bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the Basic Process Parameters on the Ion/Atom Arrival Rate Ratio during Magnetron Sputter Deposition of Thin Carbon Films
Authors: Petrov I. , Orlinov V. , Ivanov I. , Kourtev J. 
Published: July 2007

AbstractThe behaviour of the ratio of the argon ion flux and the sputtered atom flux to the substrate with the variation of the basic process parameters was studied in a planar magnetron sputtering system. Finding ways to control this ratio is important with respect to carrying out ion‐assisted thin film growth by magnetron sputtering under well‐defined conditions. Combined deposition rate measurements and plasma probe measurements were carried out in order to determine the ion/atom arrival rate ratio. In addition calculations of the neutral atom flux were performed on the basis of a simple model and the results compared with the measured values. A considerable change in the values of the ion/atom arrival rate ratio with the variation of the argon pressure and the discharge power was found under operating conditions, at which the back diffusion of the sputtered material is pronounced. The distribution of the ion flux over the substrate surface was found to become more homogeneous with the increase of the working pressure or the target‐to‐substrate distance.
Plasma Processes in Activated Thin Film Deposition
Authors: Lunk A. , Schmidt M. 
Published: July 2007

AbstractThis paper deals with plasma aspects in physical and chemical vapour deposition processes. A systematic representation of deposition methods is given and possibilities of plasma diagnostic are summerized. Characteristic parameters of electron kinetics (mean free paths, collision frequencies, energy distribution functions) and rate equations for calculation of particle densities are discussed for a plasma in plasma activated physical vapour deposition device. Theoretical results are compared with measurements (Te, Ne, Ez) in the plasma of a TiNx‐deposition device with hollow cathode arc evaporator. Mechanism of plasma polymerisation is discussed. Results of experimental investigations of the plasma in an Ar‐hexamethyldisiloxane D.C. low pressure glow discharge are presented and compared with results of modelling of this plasma taking into account direct‐, stepwise‐ and Penning‐ionization. The necessivity of knowledge of reactive cross sections for understanding of plasma assisted thin film formation processes is accentuated.
Nonlocal Heat flux in the Scrape‐Off Layer of a High‐Temperature Plasma
Authors: Chodura R. 
Published: July 2007

AbstractA Fokker‐Planck particle code is used to simulate the energy transport in a magnetized plasma at conditions where the mean free‐path length of heat‐flux‐carrying electrons is comparable with or larger than the electron temperature gradient length. Heat fluxes are calculated for the case of a plasma between two reflecting plates at different temperatures and for the case of one reflecting and one absorbing plate.
Monte Carlo Modelling of Impurities: Comparison with Some Jet and Dite Experiments
Authors: Stangeby P. C. , Farrell C. 
Published: July 2007

AbstractA two‐dimensional Monte Carlo impurity atom/ion code, LIM, was used to model a number of DITE and JET experiments including (a) the ratio of charge states collected by the Matthews probe in DITE, (b) the net erosion pattern on the 1986 JET limiters, and (c) radial and toroidal CI, CII, CIII cloud shapes in the vicinity of DITE limiters.
Study of an Underexpanded Plasma Jet II. Diagnostics with Microwaves
Authors: Anders A. , Ershov A. P. , Isaev K. 
Published: July 2007

AbstractThe properties of the plasma of an underexpanded jet in air were examined by optical and by probe methods as described in a previous paper (Contrib. Plasma Phys. 27 (1987) 203). The jet was produced by an erosion plasmatron with xenon‐filling operating in a single‐pulse regime. Now, independent measurements of the space‐time development of the electron density by microwave interferometry are described. The results of cut‐off and phase shift measurements are in agreement with those obtained by probe diagnostics.
Effects of Hall Currents and Gyroviscosity on the Instability of a Self‐Gravitating Stratified Plasma
Authors: Mehta Vijay , Bhatia P. K. 
Published: July 2007

AbstractThe instability in a horizontal layer of a partially ionized self gravitating plasma has been studied to include simultaneously the effects of Hall currents, viscosity and finiteness of Larmor radius (FLR). The ambient magnetic field is assumed to be uniform and vertical. Proper solutions have been obtained through the variational methods for a semi‐infinite plasma in which the density has an exponential gradient along the vertical. The dispersion relation obtained has been solved numerically and it is found that the growth rate of unstable perturbations decreases with the effects of viscosity, neutral gas friction and FLR. The influence of effects of viscosity, neutral gas friction and FLR are consequently stabilizing. It is found that the Hall currents have a destabilizing influence as the growth rate is found to increase with this effect.
Analytical Models of Free‐Burning Electric Arcs
Authors: Kozlov P. V. , Engelsht V. S. , Zhajnakov A. 
Published: July 2007

