Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics
A possibility of determining some parameters (density, collision rate, magnetic field strength, mass-and-ion charge) of the plasma being in a magnetic field is under consideration. Peculiarities in the change of probing wave refraction and absorption values depending on the plasma parameters are inv...
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| Date: | 2014 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2014
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| Cite this: | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics / Yu.V. Kovtun, I.B. Pinos, A.I. Skibenko , E.I. Skibenko // Вопросы атомной науки и техники. — 2014. — № 6. — С. 179-182. — Бібліогр.: 10 назв. — англ. |
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| author | Kovtun, Yu.V. Pinos, I.B. Skibenko, A.I. Skibenko, E.I. |
| author_facet | Kovtun, Yu.V. Pinos, I.B. Skibenko, A.I. Skibenko, E.I. |
| citation_txt | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics / Yu.V. Kovtun, I.B. Pinos, A.I. Skibenko , E.I. Skibenko // Вопросы атомной науки и техники. — 2014. — № 6. — С. 179-182. — Бібліогр.: 10 назв. — англ. |
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| description | A possibility of determining some parameters (density, collision rate, magnetic field strength, mass-and-ion charge) of the plasma being in a magnetic field is under consideration. Peculiarities in the change of probing wave refraction and absorption values depending on the plasma parameters are investigated. Appreciation is made of the possibility for plasma diagnostics by means of probing using low-frequency electromagnetic waves with frequencies of ion-cyclotron range.
Рассмотрена возможность определения некоторых параметров плазмы (плотности, частоты соударений, напряженности магнитного поля, массы и заряда ионов), находящейся в магнитном поле, за счет исследования особенностей изменения показателей преломления и поглощения зондирующей волны от этих параметров. Оценена возможность диагностики плазмы с помощью зондирования низкочастотными электромагнитными волнами с частотами порядка ионно-циклотронных.
Розглянута можливість визначення деяких параметрів плазми (густини, частоти зіткнень, напруженості магнітного поля, маси і заряду іонів), що знаходиться в магнітному полі, за рахунок дослідження особливостей зміни показників заломлення і поглинання зондуючої хвилі від цих параметрів. Оцінена можливість діагностики плазми за допомогою зондування низькочастотними електромагнітними хвилями з частотами порядку іонно-циклотроних.
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ISSN 1562-6016. ВАНТ. 2014. №6(94)
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2014, №6. Series: Plasma Physics (20), p. 179-182. 179
INVESTIGATION ON THE POSSIBILITY OF DETERMINING PLASMA
PARAMETERS BY THE METHOD OF LOW-FREQUENCY
DIAGNOSTICS
Yu.V. Kovtun, I.B. Pinos, A.I. Skibenko , E.I. Skibenko
NSC “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
E-mail: Ykovtun@kipt.kharkov.ua
A possibility of determining some parameters (density, collision rate, magnetic field strength, mass-and-ion
charge) of the plasma being in a magnetic field is under consideration. Peculiarities in the change of probing wave
refraction and absorption values depending on the plasma parameters are investigated. Appreciation is made of the
possibility for plasma diagnostics by means of probing using low-frequency electromagnetic waves with frequencies
of ion-cyclotron range.
PACS: 52.70.-m; 52.70.Gw
INTRODUCTION
The use of high-frequency electromagnetic waves
for plasma diagnostics is possible only with fulfillment
of the following conditions: the probing frequency ω
significantly exceeds the ion-cyclotron frequency ωci
and the electron-collision rate νei , the electron velocity
is significantly lower than the phase wave velocity and
the plasma parameters are changing slightly on the wave
length. In this case the ion influence on the wave propa-
gation can be neglected. The development of investiga-
tions on plasma physics, on plasma-technology direc-
tions and the urgency of solving the problem of con-
trolled thermonuclear fusion have leaded to the building
of large-scale facilities with longitudinal and transverse
dimensions of several meters and more. Thus the diag-
nostic measurements of plasma parameters with low-
frequency (LF) waves become possible [11]. The plas-
ma wave propagation in this range has been investigated
thoroughly [2,3] in connection with the problem of cre-
ating high frequencies (HF) and heating fusion plasma
[4-8]. Also, in the monograph [9] the plasma propaga-
tion in the isotropic and magnetoactive plasma wave-
guides has been investigated.
