Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions
The structure of MHD-fluctuations in the frequency range 0.5…52 kHz of RF produced plasma was studied in the Uragan-3M torsatron by the use of magnetic probes placed in one of the poloidal cross-sections. Three types of fluctuations with specific spatial (3D) structures were observed. The first type...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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irk-123456789-1221262017-06-28T03:02:49Z Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions Pashnev, V.K. Sorokovoy, E.L. Petrushenya, A.A. Ozherel’ev, F.I. Магнитное удержание The structure of MHD-fluctuations in the frequency range 0.5…52 kHz of RF produced plasma was studied in the Uragan-3M torsatron by the use of magnetic probes placed in one of the poloidal cross-sections. Three types of fluctuations with specific spatial (3D) structures were observed. The first type: when the structure amplitude is changing slowly and the structure rotates as a whole with some frequency. The second type: the structure does not rotate but its amplitude is time varying. The third type is a combination of the first two types: the structure rotates and at the same time its amplitude fluctuates. The correlation was found between the level of fluctuations and the time dependence of plasma energy content before and after transition to regime of better confinement of plasma. С помощью набора магнитных датчиков, размещённых в одном из полоидальных сечений, на установке Ураган-3М исследовалась структура МГД-колебаний плазмы в диапазоне частот 0,5…52 кГц. Наблюдались 3 типа колебаний, имеющих определённую пространственную структуру. Первый тип колебаний, когда амплитуда почти не изменяется со временем, а их структура вращается с определённой частотой. Второй тип – пространственная структура не вращается, но её амплитуда изменяется в определённом диапазоне частот. Третий тип представляет собою объединение первых двух типов – структура вращается, и при этом наблюдаются колебания амплитуды. Была обнаружена связь уровня флуктуаций и временного поведения энергосодержания плазмы перед переходом в режим улучшенного удержания и после него. За допомогою набору магнітних датчиків, розміщених в одному з полоідальних перетинів, на установці Ураган-3М досліджувалася структура МГД-коливань плазми в діапазоні частот 0,5…52 кГц. Спостерігалися 3 типи коливань, що мають певну просторову структуру. Перший тип коливань, коли амплітуда майже не змінюється з часом, а їх структура обертається з певною частотою. Другий тип - просторова структура не обертається, але її амплітуда змінюється в певному діапазоні частот. Третій тип являє собою поєднання перших двох типів структура обертається, і при цьому спостерігаються коливання амплітуди. Був виявлений зв'язок рівня флуктуацій та тимчасової поведінки енергозмісту плазми перед переходом у режим покращеного утримання і після нього. 2017 Article Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions / V.K. Pashnev, E.L. Sorokovoy, A.A. Petrushenya, F.I. Ozherel’ev // Вопросы атомной науки и техники. — 2017. — № 1. — С. 49-53. — Бібліогр.: 17 назв. — англ. 1562-6016 PACS: 52.55.Dy, 52.55.Hc http://dspace.nbuv.gov.ua/handle/123456789/122126 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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Магнитное удержание Магнитное удержание |
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Магнитное удержание Магнитное удержание Pashnev, V.K. Sorokovoy, E.L. Petrushenya, A.A. Ozherel’ev, F.I. Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions Вопросы атомной науки и техники |
| description |
The structure of MHD-fluctuations in the frequency range 0.5…52 kHz of RF produced plasma was studied in the Uragan-3M torsatron by the use of magnetic probes placed in one of the poloidal cross-sections. Three types of fluctuations with specific spatial (3D) structures were observed. The first type: when the structure amplitude is changing slowly and the structure rotates as a whole with some frequency. The second type: the structure does not rotate but its amplitude is time varying. The third type is a combination of the first two types: the structure rotates and at the same time its amplitude fluctuates. The correlation was found between the level of fluctuations and the time dependence of plasma energy content before and after transition to regime of better confinement of plasma. |
| format |
Article |
| author |
Pashnev, V.K. Sorokovoy, E.L. Petrushenya, A.A. Ozherel’ev, F.I. |
| author_facet |
Pashnev, V.K. Sorokovoy, E.L. Petrushenya, A.A. Ozherel’ev, F.I. |
| author_sort |
Pashnev, V.K. |
| title |
Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions |
| title_short |
Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions |
| title_full |
Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions |
| title_fullStr |
Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions |
| title_full_unstemmed |
Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions |
