Alushta-2012 International Conference-School on Plasma Physics and Controlled Fusion and The Adjoint Workshop
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- DESTRUCTION OF MICROPARTICLES RELATED TO DUSTY PLASMA PROCESSES AND POSSIBLE TECHNOLOGICAL APPLICATIONS
- THE ESTIMATION OF TUNGSTEN AND ODS TUNGSTEN DAMAGES AFTER DENSE PLASMA EXPOSURE ON PF-12 AND PF-1000 V. Shirokova 1) , T. Laas 1)
- PHASE IN AN AXISYMMETRIC CHAMBER
Taras Shevchenko National University, 01033 Kiev, Ukraine;
National technical university “KPI”, Kharkov, Ukraine;
IPP NSC KIPT, 61108 Kharkov, Ukraine
University of Science and Technology Beijing, Beijing 100 083, China
One reason of degradation of plasma facing mirrors (First Mirrors, FM) of optical
methods for plasma diagnostics in ITER will be sputtering by charge exchange atoms (CXA)
resulting in increase of the surface roughness. To avoid degradation of mirror optical
properties, it was suggested [1,2] to fabricate FMs from single crystals. Another promising
possibility way  is the use of materials which have so fine structure that characteristic size
of the surface roughness growing would be much less than the wavelength of the light of
mirror working range. Such materials – amorphous and nano-structural alloys – are now
produced with the size that gives possibility to provide model studies with mirror specimens.
Such investigations were provided in the Institute of Plasma Physics of the National
Science Center KIPT, with an aim to study the behavior of optical properties and the character
of relief developing on the surface of fine-structure materials due to long-term sputtering. The
mirror specimens from amorphous Zr
crystallized at 773 K for
one hour possessed the lowest crystalline particle size (30-70 nm); the grains of a fine-
dispersed alloy Cu-Cr-Zr were of noticeably larger size (200-300 nm), and the grains of a
fine-grain molybdenum and tungsten were even larger (200-400 nm).
All mirror specimens were sputtered by ions of deuterium (Cu-Cr-Zr alloy) or Ar plasmas
up to the ion fluence when the developed relief can be measured by means of profilometry,
interferometry, or scanning electron microscopy (i.e., after sputtering the layer 2.5-4 μm in
thickness). It was found that along with inhomogeneities with the longitudinal scale of a
single grain there appear the inhomogeneities of much larger scale, what can lead to
degradation of optical properties in a much longer wavelengths region.
To clear up the reason of this fact, computer modeling was provided assuming that all
grains are of equal size and the grain of every orientation (12 in total) of crystallographic axis
has some fixed sputtering rate in the angle interval ±15º.
The results demonstrate that the
developing microrelief has not only one-grain-size scale component along the surface but also
the much longer scale inhomogeneities, many times (10-25) exceeding the size of an
1. V.S. Voitsenya, V.G. Konovalov, A.F. Shtan‟ et al. Rev. Sci. Instr., 70 (1999) 790-792.
2. V. Voitsenya, A.E. Costley, V. Bandourko et al. Rev. Sci. Instr., 72 (2001) 475-482.
DESTRUCTION OF MICROPARTICLES RELATED TO DUSTY PLASMA
PROCESSES AND POSSIBLE TECHNOLOGICAL APPLICATIONS
T.I. Morozova, S.I. Kopnin, S.I. Popel
Institute for Dynamics of Geospheres RAS, Moscow, Russia
A method of destruction of microparticles related to dusty plasma processes is discussed. The
method includes the creation of dust particle charges exceeding their limiting values when the
destruction process of the particles starts. The destruction is connected with the fact that the
surface charge of the dust particle creates the electrostatic pressure. When the electrostatic
pressure becomes higher than the strength of the particle, the particle destroys. It is shown
that the destruction of dust particles is possible when the particles are charged positively.
Technological applications of dust particle destruction can be associated with the separation
of nano- and microscale monomineral fractions from polymineral microparticles. For this
purpose one can use modern sources of synchrotron radiation to achieve the limiting positive
values of dust particle charges. This method can be utilized, e.g., for processing of gold ore
from particular deposits.
This work is supported by the Division of Earth Sciences of the Russian Academy of Sciences
(the basic research program No. 5 "Nanoscale particles: conditions of formation, methods of
analysis and recovery from mineral raw").
