2017 жыл

Мақаланың тақырыбы



Журналдың атауы 

Қысқаша аннотация 



Over the barrier electron transfer from a micron sized charged dust particle to an ion in gas discharge plasmas

Bastykova, N.K., Kodanova, S.K., Ramazanov, T.S., Moldabekov, Z.A


Physics of Plasmas, Volume 24, Issue 61,   June 2017, Article number 064501, Q2.

 A simple semiclassical model for the calculation of the electron transfer cross section from the dust particle to the ion is presented. The key ingredient of the model is the transition rate of the electron from the charged dust particle to the ion as a function of the distance between them. Particularly, over the barrier electron transfer from the micron sized spherical dust particle to the surrounding plasma ion is considered. The cross section of this process for the strong dust particle-ion coupling regime, which corresponds to the case of the room temperature gas discharge plasma, is presented. The obtained data were analyzed by comparing them with the ion absorption cross section on the surface of the dust particle. It is found that in the case of micron sized dust particles, more than 15% of ion recombinations with a charged dust particle's electron is due to over the barrier electron transfer. It has been shown that in the considered range of parameters, the cross section of over the barrier electron transfer from the negatively charged dust particle to the ion can be presented in a simple analytical form despite strong nonlinearity of the ion-dust scattering problem. 



Kinetic characteristics of ions in the gas discharge and on the target surface

Maiorov, S.A., Kodanova, S.K., Golyatina, R.I., Ramazanov, T.S.


 Physics of Plasmas, Volume 24, Issue 61, June 2017, Article number 063502, Q2.

The drift velocities of ions in a constant homogeneous electric field are calculated using Monte Carlo simulations for noble-gas and some metal vapors. The ion mobility is analyzed as a function of the field strength and gas temperature. A general approximate formula for the dependence of the drift velocity on the reduced field and gas temperature is derived. The results of calculations of kinetic characteristics of ions crossing the surface of the target are presented. The authors focus on the angular and energy distributions of ions and differences between the distributions of the average volume and the average flow on the surface.



Grain surface heating in cryogenic environment

Ramazanov, T.S., Moldabekov, Zh.A., Muratov, M.M


 Physics of Plasmas, Volume 24, Issue 5, May 1 2017, Article number 050701, Q2.

The surface temperature of the dust particle in cryogenic complex plasmas at gas pressure 0.6-10 Pa is considered. It is shown that at low pressure the dust particle surface temperature is significantly higher than that of the background gas, as a result of which the atom drag force is comparable with the screened Coulomb interaction and even exceeds it for the large-size dust particles. As the gas temperature near the grain surface is a slowly decreasing function of distance with asymptotic 1/r behavior, for correct description of the cryogenic complex plasma at low gas pressure, it is important to include effects related to the dust particle surface temperature.


Scattering cross sections of the particles in the partially ionized dense nonideal plasmas

Shalenov E.O., Dzhumagulova K.N., Ramazanov T.S.


Physics of Plasmas, Volume 24, Issue 11,   January 2017, Article number 012101, Q2.

The electron-atom interaction taking account of dynamic screening is considered in the dense partially ionized plasmas. The phase-function method is used. It is shown that the phase shifts and differential cross sections of the electron scattering on the helium and argon atoms, calculated taking account of dynamic screening, are bigger than those obtained on the basis of the static interaction potential. This can have an influence on macroscopic properties such as transport coefficients


Direct Determination of Dynamic Properties of Coulomb and Yukawa Classical One-Component Plasmas

Arkhipov, Y.V., Askaruly, A., Davletov, A.E., Dubovtsev, D.Y., Donkó, Z., Hartmann, P., Korolov, I., Conde, L., Tkachenko, I.M.


Physical Review Letters, Open access, Volume 119, Issue 4, July 27, 2017. Article number 045001, Q1.

Dynamic characteristics of strongly coupled classical one-component Coulomb and Yukawa plasmas are obtained within the nonperturbative model-free moment approach without any data input from simulations so that the dynamic structure factor (DSF) satisfies the first three nonvanishing sum rules automatically. The DSF, dispersion, decay, sound speed, and other characteristics of the collective modes are determined using exclusively the static structure factor calculated from various theoretical approaches including the hypernetted chain approximation. A good quantitative agreement with molecular dynamics simulation data is achieved.


Effect of thermal annealing on properties of polycrystalline ZnO thin films

Gritsenko, L.V., Abdullin, K.A., Gabdullin, M.T., Kalkozova, Z.K., Kumekov, S.E., Mukash, Z.O., Sazonov, A.Y., Terukov, E.I.


Journal of Crystal Growth, Volume 457, Pages 164 - 1701, January 2017, Q2.

Electrical properties (density, carriers mobility, resistivity), optical absorption and photoluminescence spectra of ZnO, grown by MOCVD and hydrothermal methods, have been investigated depending on the annealing and treatment modes in a hydrogen plasma. It has been shown that the electrical and photoluminescent (PL) properties of ZnO are strongly dependent on gas atmosphere during annealing. The annealing in oxygen atmosphere causes a sharp drop of carrier mobility and films conductivity due to the absorption of oxygen on grain boundaries. The process of ZnO electrical properties recovery by the thermal annealing in inert atmosphere (nitrogen), in oil (2×10−2 mbar) and oil-free (1×10−5 mbar) vacuum has been investigated. The hydrogen plasma treatment influence on the intensity of near-band-gap emission (NBE) has been studied. The effect of annealing and subsequent plasma treatment on PL intensity depends on the gas atmosphere of preliminary thermal annealing.


Solution of the Neumann Problem of Diffraction by a Strip Using the Wiener-Hopf Method: Short-Wave Asymptotic Solutions

Sautbekova, M., Sautbekov, S.


IEEE Transactions on Antennas and Propagation, Volume 65, Issue 9, Pages 4797 - 4802, September 2017, Article number 7990169, Q1.

Plane wave diffraction by a strip is considered by the Wiener-Hopf method and the simple short-wave asymptotic solutions are obtained. The Neumann boundary value problem is reduced to the solutions of the Fredholm integral equations of the second kind, and the exact solution in the form of the sum of infinite series has been found by the method of successive approximations. With the help of the saddle point method, the integral operators are calculated and the asymptotic solutions of system are found. The outcomes are compared with supra known asymptotic solutions taking into account tertiary diffraction. Quarternary diffraction was solved and the calculation methodology for the subsequent diffractions was shown.


Effects of gas temperature, pressure, and discharge power on nucleation time of nano-particles in low pressure C2H2/Ar RF plasmas 

Lin, J., Orazbayev, S., Hénault, M., Lecas, T., Takahashi, K., Boufendi, L.


Journal of Applied Physics, Volume 122, Issue 16, October 28, 2017, Article number 163302, Q1.

The formation of dust particles in low-pressure plasmas is a 3-step process. The first one corresponds to nucleation and growth of nanoparticles by chain reactions between ions and gas molecules, the second one is agglomeration of the nanoparticles to form larger particles, and finally, the particles grow by radical deposition on their surfaces. In this work, the nucleation time for carbon dust particles was studied in low pressure acetylene/argon radio frequency (RF) plasmas. Since the self-bias voltage on a powered electrode was drastically affected by the transition from the nucleation to the agglomeration phases, the nucleation time was measured by observing the self-bias voltage time evolution. The nucleation time increases with the gas temperature and decreases when the gas pressure and the RF power are increased. A kinetic model, involving balance between diffusion and charging times of the nanoparticles as well as the chain reactions, is used to explain the exponential dependence of the nucleation time on the gas temperature. The balance between the times was especially indispensable to get good agreement between the model and the experimental results.