| title_sort |
structure of intensive mhd fluctuations in torsatron in the mode of low frequency collisions |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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2017 |
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Магнитное удержание |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/122126 |
| citation_txt |
Structure of intensive MHD fluctuations in torsatron in the mode of low frequency collisions / V.K. Pashnev, E.L. Sorokovoy, A.A. Petrushenya, F.I. Ozherel’ev // Вопросы атомной науки и техники. — 2017. — № 1. — С. 49-53. — Бібліогр.: 17 назв. — англ. |
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Вопросы атомной науки и техники |
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ISSN 1562-6016. ВАНТ. 2017. №1(107)
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2017, № 1. Series: Plasma Physics (23), p. 49-53. 49
STRUCTURE OF INTENSIVE MHD FLUCTUATIONS IN U-3M
TORSATRON IN THE MODE OF LOW FREQUENCY COLLISIONS
V.K. Pashnev, E.L. Sorokovoy, A.A. Petrushenya, F.I. Ozherel’ev
Institute of Plasma Physics of the NSC KIPT, Kharkov, Ukraine
E-mail: pashnev@kipt.kharkov.ua
The structure of MHD-fluctuations in the frequency range 0.5…52 kHz of RF produced plasma was studied in the
Uragan-3M torsatron by the use of magnetic probes placed in one of the poloidal cross-sections. Three types of
fluctuations with specific spatial (3D) structures were observed. The first type: when the structure amplitude is
changing slowly and the structure rotates as a whole with some frequency. The second type: the structure does not
rotate but its amplitude is time varying. The third type is a combination of the first two types: the structure rotates and
at the same time its amplitude fluctuates. The correlation was found between the level of fluctuations and the time
dependence of plasma energy content before and after transition to regime of better confinement of plasma.
PACS: 52.55.Dy, 52.55.Hc
INTRODUCTION
The results of studies of magnetic field fluctuations
(MF) performed at different toroidal plasma magnetic traps
stimulated theoretical studies in this field. Currently, it was
predicted a great number of instabilities that may cause
MF. Above all, these are drift-Alfven and drift-sound
eigenmodes DAE and DSE [1] or Alfven eigenmodes AE
[2]. Besides, it is possible to have excitation of geodesic
acoustic mode GAM [3], beta-induced Alfven eigenmode
BAE [4], global GAM (GGAM) [5], GAM-like modes
induced by energetic particles GAM – EGAM [6], beta-
induced Alfven-acoustic eigenmodes BAAE [7, 8],
parametric instabilities related to the plasma heating [9],
etc. It is also worth mentioning that heating methods affect
essentially the excitation of drift waves [10].
From the listed above it is clear that characteristics of
plasma instabilities in toroidal traps depend on many
factors and their behavior is rather variable. Thus, the
ways to study these instabilities is to obtain the best
possible information (under given conditions) on the
frequency range, spatial structure of instability, plasma
parameters and methods of its heating.
One of the most convenient methods to diagnose
plasma instabilities accompanied by MF in the confined
volume is to register the MF in the area of plasma
confinement using the set of magnetic probes. In this
case, one can obtain information on frequency range
and spatial structure of these instabilities. As a rule, the
multi-channel system for registration of MF is rather
chip and convenient in operation. The main
disadvantage of such diagnostics is fundamental
inability to determine the area of instability localization
in the plasma volume. Therefore, it is necessary to use
additional measurements by the use of other diagnostics.
The aim of this article is to obtain the information on
instability of plasma produced by RF methods in the l=3
torsatron Uragan-3M (U-3M) device in conditions of
low collisions between plasma particles. The timepoint
selected for detail studies corresponds to the moment
when amplitude of MF reaches the maximum values
and the rate of energy content increase is minimal.
1. EXPERIMENTAL CONDITIONS
Studies at U-3M [11] were performed in RF heating
mode [12]. For plasma production and heating a so-called
frame antenna was used. The frequency of antennae
operation was close to the ion cyclotron frequency
0.8 ci, the working gas – hydrogen. According to
theory, the main mechanism of plasma heating is
Cherenkov damping on electron of the waves excited in
plasma under conditions of Alfven resonance [13]. It is
known that this method of energy transfer to plasma
electrons contributes to distortion of the energy
distribution functions and to occurrence of the conditions
for instability excitation (especially under low collision
frequencies). Besides, considering that waves excited in
plasma have frequency close to the ion cyclotron
frequency, an additional ion heating is possible with
corresponding distortion of the ion distribution function.