AbstractTwo‐dimensional electric arc model based on the solution of the energy equation by means of variables separation method in curve‐line orthogonal coordinates, associated with electrical arc characteristics, is suggested. Quite accurate solution of MGD‐equations complete system for the arc with radial current spreading out of the top nozzle of the conic electrode is produced. Influence of electrode geometry on arc column characteristics in some particular cases has been analysed.
Langmuir Probe Characterization of a RF Discharge Excited in Ar/C2F3Cl Mixtures during Plasma Deposition Processes
Authors: Špatenka P. , Šícha M. 
Published: July 2007

AbstractThe apparatus for measurements of probe characteristic and its second derivative during plasma assisted thin film deposition is described. To avoid the probe surface contamination an impulse method combined with ion bombardment of the probe surface was used. Experimental evidence of the effectiveness of this method in the discharge fed with Ar/C2F3Cl mixtures is given. Measurements of the second derivative of the probe current have indicated an electron distribution different from the Maxwellian. Negative ions have been found in the discharge, the concentration of which has been estimated to be at most by one order of magnitude higher than the electron density.
Excitation Temperature Measurement of Ar + N2 RF Plasma by Spectroscopic Method
Authors: Joshi N. K. , Thiagarajan T. K. , Rohatgi V. K. , Ashtamoorthy T. S. 
Published: July 2007

AbstractThe mixed gas (Ar + N2) plasma has been generated by a 6 KW, 10.3 MHz radio frequency oscillator. The flame got extinguished if N2 exceeded more than 20% of Ar. The Boltzmann plot using spectral intensities of Ar I and NI lines in the wavelength range 4000–4510 Å have been used to determine the excitation temperature. The results show that excitation equilibrium between two species exist since the temperatures are found to be nearly same for both species.
The Influence of Neutral Particle Sources on the Dynamics of Tokamak Plasmas. II. Particle Dynamics and Induced Electromagnetic Fields
Authors: Bachmann P. , Sünder D. , Tskhakaya D. D. 
Published: July 2007

AbstractIn part I of our paper [1] a kinetic theory of the influence of neutral particle sources on the dynamics of tokamak plasmas has been developed and the general solution of this problem has been given for an arbitrary source function. By the use of these results we calculate in this part II the particle's distribution function for different simple source functions. In the case of recycling perpendicular to the limiter surface we derive analytical expressions for the charge density, the induced electric potential and the anomaleous electron density flux transverse to the magnetic field.
Magnetogravitational Instability of a Thermally Conducting Rotating Plasma through a Porous Medium
Authors: Chhajlani R. K. , Vyas M. K. 
Published: July 2007

AbstractMagnetogravitational instability of an infinite homogeneous, viscous, thermally conducting, rotating plasma flowing through a porous medium has been studied with the help of relevant linearized perturbation equations, using the method of normal mode analysis. Rotation is taken parallel and perpendicular to the magnetic field for both, the longitudinal and the transverse modes of propagation. The joint influence of the various parameters do not, essentially, change the Jeans' criterion but modifies the same. The adiabatic velocity of sound is being replaced by the isothermal one due to the thermal conductivity. Porosity reduces the effects of both, the magnetic field and the rotation, in the transverse mode of propagation, whereas the rotation is effective only along the magnetic field for an inviscid plasma. The viscosity removes the effect of rotation in the transverse mode of propagation.
Spectral Emissivity of Dense Hydrogen Plasma at Balmer Series Limit
Authors: Ershov‐Pavlov E. A. , Krat'Ko L. E. , Chubrik N. I. , Shimanovitch V. D. 
Published: July 2007

AbstractSpectral emissivity of hydrogen plasma with a nonideality parameter γ = 0.1 ÷ 0.15 has been measured in the wavelength region of 341 ÷ 513 mm using a 6A‐current stabilized d.c. arc at pressures up to 30 bars as the plasma generator. A comparison of the measured data and the data calculated using the Unsöld and Inglis‐Teller formulas shows no evident discrepancies that might be attributed to the additional influence of plasma microfields on the continuum emissivity of hydrogen at Balmer series limit for the range of electron concentrations and temperatures up to 1018 cm−3 and 14500 K, respectively.
Formation of Clusters in Dense Alkali Plasmas
Authors: Redmer R. , Röpke G. 
Published: July 2007