Moreover, similar global problems arise and are
solved in the allied fields of science and technique. For
example, in the ecology [10] it is important to know an
elemental composition of samples from various soils to
determine their destination and different conditions of
their maintenance. Currently for this purpose one uses
laser technologies and methods. However, other tech-
niques are to be applied to solve the problems of soil
controlling and decontamination from pollution with
different metals including heavy metals and their com-
pounds. Therefore, taking into account [1-9] and other
physical and engineering developments [10], the study
of low-frequency waves to be used in the plasma diag-
nostics (LFD) seems possible and expedient. New op-
portunities of low-frequency plasma diagnostics can be
of interest also for the investigation of multicomponent
plasma parameters in a magnetic field, in particular, in
the presence of ions with large-masses and high charge
values.
1. POSSIBILITY OF DETERMINING
PLASMA PARAMETERS
The distribution of low-frequency electromagnetic
waves (having the frequencies of ion-cyclotron waves)
moving in the plasma along the magnetic field is de-
scribed, with taking into account the ion motion [1,2],
by the following equations:
, (1)
, (2)
, (3)
, (4)
, (5)
where μ is the refraction coefficient, χ is the absorption
coefficient , ωp is the plasma frequency, ωce and ωci are
the electron and cyclotron frequencies, A and B are the
components of a medium complex dielectric permittivi-
ty. A similar set of equations can be written for the case
of the plasma with Maxwell distribution [2] when the
initial plasma state is equilibrium, i.e. is determined by
the velocity Maxwell particle distribution.
Taking into account that ,
, , mi = amp, the values
μ and χ are determined by the plasma density, magnetic
field intensity, collision rate, ion mass and its charge.
Therefore, let us consider the possibility of determining
the above mentioned parameters due to the investigation
of peculiarities in the variation of refraction and absorp-
tion coefficients depending on these parameters. Thus,
the possibilities of the diagnostics with the use of low-
frequency electromagnetic wave probing will be esti-
mated.
Fig. 1 represents the frequency dependences of the re-
fraction coefficient μ and absorption coefficient χ for dif-
ferent plasma density values (from 1·10
12
to 1·10
13
cm
-3
)
mailto:Ykovtun@kipt.kharkov.ua
180 ISSN 1562-6016. ВАНТ. 2014. №6(94)
with the magnetic field intensity H = 2 kOe, collision
rate s
-1
and ion mass a = mi/m = 1. The de-
pendences are of a resonance character. The resonance
values of frequencies for μ and χ and, consequently, the
resonance width are dependent on the plasma parame-
ters. Also note, that the refraction coefficient μ is deter-
mined by phase measurements and the absorption coef-
ficient χ is determined by amplitude measurements. As
the amplitude measurements are simpler in the experi-
mental realization and subsequent processing. in the
following consideration we will operate only with the
absorption coefficient χ. The resonant frequency chang-
es with the magnetic field, ion mass and its charge
changing. At the same time, the plasma density and col-
lision rate variation do not lead to the resonant frequen-
cy change and influence only on the amplitude and the
width of the resonance curve. So, the parameters H, a,
z can be determined by measuring the resonant frequen-
cy; the density is determined by measuring the ampli-
tude of absorption coefficient χ; the collision rate – by
measuring the resonance curve width at its half-width
maximum amplitude. In addition, it should be taken into
account that the possibility of these measurements de-
pends on the wave attenuation and wave length in the
plasma. Analysis of the refraction and absorption coeffi-
cients as a function of the frequency at different density
values in the range of N = 10
12
…10
13
cm
-3
shows that the
resonant region in the curves (see Fig. 1) narrows with
collision rate decreasing, and the resonant frequency
does not depends on the plasma density and frequency
rate.
An important aspect for realization of the plasma di-
agnostics technique offered is the fact that during reso-
nance the wave undergoes a strong attenuation. The at-
tenuation estimations give the following results. For ex-
ample, if ν = 10
9
s
-1
the attenuation coefficient in the cho-
sen density range reaches the values of F =
0.67…0.21 Np/cm or the amplitude decrease per cm A0/A
= 1.96…1.21; for ν = 10
7
s
-1
F = 6.7…2.1 Np/cm. There-
fore it is more convenient to measure the attenuation at
the frequency below the resonant one. So, when the
frequency decreases, starting from the resonant region,
by 340 HGz at ν = 10
9
s
-1
and by 30 kHz at ν = 10
7
s
-1
the wave attenuation in the plasma density range from
10
12
to 10
13
cm
-3
is equal to 0.179…0.565 Np/cm and
0.077…0.24 Np/cm redpectively.
