstractThe results of the investigation of the direct current electric arc under the influence on it of the rotating magnetic fields of the inductors with a different number of poles pairs are given in the article.The analysis and the comparison of the arc energetic characteristics and of its movement parameters in the rotating magnetic fields of different configurations were carried out.The comparison of the experimental data and of the results of the theoretical analysis of the arc movement in the 2‐poles and 4‐poles inductors fields was carried out.A number of original methods for the application of the researched type of the magnetic effect on the electric discharge in plasma techniques and technology was suggested.
Transport Equations of Plasma in a Curvilinear Magnetic Field
Authors: Mikhailovskii A. B. , Tsypin V. S. 
Published: July 2007

AbstractThe problem of transport equations of a collisional plasma in a curvilinear magnetic field is studied. Two main approaches to this problem are presented: that based on using the Boltzmann kinetic equation and the drift kinetic equation approach. In the frame of the first approach a multimoment transport equation set is found which is more general than the transport equation sets of Braginskii and Grad. The tensor equations of this set are described in an arbitrary curvilinear coordinate system. This allow to use these equations in problems of a plasma confined in toroidal magnetic configurations. Simplification of the multimoment transport equation set in the case of high magnetic field is performed. In the frame of the drift kinetic equation approach, a generalization of the drift transport equations derived earlier by the authors (Zh. Eksp. Teor. Fiz. 83 (1982) 139) is given.
Tomographic Measurements of Temperature Fields in Non‐Stationary Arc Plasma
Authors: Melnikova T. S. , Pickalov V. V. 
Published: July 2007

AbstractThe paper presents results of the use of computational tomography techniques for the processing of experimental data obtained with the help of a plasma tomograph. On the basis of the data acquired, physical processes have been determined taking place in plasma, and the behaviour of some integral characteristics of an electric are discharge in a longitudinal magnetic field has been explained. A possibility to determine optically a certain effective electric field strength of an unsteady state plasma has also been demonstrated.
Ion Extraction of Cl Containing Plasmas — Problems and Possibilities of the Investigations of Plasma Processes
Authors: Tiller H.‐J. , Göbel R. , Führ U. 
Published: July 2007

AbstractThe ion extraction is investigated from Cl2‐, SiCl4‐ and CCl4‐plasmas within a planer‐reactor in dependence on pressure and power density. Furthermore the relative ion formation cross sections of the ions fragments of these gases are measured versus the electron energy within a mass spectrometer tube. It will be concluded the decomposition of these gases from the measured ratios of the extracted currents of single ions in dependence on the plasma parameters. The extracted ion spectra extrapolated to a low degree of decomposition are compared with the ion fragments formed by electron impact within the mass spectrometer tube and thereby the effective electron energy in the plasma sheath nearby the orifice estimated.
Analytical and Numerical Study of the Dispersion Properties of a Beam Plasma System for the Case of Maximal Growth Rates
Authors: Leven R. , Bodrow W. 
Published: July 2007

AbstractA comparison is made between the analytical approximations for the maximum growth rate γmax and the corresponding values of the frequency and wave number, which are used as initial conditions in nonlinear theories and numerical experiments, and the results of an exact numerical solution of the Landau dispersion equation.
Mikrowellendiagnostik nichtstationärer Ne‐Plasmen mittels unterschiedlich bedämpfter Hohlraumresonatoren
Authors: Gundermann S. 
Published: July 2007

AbstractIn diesem Beitrag wird ein modifiziertes Verfahren der Mikrowellendiagnostik vorgestellt, das den Einfluß der Instabilitäten des Plasmas auf die Meßgenauigkeit stark herabsetzt.
Power Reflection, Transmission and Absorption Coefficients for a Moving Plasma Slab
Authors: Singh Y. P. , Varma N. L. 
Published: July 2007

AbstractExpressions for power reflection (R), transmission (T) and absorption (A) coefficients for p‐polarized wave for a warm, collisional, magnetized and moving plasma slab (with sharp boundaries and thickness d0) are investigated. The effects of plasma slab velocity (β=v/c), electron density (ωp/ω)2 and plasma temperature (KBT) on reflection (R), transmission (T) and absorption (A) coefficients are discussed numerically. It is observed that for the value β=−0.6, reflection coefficient (R) becomes more than unity, whereas absorption coefficient (A) becomes quite negligible while transmission coefficient (T) shows oscillatory behaviour. The variation with plasma frequency (ωp/ω)2 shows that at lower plasma frequency (ωp/ω)2=0.2 transmission (T) and absorption (A) coefficients are minimum while reflection coefficient (R) is maximum.
Colour Plasma Displays by UV‐Excited Phosphors A Review
Authors: Stern W. 
Published: July 2007

AbstractThough intense work on the development of a full colour flat TV display panel based on gas discharges has produced considerable progress over the last 10 years no practicable technological solutions have been found [1–2]. Of the different approaches the alternating current (ac) discharge has been proved suitable for the alphanumerical and graphical display technique and the direct current (dc) discharge for colour TV panels. To reach such aims as improved optical efficiency, colour gamut and increased life time as well as simpler manufacturing technology and more effective addressing for reducing costs, long‐term basic research in the field of gas discharges and phosphors and the development of special technologies is necessary [3–8]. The present review is an attempt to give a survey of this situation. In Chap. 1 the trends of development, general problems of colour, display types and TV are dealt with, and in Chap. 2 and 3 the literature on dc and ac‐display panels is reviewed.
Interferometric Method for Electronic Density Measurement in a Plasma Focus Device
Authors: Baltog I. , Ganciu M. , Mihut L. , Zambreanu V. , Zoita V. 
Published: July 2007