GROWTH RATES OF FOREST OF SINGLE-WALLED CARBON NANOTUBES IN
PLASMA-ENHANCED CHEMICAL VAPOR DEPOSITION
G. Burmaka, I. Denysenko, N. A. Azarenkov
Department of Physics and Technology, V. N. Karazin Kharkiv National University,
Svobody sq. 4, 61022 Kharkiv, Ukraine
The surface diffusion model is developed, which describes the growth of forest of single-
walled carbon nanotubes in plasma-enhanced chemical vapor deposition. Using the model,
the growth rate of nanotubes, diffusion length and residence time of carbon atoms on
nanotube surfaces are determined, as functions of different external parameters. The model
accounts for nonuniformity in deposition of neutral particles on surface of nanotubes from
discharge chamber, interactions of hydrocarbon molecules and carbon atoms with etching gas,
thermal and ion-induced dissociation of hydrocarbon molecules adsorbed on surface of
nanotubes, decomposition of hydrocarbon ions on nanotube surface, as well as diffusion of
carbon atoms on surface of nanotubes. The growth rates as functions of the carbon nanotube
length are obtained numerically and analytically for different ion and neutral fluxes and
different substrate temperatures.
This work was financially supported by the State Fund for Fundamental Researches of
THE INTERACTION OF DUST PARTICLES IN MAGNETIZED PLASMAS
G.O.Gavrysh, O. Yu. Kravchenko, T.E.Lisitchenko, I. Koval
Taras Shevchenko Kyiv University, Volodymirs‟ka Str. 64, 01601 Kyiv, Ukraine
The problem of the charging of dust particles in plasmas is one of the main tasks to be
studied. Dust particles immersed in plasma acquire charges whose sign and magnitude
strongly affect on the properties of the plasma as well as the properties of the ensemble of
dust particles itself. The charge of the dust grains is of great interest to understand the
behaviour of particles in processing plasmas used for thin-film production, in processes of
growing particles in the gas phase by nucleation and aggregation  as well as for the study
of space plasmas . Recently interest to research of dust structures in a magnetic field has
increased . In this regard, the determination of the charge of dust particles and forces acting
on them in plasmas with magnetic field is important.
The traditional method used to determine the interaction of dust particles with plasmas is
by means of the Orbital Motion Limited (OML) theory. In some articles it was shown that
this theory is not accurate in case high gas pressure, at a strong interaction between particles
and when a relative drift is added [1,2]. Various numerical methods can be employed to solve
this problem. Among them, direct integration of the equation of motion of plasma particles
represents a numerical experiment with significance approaching experiments in laboratory.
In the present paper the process of charging and shielding of dust particles is studied using
computer simulation. The three-dimensional P
M method is applied as the most complete
description of plasma particles motion and interaction with macroscopic dust grains. The
interaction between plasma particles and neutral gas was simulated using Monte-Carlo
method for describing of elementary processes, such as elastic, excitation, ionization, charge
Spherical conductive dust particles were located in nondisturbed low pressure low
temperature plasma in the presence of ion flow at various values of the neutral gas density and
magnetic field. The spatial distributions of plasma particles around dust grains were obtained
at different magnetic fields and ion flow velocities. The formation of the ion clouds behind
dust particles owing to focusing of ion flows was observed. We have demonstrated that the
density of the ion clouds considerably decreases with increasing magnetic field. The
dependence of the ion drag force on neutral gas pressure and magnetic field was investigated.
It was shown that higher ion concentration due to ionization and charge exchange processes
results in growing of the ion drag force. With increasing magnetic field the charge of dust
particles is reduced, which leads to a decrease of the ion drag force.
1. M. Mao, J. Benedikt, A. Consoli, A. Bogaerts, J. Phys. D: Appl. Phys., 41, 225201 (14pp)
2. J. Pavlu, J. Safrankova, Z. Nemecek, I. Richterova, Contrib. Plasma Phys. , 49, 169 – 186
3. L. G. D‟yachkov, O. F. Petrov, V. E. Fortov, Contrib. Plasma Phys. 49, 134 – 147 (2009).
THE ESTIMATION OF TUNGSTEN AND ODS TUNGSTEN DAMAGES AFTER
DENSE PLASMA EXPOSURE ON PF-12 AND PF-1000
, T. Laas
, J. Priimets
, E.V. Demina
, M.D. Prusakova
, M. Scholtz
Institute of Mathematics and Natural Sciences, Tallinn University, Estonia
A. A. Baikov Institute of Metallurgy and Materials Sciences, Moscow, Russia
Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland
Experiments using the plasma focus device PF-12 (Tallinn University) and PF-1000 (Warsaw
Plasma Physics and Laser Microfusion Institute) have been carried out to investigate the
behavior and damage in pure tungsten and ODS tungsten (ODS – oxide dispersed
strengthened). These materials may be suitable candidates for the divertor in a thermonuclear
The pure and ODS tungsten were manufactured by PLANSEE using powder metallurgy
technology. Tungsten was doped with 1% of lanthanum oxide, and was then isostatically
pressed, sintered and rolled. The pure tungsten was made by a similar process. The 20x20 mm
samples were 4 mm thick. Materials were exposed to deuterium plasma for 2 and 8 shots on
PF-12 at distances of 3.5, 6.5, and 10.5 cm, and by 2 shots on PF-1000 at 7-7.5 cm.