2. DESCRIPTION OF TECHNIQUES FOR
LOW-FREQUENCY PLASMA
DIAGNOSTICS
As is shown above, the dependences of characteristic
parameters μ and χ of the low-frequency wave, in the
region of ion-cyclotron frequencies, passing through the
plasma are of a resonance character. To determine the
multicomponent plasma parameters N, H, a, z, ν it is rea-
sonable to use the dependences of wave parameters (μ, χ)
on the resonant frequency. Consequently, it is necessary
to know the values of the resonant frequency, resonance
width at its half-amplitude. In this case the plasma prob-
ing is carried out by the frequency-modulated waves.
The density is determined by measuring the χ ampli-
tude from the relation χ = f(ω) (see Fig. 1) in the reso-
nance point (region). The density is calculated from the
quadratic equation such as , where
the coefficients a1, b1, c1 are determined from the calcu-
lated relations χ = f(ω) for different plasma density val-
ues given in Fig. 1. For example, in the range of densi-
ties N = 10
11
…10
12
cm
-3
at the collision rate ν ≈ 10
6
s
-1
the plasma density is determined via the absorption co-
efficient using the equation N = 1.9·10
4
·χ
2
. Thus, for the
range of N = 10
11
…10
12
cm
-3
and the value ν ≈ 10
7
s
-1
we obtain the following relation N = 2.06·10
6
·χ
2
.
The collision rate in the plasma is determined by the
width of the resonance curves of the dependence χ =
f(ω) using the formula ν=a2Δω+b2 where the coeffi-
cients a2 and b2 are determined from the calculated de-
pendences (Fig. 2). For example, when a=1,
ν=(2.68·10
2
Δω+4.46·10
-6
) s
-1
.
Fig. 1. Frequency dependences of the refraction coeffi-
cient μ and absorption coefficient χ at different density
values ( Н = 2000 Oe, ν=10
9
s
-1
, a=1, Z=1)
Fig. 2. Frequency dependences of the absorption coeffi-
cient χ on the collision rates. (N =10
13
cm
-3
, ν=10
9
s
-1
,
a=1, H=2000 Oe, Z=1)
The magnetic field intensity H in the plasma column
region (or the change of H in this region under the
plasma gas-kinetic pressure NkT) can be determined by
the resonance frequency value using the dependence
χ = f(ω) given in Fig. 3 and the equation
H=(1.04·10
4
ωres-18.6) Oe. The dependence H=f(N, ν)
is rather weak. The technique offered for determining
the magnetic field intensity (or its changing) in the
plasma column region can be of a great practical im-
portance for the plasma with a sufficient high value
.
Knowledge of the multicomponent plasma ion mass
a is of great importance for determining plasma compo-
ISSN 1562-6016. ВАНТ. 2014. №6(94) 181
sition and for solving some applied problems, in par-
ticular, upon the substance separation into elements and
mass groups with application of magnetoplasma tech-
niques. In this study we have found that the relative
multicomponent plasma ion mass a is determined by the
resonance frequency and width Δωres. the resonance
curve at its half-width maximum amplitude, which can
be determined from the dependences χ = f(ω) (see
Fig. 1). At H=2000 Oe, N= 10
13
cm
-3
, ν=10
9
s
-1
, z=1,
a=2,54·10
4
Δω+64. Fig. 4 presents the frequency de-
pendences of the relation χ = f(ω) at different values of
the relative ion mass in the range of a=12–56 with
H=2000 Oe, N= 10
13
cm
-3
, ν=10
9
s
-1
.
Fig. 3. Frequency dependences of the absorption coeffi-
cient χ at different values of the magnetic field
(N =10
12
cm
-3
, ν=10
7
s
-1
, a=1)
Fig. 4. Frequency dependences of the absorption coeffi-
cient χ at different values a (N = 10
13
сm
-3
, ν=10
9
s
-1
,
H=2000 Oe, Z=1)
The charge z of the multicomponent plasma ions is
determined also from the dependence χ = f(ω) (Fig. 5).
The plasma parameters N and v do not exert significant
influence on the behavior of this dependence and on the
value z.
Fig. 5. Frequency dependences of the absorption coeffi-
cient χ at z=1, 2, 3 (N =10
13
cm
-3
, ν=10
9
s
-1
, a=40)
Since for determining some of the multicomponent
plasma parameters, such as collision rate, ion mass, it is
necessary to know the width ωres of the resonance curve
at its maximum half-width amplitude, in our study we
have determined the dependences of the resonance
curve width χ = f(ω) on the collision rate (Fig. 6).