When providing these measurements, the mode of low
plasma density ne ≤2•10
18
m
-3
with the maximum density
at magnetic axes ne(0)≈(3…4)•10
18
m
-3
[14] was of
interest. In this mode, the electron temperature (average
over the cross section of the plasma column) and the ion
temperature reached Te ≤ 200 eV and Ti ≤ 300 eV [15],
correspondingly. The effective charge number averaged
over the cross section of the plasma column was Z≈1
[15]. Magnetic field on geometric axis of plasma
configuration is B0≈0.72 Т. This mode is interesting
because electrons and ions are in a “banana” regime,
what was confirmed by registration of the so-called
bootstrap current [16]. It is known that the future
thermonuclear reactor will operate in similar mode and
thus, our studies can be useful.
2. EXPERIMENTAL RESULTS
In one cross section of plasma column a set of 15
magnetic probes (coils) registered the poloidal component
of magnetic field were installed at a radius bpr=16.8 cm
(Fig. 1). The coils with diameter 6 mm and length 16 mm
were placed inside the electrostatic screen and have
sensitivity NS=180 coils•cm
2
(N is a number of turns in
the coil, S is the area of the coil cross-section). Each coil
with the connection cable (length 20 m) allowed to register
50 ISSN 1562-6016. ВАНТ. 2017. №1(107)
the variation of poloidal magnetic field with frequency up
to 70 kHz. Signals from probes were integrated using 16-
channel electron integrator. The constant of integration
varied in the range of τ=5∙(10
-8
…10
-5
)
s.
Fig. 1. The poloidal cross-section of the torus showing
positions of helical coils, magnetic probes #1…15 and
vacuum magnetic surfaces
The time interval, where the amplitude of fluctuation
reaches maximal value 3.0
~
B G, was selected for detail
study of the structure of fluctuations in the plasma
confinement volume. In this moment, an essential decrease
of growth rate of plasma energy content was observed
what was recorded by a diamagnetic loop (Fig. 2, upper
curve). As seen, there is a rapid decrease of fluctuation
amplitude at the end of the time interval studied (time
moment 35.3 ms is indicated by the dotted line in Fig. 2)
with corresponding increase of plasma energy content
Fig. 2. Time behavior of the plasma energy and its
derivative, and the signal from one probe (the lowest
time profile). The dotted line shows the moment of a
sharp rise of the plasma energy content
Fig. 2 shows that the recorded signals (the lowest
oscillograms) are non-stationary and represent a set of
consecutive fluctuation groups, where one or several
oscillations with variable amplitudes and frequencies do
occur. Since it is incorrect in such a case to speak about
local frequency, we will use the term “frequency
bandwidth”. Correspondingly, the obtained raw
implementations were divided into 5 frequency ranges
to process the obtained set of signals, such that:
δf1=0.5…5 kHz, δf2=5…11 kHz, δf3=11…20 kHz,
δf4=20…31.5 kHz, δf5=31.5…52 kHz. The sampled
signals were then implemented in a certain frequency
range by the use of band-pass filters. In this way the
distributions of signal amplitudes along the whole set of
probes were obtained for any given time moment for
any of this frequency range. The obtained data were
represented as a set of harmonics with various poloidal
wave numbers m=0; 1; 2; 3 (Fig. 3,b). The higher
harmonics with m>3 were not considered because the
accuracy of their identification using 15 probes is rather
small in conditions of the experiment. The amplitudes
of this spatial harmonic were recorded for the
measurement surface (bpr=16.8 cm) together with their
phase shifts relatively to the previous point in time. The
knowledge of harmonic amplitudes on the measurement
surface allows to recalculate the fluctuation amplitude
for the radius within the confinement volume according
to the formula described in [17]. As was shown in that
paper, the decrease of the magnetic field for each
poloidal harmonics is described by Bessel functions,
which in the first approximation can be written as:
(bpr/b)
m+1
, where m is the number of poloidal harmonics.
The re-calculation was done for the radius b=8.4 cm
(inside of confinement volume) with taking into account
that the averaged radius of plasma column is a =10 cm.
It is obvious that there is a dramatic underestimation of
the role of fluctuations with higher poloidal wave
numbers in comparison with the level of fluctuations
inside plasma column. Therefore below in the text, for
the purpose of information objectivity, only those data
re-calculated for the inside plasma volume will be
further discussed.