AbstractThe composition of dense alkali plasmas is calculated accounting for the formation of neutral clusters as well as positively and negatively charged molecular ions. The resulting values for the critical point of the liquid‐gas phase transition are in better agreement with experimental data as previous theoretical work. The simultaneous occurence of the metal‐nonmetal transition is discussed by means of the elctrical conductivity.
OCP Dynamical Structure Factor and the Plasma Dispersion: Method of Moments
Authors: Adamjan S. V. , Meyer T. , Tkachenko I. M. 
Published: July 2007

AbstractThe molecular dynamics data of HANSEN, MCDONALD and POLLOCK [1] on the dynamical properties of the classical one‐component plasma (OCP) are compared with the results based on an approximation formula for the dielectric function [2] satisfying all known sum rules and exact relations using HNC plasma static properties [3].
Transport Coefficients for Nonideal Hydrogen and Cesium Plasmas
Authors: Reinholz H. , Redmer R. , Tamme D. 
Published: July 2007

AbstractThe transport coefficients of a nonideal plasma are expressed by equilibrium correlation functions within the ZUBAREV approach. Besides the treatment of the different interactions in a partially ionized plasma, this approach allows also for the currents of the heavy particles ions and atoms. Furthermore, the influence of an arbitrary mass ratio on the transport coefficients is investigated. Explicit results are shown for H (n= 1017… 1020cm−3,T= (1…3) · 104K) and Cs plasma (n= 1015…1021cm−3,T= (3…10) · 103K).
Dynamical Screening and the dc Conductivity in a Fully Ionized Plasma
Authors: Morales F. , Kilimann M. K. , Redmer R. , Schlanges M. , Bialas F. 
Published: July 2007

AbstractA kinetic equation with a composed collision term (Boltzmann + Lenard‐Balescu‐Landau) is solved numerically. Dynamical screening is taken into account in the e‐e‐scattering. The conductivity of a fully ionized H‐plasma was calculated. In comparison to static screening dynamical screening tends to lower the conductivity.
Determination of the Electrical Conductivity of a Plasma on the Basis of the Coulomb cut‐off Potential Model
Authors: Mihajlov A. A. , Djordjević D. , Popović M. M. , Meyer T. , Luft M. , Kraeft W. D. 
Published: July 2007

AbstractOn the basis of the Coulomb cut‐off potential model [2, 3] electrical conductivity calculations for a H‐Plasma are carried out in a temperature and density range 8000 K ⩽ T ⩽ 50000 K and 1018 cm−3 ⩽ ne ⩽ 1024 cm−3. The electron‐ion scattering is included by the semiclassical result given in [2, 3], whereas the influence of the electron‐electron scattering is included by the well known Spitzer‐factor. The electron‐neutral interaction is modelled by a polarization potential [8] in Born‐approximation. The results for the electron‐ion interaction show a dependence only on the parameter Γc = e2kBT/γrc, whereas the electron‐neutral interaction has a more complicated temperature dependence.
Determination of Parameters of the Arc Plasma of Electrodynamic Macro‐Particle Accelerator by the Method of Simulation of Surface Energy Losses
Authors: Djuric Z. , Mihajlov A. A. 
Published: July 2007

AbstractIn the paper we have presented the model method of calculating electrical arc parameters in the macroparticles' electrodynamic accelerator at the given rail width and the given width between them. The method is based on energy losses simulation at the arc's boundary surfaces and is a modification of the one‐dimensional version of Powell and Batteh's method. It has been shown that the proposed method is adequate for operative use and that it enables the determination of both macroscopic arc parameters · acceleration, length, electroconductivity, mean temperature and density of particles etc., as well as local arc plasma parameters. The values of these parameters are determined by numerical solutions of the self‐consistent system of mangetic‐hydro‐dynamic, material and thermodynamic equations, at the arc's given mass and muzzle voltage between rails. It has also been shown that the proposed method allows the comparison of one‐, two‐ and three‐dimensional arc approximations. In the present paper we have used the method assuming that arc plasma is at most doubly ionized and produced exclusively by copper atoms.
1‐D 1‐Fluid Sol Modeling with Finite Elements
Authors: Zanino R. , Schneider W. 
Published: July 2007