AbstractA Mach‐Zehnder interferometer with pulsed nitrogen laser used for electronic density studies in the plasma focus device is described. The light pulse duration of 2 ns enables interferometric measurements to be made at any instant during the plasma evolution in a 20 kJ (20 kV) device. A numerical method for interferogram processing and computation of the electronic density is presented. Some preliminary plasma studies are discussed.
Exchange‐Correlation Contribution for the Thermodynamic Functions of a Hydrogen Plasma
Authors: Fromhold‐Treu I. , Kraeft W. D. , Rother T. , Stolzmann W. 
Published: July 2007

AbstractFor a hydrogen model the exchange‐correlation energy is calculated at any degree of degeneracy. The numerical data run into the T=O — RPA values, which were evaluated independently.An equation of state for hydrogen without bound states is compared with HNC‐calculations in the nondegenerate limit. The influence of increasing y=miw/me — values for the agreement with limiting results derived analytically is given in detail.
Investigations of the Current Density in the Cathode Spot of a Vacuum Arc
Authors: Anders S. , Jüttner B. , Pursch H. , Siemroth P. 
Published: July 2007

AbstractA short review is given on the problem of the current density in the cathode spot of a vacuum arc, theoretical models and experimental results are discussed. A new measuring method is presented which is directly related to the current carrying area of the spot. It leads to current densities of 1012 A/m2 at clean surfaces (comparable with results obtained from crater measurements) and 109−1010 A/m2 with contaminated surfaces.
Ionization Waves in Glow Discharges with Non‐Uniform Magnetic Fields
Authors: Maruyama T. , Nishiyama T. , Kitamura H. , Itagaki K. 
Published: July 2007

AbstractThe properties of ionization waves self‐excited in glow discharges with a non‐uniform axial magnetic fields are investigated experimentally. The fundamental frequency remains almost constant over the tube for the variable magnetic fields, while the amplitude decreases with increasing the field. The wavelength becomes longer at the cathode side of the magnetic coil and shorter at the anode side with increasing the local magnetic field. The dependence of the wavelength on the magnetic field is explained by the changes of the axial electric field in the non‐uniform magnetic field.
Numerical Study of the Instability in a Maxwellian Beam‐Plasma System. I. Single Wave Regime
Authors: Bodrow W. , Koch B. P. , Leven R. 
Published: July 2007

AbstractThe characteristic features of the instability development in a Maxwellian beam‐plasma system with one previously excited standing wave is investigated numerically. The unconformity of the simulation results with those predicted by the Single Wave Model is analysed in a small‐cold‐beam limit.
Transport and Turbulence Experiments in Three Regimes of a Magnetized Plasma
Authors: Vogels J. M. M. J. , Schram D. C. 
Published: July 2007

AbstractThe occurrence of turbulence and its influence on plasma viscosity have been investigated. A simple model of turbulence has been obtained by the balance of the growth of the combined Rayleigh‐Taylor and Kelvin‐Helmholtz instability with the damping by friction against the neutrals, by kinetic viscosity and by turbulent viscosity itself. In the experiment, a hollow cathode arc, three regimes can be distinguished: a kinetic, a frictional and a turbulent regime. By variations of the discharge parameters around a suitably chosen operating point, transitions between the three regimes are caused. It appears that the longitudinal drift velocity is also influenced by the turbulence. A dispersion relation for the large scale oscillation of the whole arc has been derived and checked experimentally.
Investigation of Thermochemical Zirconium Cathodes in Nitrogen
Authors: Zhukov M. F. , Pustogarov A. V. , Kucherov Ya. R. , Zavid ei V. I. 
Published: July 2007

AbstractFor arcs with zirconium cathodes in nitrogen, experimental results are presented about changes of material and structure of the cathode, temperature fields, current densities, heat flows, electron work function and erosion rate. The cathode heat regime is described theoretically. In the experiments, the arc current was 50–200 A.
Multiple Scattering Contributions to the Electrical Conductivity of Non‐Ideal Plasmas:. II. Three Particle Scattering
Authors: Blümlein J. 
Published: July 2007

AbstractThree particle effects on the electrical conductivity of hydrogen plasmas are investigated within the Green's function formalism. The transport collision frequency due to e− — H(1s)‐scattering is found to cause a significant lowering of the conductivity isotherms for T ≳ 104 K. This behaviour is similar to that found for caesium plasmas.
Thermosolutal Instability of a Rotating Plasma
Authors: Gupta P. N. , Singh K. V. 
Published: July 2007

AbstractThe thermosolutal instability of a plasma is studied to include the effects of coriolis forces and the finiteness of ion Larmor Radius in the presence of transverse magnetic field. It is observed that the effect of rotation is destabilizing only in a typical case. However, the F. L. R. and stable solute gradient have stabilizing effects on stationary convection irrespective of the presence of coriolis forces.
Boltzmann Equation Analysis of the Electron Gas in CF4 Discharge Plasma
Authors: Mašek K. , Láska L. , D'Agostino R. , Cramarossa F. 
Published: July 2007

AbstractThe electron energy distribution function in CF4 gas discharge was numerically calculated for density reduced electric field E/N = 15 ‐ 300 × 10−17 Vcm2 using the Boltzmann kinetic equation. The momentum transfer and vibrational cross‐sections were derived from available experimental swarm parameters while the cross‐sections for inelastic electron‐molecule collisional processes included were taken from the literature. The two‐term spherical harmonic expansion of the distribution function was used in the calculations.