Fig. 6. Frequency dependences of the resonance curve
width of the absorption coefficient χ on the collision
rate, 1 – a =1; 2 – a =40 (N =10
13
cm
-3
, H=2000 Oe,
Z=1)
CONCLUSIONS
A possibility of determining the multicomponent
plasma parameters in a magnetic field by the method of
low-frequency electromagnetic wave probing is ana-
lyzed. It is established that the frequency dependences
of the refraction and absorption coefficients of the elec-
tromagnetic waves are of a resonance character. Using
the LF waves for multicomponent plasma probing along
the magnetic field it is possible to determine the plasma
ion component density, collision rate, local magnetic
field intensity or its change, find the presence of ions
having different mass and charge. For this the probing
wave frequency should be modulated and the main cor-
responding resonance characteristics (for example, ab-
sorption coefficient), in particular, the resonance fre-
quency and resonance curve width at its half-width
maximum amplitude, should be measured.
Computer simulation was applied to obtain the reso-
nance dynamics by changing the above-mentioned
plasma parameters (shown in the plots of Figs. 1-5. The
curves of Figs. 1-5 were used to derive the simplified
analytical expressions for calculation of plasma parame-
ters with taken initial conditions.
So, the use of LF waves for the magnetoactive plas-
ma probing enlarges the arsenal of equipment and tech-
niques for plasma diagnostics with electromagnetic
waves.
REFERENCES
1. V.L. Ginzburg // Propagation of Electromagnetic
Waves in Plasma. Oxford, New York: “Pergamon
Press”. 1970, p. 615.
2. A.I. Akhiezer. Electrodynamics of plasma. M.
“Nauka”, 1974, p. 719 (in Russian).
182 ISSN 1562-6016. ВАНТ. 2014. №6(94)
3. K.N. Stepanov. Plasma physics and problems of con-
trolled thermonuclear fusion. К.:“Naukova
dumka”,1965, № 4, p. 48-59.
4. N.I. Nazarov, A.I. Ermakov, A.S. Lobko,
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physics and problems of controlled thermonuclear fu-
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6. O.M. Shvets’, V.F. Tarasenko, S.S. Ovchinnikov,
V.T. Tolok. Plasma physics and problems of controlled
thermonuclear fusion. К.:“Naukova dumka”, 1963,
№ 3, p. 117-124.
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al. // Problems of Atomic Science and Technology. Se-
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8. I. Lysoivan, V.E. Moiseenko, V.V. Plyusnin, et al. //
Fusion Engineering and Design. 1995, v. 26, № 1-4,
p. 185-190.
9. A.N. Kondratenko // Plasma waveguides.
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Article received 23.09.2014
ИССЛЕДОВАНИЕ ВОЗМОЖНОСТИ ОПРЕДЕЛЕНИЯ ПАРАМЕТРОВ ПЛАЗМЫ С ПОМОЩЬЮ
МЕТОДОВ НИЗКОЧАСТОТНОЙ ДИАГНОСТИКИ
Ю.В. Ковтун, И.Б. Пинос, А.И. Скибенко, Е.И. Скибенко
Рассмотрена возможность определения некоторых параметров плазмы (плотности, частоты соударений,
напряженности магнитного поля, массы и заряда ионов), находящейся в магнитном поле, за счет исследова-
ния особенностей изменения показателей преломления и поглощения зондирующей волны от этих парамет-
ров. Оценена возможность диагностики плазмы с помощью зондирования низкочастотными электромагнит-
ными волнами с частотами порядка ионно-циклотронных.
ДОСЛІДЖЕННЯ МОЖЛИВОСТІ ВИЗНАЧЕННЯ ПАРАМЕТРІВ ПЛАЗМИ ЗА ДОПОМОГОЮ
МЕТОДІВ НИЗЬКОЧАСТОТНОЇ ДІАГНОСТИКИ
Ю.В. Ковтун, I.Б. Пінос, А.І. Скибенко, Є.І. Скібенко
Розглянута можливість визначення деяких параметрів плазми (густини, частоти зіткнень, напруженості
магнітного поля, маси і заряду іонів), що знаходиться в магнітному полі, за рахунок дослідження особливос-
тей зміни показників заломлення і поглинання зондуючої хвилі від цих параметрів. Оцінена можливість діа-
гностики плазми за допомогою зондування низькочастотними електромагнітними хвилями з частотами по-
рядку іонно-циклотроних.