Fig. 3. Polar distribution of signals amplitude from the
magnetic probes at the time point of 35.014 msec (a)
and mode spectrum of this distribution along poloidal
wave numbers (b)
The results of recorded signals processed are shown
in Fig. 4 for the frequency range δf2=5…11 kHz. In this
figure, for each spatial harmonic the time variation of
the phase of this structure φ (regarding external plane
point of the facility) and its amplitude are shown. The
amplitude is shown as 2~
B .
As it is clear from Fig. 4, the phase of the structure
m=0 possesses the values “0” and “π” what corresponds
to the sign change of the fluctuation amplitude. Based
on the fluctuation period one can estimate the frequency
bandwidth where the fluctuations are realized. For
example, according to Fig. 4, in the time interval
t=35.1…35.3 ms there is only one full fluctuation in the
frequency range 6.5…7.3 kHz. From the physical point
of view, the structure with m=0 can be either
fluctuations of plasma current or fluctuations of the
confining magnetic field.
a
b
ISSN 1562-6016. ВАНТ. 2017. №1(107) 51
Fig. 4. Dependences of amplitude and phase in the
frequency bandwidth of δf2=5…11 kHz for poloidal
wave numbers m=0; 1; 2; 3
By analyzing all available experimental data we
conclude that there are three types of fluctuations
registered in this experiment. The first one, when the
structure with the given wave number is standing or
slowly rotates; its amplitude changes with the recorded
frequency. The fluctuations of this type are observed
permanently. The second one is the structure rotating
with a certain frequency and the amplitude slightly
varying with time. Most often, its rotating velocity is
not constant in time. Typically, the fluctuation
frequency of the “standing on the spot” (SOS) structure is
close to the rotating velocity of the second type structure.
If we consider that SOS structure can quickly turn to a
certain angle when its amplitude approaches zero, then it
seems that this SOS structure stimulates the rotation. The
third type is a combination of the first two types.
Fig. 5. Dependence on the recorded frequency
bandwidth of the maximal amplitude module of
fluctuations for spatial structures with different poloidal
wave numbers m. The light bars determine the standing
structures and the shaded bars show the rotating
structure. The rotation direction towards electron
rotation in the magnetic field is taken as positive
Fig. 6. Fluctuation amplitudes of four spatial structures
with m=0; 1; 2; 3 in the frequency range of 6…8 kHz on
the measurement surface
Fig. 5 shows the dependence on the recorded
frequency bandwidth of the modules for maximum
fluctuation amplitudes of spatial structures with m=0; 1;
2; 3. The positive and negative amplitude modules
correspond to different directions of structure rotation
(shaded bars). The positive values correspond to
rotation in the direction of electron Larmor rotation. The
light bars define the maximum amplitude of the SOS
structure. The column width shows the approximate
frequency range of the recorded fluctuations.
The analysis of experimental data shows that MF
exists in a rather narrow frequency ranges that are
52 ISSN 1562-6016. ВАНТ. 2017. №1(107)
common for spatial structures with different poloidal
wave numbers. MF were recorded in the frequency
ranges: 1.5…2 kHz, 6…8 kHz, 13…16 kHz,
20…27 kHz, 35…43 kHz (Fig. 5).
For structures with m=1 and m=2 there observed a
rotation in different directions in the frequency range
1.5…2 kHz but we failed to determine the value of the
rotating structure. The maximum values of MF of the
SOS structures are observed for m=2 and 3.
In the frequency range 6…8 kHz there are fluctuations
of both the SOS structures with m=0; 1; 2; 3 and the
“rotating” structures with m=1; 2; 3 (see Fig. 4). It should
be noted that all fluctuations of the SOS structures are
interrelated. In other words, their frequencies and phases
are close to each other and represent a common
perturbation for all spatial structures (Fig. 6). The
amplitude of fluctuations inside the plasma confinement
volume increases with increasing the poloidal mode
number (see Fig. 5). The structures with m=2 have the
maximal amplitude of the rotating structure wherein the
rotation rate increases with increasing the fluctuation
amplitude of the SOS structure, and coincides with its
frequency at maximal amplitude.
For the fluctuations in the range of 13…16 kHz the
rotation is present only for the structures with m=1 and
m=2. The SOS structures are correlated with each
other (except for m=0) and have maximal amplitude
for structures with m=2 and m=3. The amplitudes of
the rotating structures are less than the amplitudes of
the SOS structures.