Both the original and the irradiated samples were investigated by optical and scanning
electron microscopy, by local X-ray spectroscopic analysis and by X-ray phase-shift analysis.
Also the microstructure, microroughness and microhardness of the samples were investigated.
The analysis by electron microscopy shows that the plasma exposure produced wave-like
structures, a melt-layer and a mesh of microcracks. The wavelength and amplitude of these
structures is practically the same in both materials. The mesh of cracks that appears on the
surface is caused by crystallization of the melt-layer by fast cooling. The density of
microcracks in the ODS tungsten surface increases more gradually with the number of shots
than in the pure tungsten case.
The X-ray phase-shift analysis shows about 5-10% all second phases availability. The lattice
parameter of the ODS tungsten after irradiation was decrease. The second phases are localized
and in good accordance with each other, which have their own physical, chemical and
mechanical properties and influence on the material behavior.
The microhardness has a reduced value near the surface, and at depth oscillations about some
mean value of hardness is observed. In some samples a hardness gradient appears with depth.
The hardness increases in at greater depths, out of the thermal influence zone. The hardness
gradient could either be due to the impact wave caused by the plasma exposure or
alternatively the mechanical processing of the samples.
Taking into consideration that alloys W-%1La
can be more readily machine processed and
that the brittleness of ODS tungsten is lower than W, W-%1La
may be a useful alternative
to pure tungsten in fusion reactor construction.
THE INFLUENCE OF IRRADIATION BY HYDROGEN PLASMA ON THE
STRUCTURE AND PHASE COMPOZITION Ti-Zr-Ni ALLOYS CONTAINING
, I.E. Garkusha
, V.A. Makhlaj
, S.V. Malykhin
, A.T. Pugachоv
Kharkov Polytechnic Institute, NTU, 61002 Kharkov, Ukraine
e-mail: email@example.com, тел.: +38 (057) 7076194
Institute of Plasma Physics of the NSC KIPT, Kharkov, 61108, Ukraine
e-mail: firstname.lastname@example.org, тел.: +38 (057) 3356726
Choice of facing materials and estimation of it response to high heat and particles
fluxes remain one of important issues for realization of fusion reactor project. It all stimulated
research and developed new materials. New radiation-resistant materials are quasi-crystal on
the base Ti-Zr-Ni. They have naturally and noncyclical structure of nanoclusters of fifths
order. Response of quasicrystal to ITER ELM-like heat load did not studied until now. The
results of investigation Ti-Zr-Ni alloy with quasi-crystal phase exposed by ITER ELM like
heat load are presented in this paper.
The samples have been exposed to hydrogen plasma streams produced by the quasi-
steady-state plasma accelerator QSPA Kh-50. The massive sample of Ti41, 5Zr41,5Ni17
obtained after solidification from the melt was used for the plasma load tests. The main
parameters of QSPA plasma streams were as follows: ion impact energy about 0.4 keV, the
maximum plasma pressure 3.2 bars, and the stream diameter about 18 cm. The surface energy
loads measured with a calorimeter were achieved 0.6 MJ/m
(near the tungsten melting
threshold). The plasma pulse shape was approximately triangular, and the pulse duration was
0.25 ms. A surface analysis was carried out with an MMR-4 optical microscope equipped
with a CCD camera and Scanning Electron Microscopy (SEM) of the JEOL JSM-6390 type.
To study a micro-structural evolution of the exposed targets, the X-ray diffraction technique
(XRD) has been used.
It is determined that the initial state is characterized by the presence of crystal-
approximant phase (W-phase) with lattice constant а
= 1.428 nm, (main phase) and the
icosahedral quasicrystalline i-phase with quasicrystalline parameter a
= 0,518 nm. The
irradiation causes the formation of smooth cracks on the surface the plates that are typical for
amorphous materials, and asperities, having the shape of dodecahedrons and triacontahedron.
The content of the icosahedral phase is significantly increased, and the quasicrystalline
parameter decreases to a
= 0,517 nm due to reduced of the content of the most easily
melting element in the alloy - nickel Increasing the number of pulses does not change the
phase composition and structure parameters.