|
| id | nasplib_isofts_kiev_ua-123456789-81935 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T16:46:29Z |
| publishDate | 2014 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Kovtun, Yu.V. Pinos, I.B. Skibenko, A.I. Skibenko, E.I. 2015-05-22T17:33:03Z 2015-05-22T17:33:03Z 2014 Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics / Yu.V. Kovtun, I.B. Pinos, A.I. Skibenko , E.I. Skibenko // Вопросы атомной науки и техники. — 2014. — № 6. — С. 179-182. — Бібліогр.: 10 назв. — англ. 1562-6016 PACS: 52.70.-m; 52.70.Gw https://nasplib.isofts.kiev.ua/handle/123456789/81935 A possibility of determining some parameters (density, collision rate, magnetic field strength, mass-and-ion charge) of the plasma being in a magnetic field is under consideration. Peculiarities in the change of probing wave refraction and absorption values depending on the plasma parameters are investigated. Appreciation is made of the possibility for plasma diagnostics by means of probing using low-frequency electromagnetic waves with frequencies of ion-cyclotron range. Рассмотрена возможность определения некоторых параметров плазмы (плотности, частоты соударений, напряженности магнитного поля, массы и заряда ионов), находящейся в магнитном поле, за счет исследования особенностей изменения показателей преломления и поглощения зондирующей волны от этих параметров. Оценена возможность диагностики плазмы с помощью зондирования низкочастотными электромагнитными волнами с частотами порядка ионно-циклотронных. Розглянута можливість визначення деяких параметрів плазми (густини, частоти зіткнень, напруженості магнітного поля, маси і заряду іонів), що знаходиться в магнітному полі, за рахунок дослідження особливостей зміни показників заломлення і поглинання зондуючої хвилі від цих параметрів. Оцінена можливість діагностики плазми за допомогою зондування низькочастотними електромагнітними хвилями з частотами порядку іонно-циклотроних. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Низкотемпературная плазма и плазменные технологии Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics Исследование возможности определения параметров плазмы с помощью методов низкочастотной диагностики Дослідження можливості визначення параметрів плазми за допомогою методів низькочастотної діагностики Article published earlier |
| spellingShingle | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics Kovtun, Yu.V. Pinos, I.B. Skibenko, A.I. Skibenko, E.I. Низкотемпературная плазма и плазменные технологии |
| title | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics |
| title_alt | Исследование возможности определения параметров плазмы с помощью методов низкочастотной диагностики Дослідження можливості визначення параметрів плазми за допомогою методів низькочастотної діагностики |
| title_full | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics |
| title_fullStr | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics |
| title_full_unstemmed | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics |
| title_short | Investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics |
| title_sort | investigation on the possibility of determining plasma parameters by the method of low-frequency diagnostics |
| topic | Низкотемпературная плазма и плазменные технологии |
| topic_facet | Низкотемпературная плазма и плазменные технологии |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81935 |
| work_keys_str_mv | AT kovtunyuv investigationonthepossibilityofdeterminingplasmaparametersbythemethodoflowfrequencydiagnostics AT pinosib investigationonthepossibilityofdeterminingplasmaparametersbythemethodoflowfrequencydiagnostics AT skibenkoai investigationonthepossibilityofdeterminingplasmaparametersbythemethodoflowfrequencydiagnostics AT skibenkoei investigationonthepossibilityofdeterminingplasmaparametersbythemethodoflowfrequencydiagnostics AT kovtunyuv issledovanievozmožnostiopredeleniâparametrovplazmyspomoŝʹûmetodovnizkočastotnoidiagnostiki AT pinosib issledovanievozmožnostiopredeleniâparametrovplazmyspomoŝʹûmetodovnizkočastotnoidiagnostiki AT skibenkoai issledovanievozmožnostiopredeleniâparametrovplazmyspomoŝʹûmetodovnizkočastotnoidiagnostiki AT skibenkoei issledovanievozmožnostiopredeleniâparametrovplazmyspomoŝʹûmetodovnizkočastotnoidiagnostiki AT kovtunyuv doslídžennâmožlivostíviznačennâparametrívplazmizadopomogoûmetodívnizʹkočastotnoídíagnostiki AT pinosib doslídžennâmožlivostíviznačennâparametrívplazmizadopomogoûmetodívnizʹkočastotnoídíagnostiki AT skibenkoai doslídžennâmožlivostíviznačennâparametrívplazmizadopomogoûmetodívnizʹkočastotnoídíagnostiki AT skibenkoei doslídžennâmožlivostíviznačennâparametrívplazmizadopomogoûmetodívnizʹkočastotnoídíagnostiki |