Fluctuations of the SOS structures in the bandwidth
of δf4=20…31.5 kHz are in the range of 20…22 kHz
except for the structure with m=2, the bandwidth of
which is 20…27 kHz. Only the structure with m=2
rotates with the frequency frot=25…26 kHz, wherein
the amplitude of the rotating structure exceeds
essentially the amplitude of the SOS structure.
In the bandwidth δf5=31.5…52 kHz the fluctuations
of the SOS structures are in the range 40…43 kHz except
for the structure with m=2 where there are fluctuations in
the bandwidth 35…37 kHz and the rotation frequency is
frot≈37 kHz. The amplitude of the “rotating” structure in
the maximum is higher than of the SOS structures. The
fluctuations of the SOS structure with m=3 have the
maximum amplitude.
As can be seen from fig. 5, the rotation of the structures
with m=1; 2; 3 for the frequency bandwidths
δf1=0.5..5 kHz and δf2=5…11 kHz is taking place. The
question marks in this figure indicate that the rotation of
the structure is qualitatively seen, but the rotation
amplitude cannot be identified. Also, it is clear that for
m=1 and m=3 the frequencies of “rotating” structures differ
essentially from the frequencies of the SOS structures.
Probably we observe the initial stage of the structure
rotation, which is breaking away for some reason, and does
not reach the maximum of the frequency.
CONCLUSIONS
The performed studies showed that in the low collision
frequency plasma produced by RF power in the torsatron
U-3M the quite narrow-band fluctuations are arising in 5
frequency ranges: 1.5…2 kHz, 6…8 kHz, 13…16 kHz,
20…27 kHz, 35…43 kHz.
The spatial structure of these fluctuations is
characterized by poloidal wave numbers m=0; 1; 2; 3.
There are three types of fluctuations:
- the standing or slow rotating structures, which
amplitude changes within certain frequency range;
- the rotating structure which amplitude changes
slightly and the maximum rotation frequency is close to
the fluctuation frequency of a “standing” structure;
- the third type is a combination of the first two types:
the structure rotates and at the same time its amplitude
fluctuates.
The standing structures can represent a complex
configuration (fluctuations with different wave numbers
correlated with each other).
The rotating structures can have different poloidal
numbers, however, their maximal amplitudes have
structures with m=2. The direction of rotation of these
structures coincides predominantly with the direction of
electron Larmor rotation.
The standing structures have maximum fluctuation
amplitude at the poloidal wave number m=3 and its
magnitude is up to B
~
≈0.3 G in the plasma confinement
volume.
REFERENCES
1. Ya.I. Kolesnichenko, V.V. Lutsenko, A. Weller, et al.
Drift-sound and drift-Alfven eigenmodes in toroidal
plasmas // Europhysics Letters. 2009, v. 85(2), p. 25004.
2. Ya.I. Kolesnichenko, A. Konies, V.V. Lutsenko, et al.
Affinity and difference between energetic-ion-driven
instabilities in 2D and 3D toroidal systems // Plasma
Phys. Control. Fusion. 2011, v. 53(2), p. 024007.
3. N. Winsor, J.L. Johnson, J.M. Dawson. Geodesic
acoustic waves in hydromagnetic systems // Physics of
Fluids. 1968, v. 11(11), p. 2448.
4. M.S. Chu, J.M. Greene, L.L. Lao, et al. A numerical
study of the high-n shear Alfven spectrum gap and the
high-n gap mode // Phys. Fluids B. 1992, v. 4, p. 3713.
5. H.L. Berk, C.J. Boswell, D. Borba, et al. Explanation
of the JET n≤0 chirping mode // Nucl. Fusion. 2006,
v. 46(10), p. S888.
6. R. Nazikian, G.Y. Fu, M.E. Austin, et al. Intense
geodesic acousticlike modes driven by suprathermal ions
in a tokamak plasma // Phys. Rev. Lett. 2008, v. 101(18),
p. 185001.
7. G.T.A. Huysmans, W. Kerner, D. Borba, et al.
Modeling the excitation of global Alfven modes by an
external antenna in the Joint European Torus (JET) //
Phys. Plasmas. 1995, v. 2(5), p. 1605.
8. N.N. Gorelenkov, M.A. Van Zeeland, H.L. Berk, et al.
Beta-induced Alfven-acoustic eigenmodes in National
Spherical Torus Experiment and DIII-D driven by beam
ions // Phys. Plasmas. 2009, v. 16(5), p. 056107.