AbstractWe present here the numerical solution of a 1‐D (along the magnetic field) 1‐Fluid time dependent set of SOL model equations (particle, momentum and energy balances) by means of finite element (FE) discretization of the space coordinate. The results are compared with those of the SOLID finite difference (FD) code [W. Schneider, et al., J. Nucl. Mater. 121, 178 (1984)] and good agreement is found between the two. This shows the potential of the FE to work also in the presence of strong convection, as is the case near the divertor plate or limiter ‐ a feature which if confirmed in the 2‐D case will make them particularly attractive for SOL simulation.
The Application of Langmuir Probes to the Measurements in Flowing Afterglow Plasma
Authors: Sicha M. , Sun Zu Cham , Glosik J. , Tichy M. 
Published: July 2007

AbstractLangmuir probe measurements in argon flowing afterglow are presented together with probe data analyses. The charged particles density is evaluated from the electron probe current at the space potential and from the saturated positive ion current. The latter is analysed using the method by Zakrzewski and Kopiczynski [15, 16] and both results are compared against each other. A satisfactory agreement almost within the estimated experimental error range suggests that the method [15, 16] brings a reasonable description of a positive ion collection by a Langmuir probe.
Dispersion Relations for Drift‐Alfvén and Drift‐Acoustic Waves in Arbitrary Directions
Authors: Venema M. , Suchy K. 
Published: July 2007

AbstractA dispersion equation for low‐frequency waves in a fully ionized plasma with slowly varying density and magnetic field is derived from the two‐fluid equations. The solutions are discussed in several limiting cases. Phase‐velocity and refractive index surfaces are presented for the fast and slow magneto‐acoustic waves and for the shear‐Alfvén wave, influenced by the inhomogeneity drifts.
KInetic Description of the Positive Column for Medium Knudsen‐Numbers
Authors: Wallschläger H. 
Published: July 2007

AbstractWe analyze the influence of collisions on a plasma column with cylindrical symmetry in the pressure regime between the collision‐dominated and the free‐fall case. A model is investigated which can handle arbitrary contributions from ion‐neutral‐collisions. One finds an analytic solution for the ion‐distribution‐function which depends functionally on the potential. This electrical potential is calculated numerically — with consideration of the space‐charge‐layer near the wall — and selfconsistently from the Poisson‐equation. From the calculation of the ion‐distribution‐function, of density, flux and temperature of the ions as well as of the potential variation, we discuss the influence of the model parameters. The results are compared with corresponding hydrodynamic calculations.
Linear and Nonlinear Magnetic Electron Drift Waves in a Nonuniform Strong Magnetic Field
Authors: Stenflo L. , Shukla P. K. , Murtaza G. , Yu M. Y. 
Published: July 2007

AbstractLinear and nonlinear propagation of magnetic electron drift vortex waves in a nonuniform magnetic field is investigated by means of a generalized adiabatic law which takes into account the effect of strong fields and reduces in the appropriate limits to several well known energy conservation equations in a collisionless plasma. In the linear limit, an instability is shown to exist, whereas in the nonlinear regime, steady‐state dipole vortices associated with the electron drift vortex waves may appear. The anomalous electron energy transport associated with the unstable magnetic electron drift vortex waves is investigated by means of a quasilinear theory.
Nonlinear Pulse Propagation in Unmagnetized Plasmas
Authors: Bhakta J. C. 
Published: July 2007

AbstractEvolution of pulses for unmagnetized plasmas have been considered. By using Rayleigh‐Ritz optimization method based on trial functions ordinary differential equations for the pulse parameters have been derived. It is found that the character of the pulse parameters depends on the initial wavenumber chirp.
A Group Theoretic Approach to the Magnetohydrodynamic Equations and Group Invariant Solutions
Authors: Ludu A. , Iovitu‐Popescu I. 
Published: July 2007

AbstractThe application of transformation group methods to a system of nonlinear partial differential equations, representing an incompressible M H D plasma, is shown. The structure of the symmetry group is investigated and a theorem of existence of the solutions of the system of equations is given. Some illustrative analytical invariant solutions and their differential invariants will be presented.
Nonlinear Wavepackets in Kelvin‐Helmholtz Instability in Hydromagnetics
Authors: Deysikder S. , Das K. P. 
Published: July 2007

