共查询到20条相似文献,搜索用时 15 毫秒
1.
V. V. Zhakhovskii V. I. Molotkov A. P. Nefedov V. M. Torchinskii A. G. Khrapak V. E. Fortov 《JETP Letters》1997,66(6):419-425
The coexistence of regions of negatively charged macroparticles with substantially different kinetic temperatures in a highly
nonideal dusty plasma in a dc glow discharge has been observed experimentally. An explanation of the observed anomalous heating
of the system of dust particles in a gas-discharge plasma is proposed on the basis of a molecular-dynamics model.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 6, 392–397 (25 September 1997) 相似文献
2.
A. V. Zobnin A. P. Nefedov V. A. Sinel’shchikov V. E. Fortov 《Journal of Experimental and Theoretical Physics》2000,91(3):483-487
Self-consistent molecular-dynamics calculations of the charge of micron-size particles in a low-pressure gas-discharge plasma are performed. It is shown that charge exchange of ions on neutrals starts to affect the charge of dust particles at pressures corresponding to ion mean free paths much greater than the Debye radius. The computational results show that the potential of a particle depends nonmonotonically on the pressure and on the particle size. 相似文献
3.
A. V. Fedoseev G. I. Sukhinin T. S. Ramazanov S. K. Kodanova N. H. Bastykova 《Thermophysics and Aeromechanics》2011,18(4):615-627
The effect of dust particle concentration on gas discharge plasma parameters was studied through development of a self-consistent
kinetic model which is based on solving the Boltzmann equation for the electron distribution function. It was shown that an
increase in the Havnes parameter causes an increase in the average electric field and ion density, as well as a decrease in
the charge of dust particles and electron density in a dust particle cloud. Self-consistent simulations for a wide range of
plasma and dust particle parameters produced several scaling laws: these are laws for dust particle potential and electric
field as a function of dust particle concentration and radius, and the discharge current density. The simulation results demonstrate
that the process of self-consistent accommodation of parameters of dust particles and plasma in condition of particle concentration
growth causes a growth in the number of high-energy electrons in plasma, but not to depletion of electron distribution function. 相似文献
4.
S. N. Antipov É. I. Asinovskiĭ A. V. Kirillin S. A. Maĭorov V. V. Markovets O. F. Petrov V. E. Fortov 《Journal of Experimental and Theoretical Physics》2008,106(4):830-837
A dusty plasma in a dc gas discharge is considered at low (cryogenic) temperatures of the gas. The formation of dusty plasma structures consisting of monodisperse poly(styrene) particles (d = 5.44 μm) in a dc glow discharge is experimentally investigated at cryogenic temperatures in the range from 4.2 to 77 K, and the results obtained are presented. The ion velocity distribution function and the charging of dust particles at cryogenic temperatures are calculated using the molecular dynamics method. The primary attention is focused on the correct inclusion of ion-atom collisions in the analysis. This is essential to the understanding of the main mechanisms of the experimentally observed increase in the density of dust particles with decreasing temperature of the gas in the discharge. 相似文献
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6.
This paper reports on a test using laser Doppler anemometry of the hypothesis that the magnetomechanical effect involves rotation of the plasma of the positive gas-discharge column in an axial magnetic field. This was done by measuring the velocities of the dust macroparticles dropping in a vertical discharge tube. No rotation of the gas was revealed at a sensitivity of 40 cm/s. The rotation of dust particles suspended in striations and in the trap near the narrowed region of the discharge in a magnetic field was observed. The possible connection of this rotation with the magnetomechanical effect is discussed. 相似文献
7.
The size and shape factor distribution of levitating particles is studied by the method of extraction of dust particles from the discharge chamber. Two dust traps existing in a glow discharge in the strata and above the lower wall of the tube near the bend in the current channel are investigated separately. It is found that the size distribution of polydisperse particles of an arbitrary shape is of the bimodal type due to simultaneous levitation of particles with two shape factors. Polydisperse spherical particles of any size exhibit levitation due to the separation of particles over the wall thickness. For identical parameters of the discharge, the size of the particle in neon is slightly larger than in krypton; the particle size in the trap located in a stratum is substantially larger than the particle size in the trap above the wall of the discharge tube. Precision determination of the shape and size of particles makes it possible to estimate the electric field strength for dust traps. It is shown that the glow discharge can be used as a tool for separation of dust particles in a wide range of their sizes. 相似文献
8.
O. S. Vaulina 《Journal of Experimental and Theoretical Physics》2016,122(1):193-202
A brief review of the mechanisms leading to the “anomalous heating” of charged dust particles (macroparticles) in a plasma is presented. Their comparative characteristics are given. An analytical model to estimate the influence of spatial inhomogeneities on the anomalous heating of macroparticles in plasma–dust systems is proposed. 相似文献
9.
V. M. Fat'yanov A. I. Olemskoi V. V. Umrikhin S. I. Barbin V. G. Repin 《Russian Physics Journal》1986,29(6):423-427
The ignition of a gas glow discharge is described as a kinetic transition, for which the charge-carrier concentrations in the plasma region play the role of order parameter, while the external parameter is the field strength in the cathode space. 相似文献
10.