9. K.N. Stepanov. Nonlinear parametric phenomena in
plasma during radio frequency heating in the ion
cyclotron frequency range // Plasma Phys. Control.
Fusion. 1996, v. 38(12A), p. A13.
10. W.W. Heidbrink. Basic physics of Alfven instabilities
driven by energetic particles in toroidally confined
plasmas // Phys. Plasmas. 2008, v. 5(5), p. 055501.
11. V.V. Chechkin, I.P. Fomin, L.I. Grigor`eva, et al.
Density behaviour and particle losses in RF discharge
ISSN 1562-6016. ВАНТ. 2017. №1(107) 53
plasmas of the URAGAN-3M torsatron // Nucl. Fusion.
1996, v. 36(2), p. 133.
12. V.V. Chechkin, L.I. Grigor'eva, R.O. Pavlichenko, et
al. Characteristic properties of the frame-antenna-
produced RF discharge evolution in the Uragan-3M
torsatron // Plasma Physics Reports. 2014, v. 40(8),
p. 601.
13. A.V. Longinov, K.N. Stepanov. High-Frequency
Plasma Heating / Ed. A.G. Litvak. New York: “AIP”,
1992, p. 93-238.
14. V.K. Pashnev, I.K. Tarasov, D.A. Sitnikov, et al. The
problem of plasma density increasing in the U-3M
torsatron after RF heating termination // Problems of
Atomic Science and Technology. Ser. “Plasma Physics”.
2013, № 1, p. 15.
15. V.K. Pashnev, E.L. Sorokovoy, A.A. Petrushenya, et
al. Dynamics of the main plasma parameters during
spontaneous transition into the mode of improved
confinement in torsatron U-3M // Problems of Atomic
Science and Technology. Ser. “Plasma Physics”. 2010,
№ 6, p. 24.
16. V.K. Pashnev, E.L. Sorokovoy. Appearance of
neoclassical effects in plasma behavior in torsatron
Uragan-3M // Problems of Atomic Science and
Technology. Ser. “Plasma Physics”. 2008, № 6, p. 31.
17. V.D. Shafranov. Voprosy Teorii Plazmy / Еdited by
M.A. Leontovich. Moscow: “Atomizdat”, 1963, v. 2,
p. 51 (in Russian).
Article received 12.12.2016
СТРУКТУРА ИНТЕНСИВНЫХ МГД-ФЛУКТУАЦИЙ В ТОРСАТРОНЕ У-3М В РЕЖИМЕ РЕДКИХ
СТОЛКНОВЕНИЙ
В.К. Пашнев, Э.Л. Сороковой, А.А. Петрушеня, Ф.И. Ожерельев
С помощью набора магнитных датчиков, размещённых в одном из полоидальных сечений, на установке
Ураган-3М исследовалась структура МГД-колебаний плазмы в диапазоне частот 0,5…52 кГц. Наблюдались 3
типа колебаний, имеющих определённую пространственную структуру. Первый тип колебаний, когда
амплитуда почти не изменяется со временем, а их структура вращается с определённой частотой. Второй тип –
пространственная структура не вращается, но её амплитуда изменяется в определённом диапазоне частот.
Третий тип представляет собою объединение первых двух типов – структура вращается, и при этом
наблюдаются колебания амплитуды. Была обнаружена связь уровня флуктуаций и временного поведения
энергосодержания плазмы перед переходом в режим улучшенного удержания и после него.
СТРУКТУРА ІНТЕНСИВНИХ МГД-ФЛУКТУАЦІЙ В ТОРСАТРОНІ У-3М У РЕЖИМІ РІДКИХ
ЗІТКНЕНЬ
В.К. Пашнєв, Е.Л. Сороковий, А.А. Петрушеня, Ф.І. Ожерельєв
За допомогою набору магнітних датчиків, розміщених в одному з полоідальних перетинів, на установці
Ураган-3М досліджувалася структура МГД-коливань плазми в діапазоні частот 0,5…52 кГц. Спостерігалися 3
типи коливань, що мають певну просторову структуру. Перший тип коливань, коли амплітуда майже не
змінюється з часом, а їх структура обертається з певною частотою. Другий тип просторова структура не
обертається, але її амплітуда змінюється в певному діапазоні частот. Третій тип являє собою поєднання
перших двох типів структура обертається, і при цьому спостерігаються коливання амплітуди. Був виявлений
зв'язок рівня флуктуацій та тимчасової поведінки енергозмісту плазми перед переходом у режим покращеного
утримання і після нього.
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