THE ION FLUX AND SHEATH PROPERTIES IN THE AFTERGLOW OF PURE
ARGON AND OF ARGON WITH NEGATIVELY CHARGED DUST PARTICLES
, Igor Denysenko
, Ilija Stefanović
, Jörg Winter
Institute for Experimental Physics II, Ruhr Universität Bochum, 44801 Bochum, Germany
School of Physics and Technology, V. N. Karazin Kharkiv National University Kharkiv,
It has been experimentally observed that the thin film deposition as well as dust particles in
plasma volume influence the discharge properties in radio frequency reactive plasmas, like
electron density, electrode self-bias voltage or Ar* metastable density [1,2]. To improve the
understanding of the processes in the plasma afterglow, the theoretical study of the dynamics
of the ion flux and the sheath width was carried out by using experimental results of time
dependent electron density, electrode self-bias, electron temperature T
, and plasma potential
as input parameters. The experimental data were obtained for a 13.56 MHz low-pressure
capacitively-coupled argon discharge, as explained in . The signal from the RF generator
was modulated by a square-wave signal at frequency of 100 Hz and duty cycle of 50%. The
RF input power was 20 W and the total gas pressure was kept constant at 0.1 mbar. A
hydrocarbon film on the electrodes was deposited by adding ~ 5% of acetylene in chamber for
different time intervals. The growth rate of the deposited film was estimated to be about 1.5
nm/min in the separately performed optical ellipsometry measurements. The ion flux was
deduced from the change of electrode self-bias voltage and its decay time in the plasma
afterglow, similar to the RF biased planar electrostatic probe . It was found theoretically
that the sheath size increases more slowly and the average ion flux to an electrode becomes
larger with growing film thickness. The dependence of the calculated ion flux on the film
deposition time is in a good qualitative agreement with the dependence obtained in
experiment. The effect of dust particles on the ion density at the sheath-plasma boundary was
This work was supported by DGF Project WI 1700/3-1, Research Department “Plasmas
with Complex Interactions” and the Ruhr University Research School funded by Germany's
Excellence Initiative. ID was supported by the Humboldt Foundation and the State Fund for
Fundamental Researches of Ukraine.
 B. Sikimić, I. Stefanović, I. Denysenko, J. Winter 20
ISPC, 24-29 July 2011,
Philadelphia, USA, CPP06.
 I. Stefanović, N. Sadeghi, and J. Winter, J. Phys. D: Appl. Phys. 43 (2010) 152003.
 N. St. J. Braithwaite, J. P. Booth and G. Cunge, Plasma Sources Sci. Technol. 5 (1996)
SIMULATION OF THE EXPIRATION OF THE PLASMA JET WITH A DISPERSED
PHASE IN AN AXISYMMETRIC CHAMBER
O. Yu. Kravchenko, E. V. Kurhanovich, I.S. Marushchak
Taras Shevchenko Kiev University Volodymirs‟ka Str. 64, 01033 Kiev, Ukraine
Plasma flows with disperse phase widespread in plasma and plasma-chemical
technologies. Investigation of the characteristics of these flows is necessary in the processing
of ultrafine powders of metals, in the plasma-chemical receipt of various substances, and
other. Low-temperature plasma is also used in the processes of surface modification coatings.
The aim of this article was to modeling, computation and numerical analysis of the
expiry of plasma jets with dust particles into the vessel, taking into account the interference of
the jet with solid walls of the vessel. The problem was solved in the time-dependent
formulation. The quasi neutral low ionized plasma jet enters with the axis velocity
cylindrical vessel with radius
mm and length
mm through the round nozzle.
At the entrance of the nozzle (diameter of the outlet section of 10 mm) were given plasma
parameters (the total pressure
, total temperature
, total plasma density
parameters of the disperse phase flow (density, drift velocity and temperature of dust
particles). All plasma parameters are constant in this cross-section during a simulation time.
Plasma stream moves in this vessel interacting with contained there neutral gas (which has
some initial parameters) and departs through the side hole.
Plasma jet is described by set of hydrodynamic equations which consist of momentum
equations, continuity equation and energy conservation law for quasineutral plasmas and
disperse phase (dust particles). The model takes into account the interfacial force, thermal
interaction between plasma and dust particles and recombination of the plasma on the surface
of dust particles. The system of equations is solved numerically by the method of large
particles . The calculations were carried out at different parameters of plasma flow
entering in the vessel and continued until a steady flow of plasma. As results, spatial
distributions of the plasma parameters and disperse phase parameters (densities, drift
velocities, temperatures and the plasma pressure) were obtained in various times. The
influence of a disperse phase on parameters of a plasma stream is investigated.
Distribution of dust particles in the chamber is also studied at various parameters of
A.M. Belotserkovskyy, U. M. Davydov Method of major particles in gas-fired dynamics. -
Moscow: Nauka, 1982. - 391 p.
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