A. V. Filippov M. N. Vasil’ev A. V. Gavrikov A. F. Pal’ O. F. Petrov A. N. Starostin V. E. Fortov 《JETP Letters》2007,86(1):14-19
Charging of dust particles in a plasma with the two-temperature energy distribution of electrons has been studied. It has been shown that the dust-particle potential divided by the electron temperature decreases with increasing electron temperature in the plasma with cold ions. Owing to this behavior, the potential of the dustparticle surface increases with the electron temperature more slowly than the linear function and is lower than the electron temperature (divided by the elementary charge) for T e > 5.5 eV in hydrogen and for T e > 240 eV in argon. The fraction of fast electrons at which these electrons begin to contribute to the charge of dust particles has been determined. It has been shown that the charge of micron particles can reach 106 elementary charges. The effect of the cold and thermal field emission on the charge of dust particles has been analyzed. The possibility of obtaining ultrahigh charges (to 107 elementary charges on dust particles with a radius of 50–100 μm irradiated by a 25-keV 1-mA electron beam has been demonstrated. 相似文献
11.
It is experimentally demonstrated that the electron energy distribution function (EEDF) and electron density in plasma of
a little-studied pulse discharge of a unipolar gas breakdown (UGB) significantly vary in time. The revealed behavior of its
plasma parameters is explained based on the proposed physical model of a UGB discharge. 相似文献
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13.
The dust particle size distribution in a volume glow discharge dusty plasma is studied. Polydisperse quartz particles are
used as a dust component. It is found that a dusty plasma forms in a glow discharge not only in a dust trap but also near
the wall at the bottom of the discharge chamber. Dust objects in the latter region are large: they contain up to 30000 particles.
The size of particles levitating in discharge striations is three times larger than that of particles levitating near the
wall. The idea of using the glow discharge dusty plasma for particle-size fractionation of polydisperse powder is put forward. 相似文献
14.
Magnetically confined argon plasma produced by hollow cathode arc discharge has been studied in different experimental conditions, with discharge current from 10–50 A, vessel argon pressure between 10–3 and 10–4 torr (1 torr=133·32 Pa) and axial magnetic field up to 0·12 T. The plasma density measured by a cylindrical Langmuir probe is found to be 1019 to 4 × 1019 m–3 and the electron temperatureT
e varies between 2·5 and 4·8 eV. When an external axial magnetic field is applied the plasma temperature decreases with the increase in the magnetic field intensity until it reaches a minimum value at 0·075T and then increases with the same rate. This has been interpreted as high frequency waves excitation due to electron beam-plasma interaction, which explains the electron density jumps with the magnetic field intensity. Enhanced plasma transport across the magnetic field is studied and classified as anomalous diffusion. 相似文献
15.
Propagation of both low and high frequency waves in a plasma consisting of electrons, ions, positrons and charged dust particles
have been theoretically studied. The characteristics of dust acoustic wave propagating through the plasma has been analysed
and the dispersion relation deduced is a generalization of that obtained by previous authors. It is found that nonlinear localization
of high frequency electromagnetic field in such a plasma generates magnetic field. This magnetic field is seen to depend on
the temperatures of electrons and positrons and also on their equilibrium density ratio. It is suggested that the present
model would be applicable to find the magnetic field generation in space plasma. 相似文献
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The formation of an out-of-electrode plasma in a high-voltage gas discharge is studied. The occurrence and self-maintenance of a gas discharge and its associated plasma fluxes on the straight portions of electrical field lines are predicted theoretically and confirmed experimentally. It is shown that the focusing of the gas discharge and plasma fluxes is provided by increasing the length of the field line straight portions toward the symmetry axis of a hole in the anode. It is found that, when the discharge power (more specifically, an accelerating voltage applied to the electrodes of the gas-discharge tube) rises, the straight portions of the field lines elongate and concentrate near the symmetry axis of the hole in the anode. Recommendations are given on using the out-of-electrode plasma in surface micro- and nanostructuring. 相似文献
18.
A. P. Nefedov A. G. Khrapak S. A. Khrapak O. F. Petrov A. A. Samaryan 《Journal of Experimental and Theoretical Physics》1997,85(2):272-275
A number of recent experimental investigations of nonideal plasmas containing macroparticles have revealed an anomalous increase
in that part of the kinetic energy of these macroparticles that corresponds to their random motion. In this paper a model
is proposed for the dynamic motion of charged macroparticles that explains this phenomenon.Calculations based on this model
are compared with experimental results.
Zh. éksp. Teor. Fiz. 112, 499–506 (August 1997) 相似文献
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20.
《中国物理 B》2020,(2)
Directional motion of dust particles in a dusty plasma ratcnet is observed experimentally.The dusty plasma ratcnet consists of two concentric gears with asymmetric sawtooth.It is found that the sawtooth number affects the directional motion of dust particles along the saw channel.With the inerease of the sawtooth number,the particle velocity increases firstly and then decreases,and there is an optimum number of the sawtooth which could induce fast rotation of dust particles.The velocities of dust particles change as they are flowing along the saw channel.We also explore the force acting on the dust particle experimentally. 相似文献