AbstractThe instability of small but finite amplitude waves propagating at the interface of two layers of highly conducting incompressible fluids in relative motion in presence of external uniform magnetic field is studied. Using the method of multiple scales nonlinear evolution equations are derived for both linearly stable and marginally stable cases. It is found that in the linearly stable case both the modes are modulationally unstable. The nonlinear cut‐off wavenumbers are determined.
Spark Temperature Enhancement by Adding a Parallel Capacitor in High Voltage Circuit
Authors: Pavlov M. , Djurović S. , Kobilarov R. , Vujičić B. 
Published: July 2007

AbstractTemperature of sparks produced by automotive ignition systems have been measured spectro‐scopically. It is shown that by adding a capacitor of the order of 10 to 100 pF, temperature of the arc phase of a spark can be considerably increased.
A Simple Model of Diffuse Vacuum arc Plasmas
Authors: Hantzsche E. 
Published: July 2007

AbstractThe diffuse expanding plasma of low‐current vacuum arcs is composed of and characterized by an almost thermal electron gas and an ion beam with high kinetic energy. It is described theoretically with a two‐fluid hydrodynamic model. By application of thorough simplifications (such as isothermal conditions, constant composition, one‐dimensional treatment) an analytical solution is found in the form of asymptotic power series of the plasma parameters. This solution is used to analyse the plasma ion acceleration, resulting in the statement that the three forces acting on ions (i.e. the electric field, the ion pressure gradient, the electron‐ion friction) are of comparable importance, contributing to the total ion energy roughly 20%, 35%, and 45%, respectively (in case of Cu vapour arcs). As to the electric field and Ohm's law the solution reveals that the potential is falling towards the anode and that the diffusion current exceeds the opposite conduction current with the consequence of a negative resistance of the arc plasma. Finally, the approximations of the solution, limitations of the validity and possible extensions of the model are shortly discussed.
Radiation Efficiency and Kinetic Calculations for the Positive Column in Hg/Ar Mixtures. I. Thg Variation
Authors: Kreher J. , Bartolomäs G. , Wilhelm J. , Stern W. 
Published: July 2007

AbstractProperties of the positive column of low pressure Hg/Ar discharge have been investigated from the point of view of its application in fluorescent lamps. The results obtained are based on experimental methods to determine both UV resonance radiation fluxes of the 63 P1 and 61P1 Hg levels and to measure the electron distribution function by probes; in addition a kinetic model is applied for the theoretical interpretation of the experimental results and to give a deeper insight into the particle and energy budget. In the present first part of the paper the effects of recently determined τeff‐values on radiation, net collision rates, power transfer and the electron energy distribution for extended parameter values are investigated especially in dependence on mercury partial pressure.
Plasma Diagnostics in a Hollow Cathode arc Evaporation System During TinX‐Deposition
Authors: Lunk A. , Basner R. 
Published: July 2007

AbstractDuring the deposition of hard titaniumnitrid films the plasma conditions were investigated with a movable Langmuir‐probe in axial and radial directions systematically. The deposition took place in a hollow cathode arc evaporation equipment (HCAE). We measured the electron energy distribution function (EEDF) or electron temperature, the plasma potential, the concentration of the ions and electrons, the density of the neutral particles and the evaporation characteristics. A twodimensional model was developed to describe the plasma under the conditions of the plasma activated vapour deposition (PAPVD). The model uses the first and second momentums of the Boltzmann equation (hydrodynamical description). Under experimentally realized geometrical conditions the electron temperatures are calculated by this model and are compared with experimental results.The measured second derivative of the probe characteristic (measured by the sample and hold method) showed, that the EEDF is a Maxwellian one. The measured electron temperatures are in the range of 2.5–4 eV in accordance with calculated values.
Nonsymmetrical Electromagnetic Waves in Partially Plasma — Filled Waveguide
Authors: Ivanov S. T. , Alexov E. G. , Malinov P. N. 
Published: July 2007

AbstractThe dispersion of nonsymmetrical electromagnetic waves in waveguide, partially filled with plasma, is studied numerically and experimentally. An external d.c. coaxial magnetic field is applied to the waveguide. The dispersion equation of these waves is obtained, and it is solved numerically for the experimental conditions. Results are obtained, which show coupling of the waveguide HEl1‐modes with the family of the high‐frequency plasma HEln‐modes. The numerical dispersion curves are experimentally examined, and the influence of the magnetic field and the plasma density is studied.