Studies of light liner compression dynamics in plasma focus
The study is devoted to the investigation of plasma focus systems as a driver for magnetic compression of liners. The experiments on the comparative analyse of the foam and multiwired liners compression were done on the Filippov-type plasma focus facility PF-3. The compression of the light (linear m...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2003
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nasplib_isofts_kiev_ua-123456789-1105472025-02-09T15:50:50Z Studies of light liner compression dynamics in plasma focus Дослідження динаміки стиснення легких лайнерів в плазмовому фокусі Исследование динамики сжатия легких лайнеров в плазменном фокусе Karakin, M.A. Khautiev, E.Yu. Krauz, V.I. Mokeev, A.N. Myalton, V.V. Smirnov, V.P. Plasma dynamics and plasma-wall interaction The study is devoted to the investigation of plasma focus systems as a driver for magnetic compression of liners. The experiments on the comparative analyse of the foam and multiwired liners compression were done on the Filippov-type plasma focus facility PF-3. The compression of the light (linear mass 0.3-0.6 mg/cm) liners with velocity (2-3).10⁶ cm/s was obtained. It is shown that under conditions of considerable radiation fluxes at the usage of strongly-radiating working gases a preliminary heating of the target can be attained. This results in acceleration of the transition of initially – condensed substance into plasma state, that assists in overcoming “cool start” problem. Робота присвячена дослідженню плазмового фокусу (ПФ) в ролі драйверa для магнітного обтиснення лайнерів. Проведено експерименти з порівняльного аналізу стиснення пінних й багатодротових лайнерів на установці типу Філіппова ПФ-3. Отримано стиснення лайнерів з погонною масою 0.3-0.6 мг/см зі швидкостями (2-3).10⁶ см/с при амплітуді розрядного струму 2 МА. Показано, що в умовах значних радіаційних потоків при використанні сильновипромінюючих робочих газів може бути здійснений попередній нагрів мішені. Це призводить до прискорення переходу первісно конденсованої речовини у плазмовий стан, що дає змогу подолати проблему «холодного старту». Работа посвящена исследованию плазменного фокуса (ПФ) в качестве драйвера для магнитного обжатия лайнеров. Проведены эксперименты по сравнительному анализу сжатия пенных и многопроволочных лайнеров на установке типа Филиппова ПФ-3. Получено сжатие лайнеров с погонной массой 0.3-0.6 мг/см со скоростями (2-3).10⁶ см/с при амплитуде разрядного тока 2 МА. Показано, что в условиях значительных радиационных потоков при использовании сильноизлучающих рабочих газов может быть осуществлен предварительный нагрев мишени. Это приводит к ускорению перехода первоначально конденсированного вещества в плазменное состояние, что способствует преодолению проблемы “холодного старта ”. We are grateful to S.L.Nedoseev and S.F.Medovschikov (TRINITI) for liners manufacturing for our experiments and useful discussions and advices, to Yu..V.Vinogradova for assistance in the realization of experiments and in the treatment of the results. 2003 Article Studies of light liner compression dynamics in plasma focus / M.A. Karakin, E.Yu. Khautiev, V.I. Krauz, A.N. Mokeev, V.V. Myalton, V.P. Smirnov // Вопросы атомной науки и техники. — 2003. — № 1. — С. 95-97. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 52.58.Lq https://nasplib.isofts.kiev.ua/handle/123456789/110547 en Вопросы атомной науки и техники application/pdf 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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DSpace DC |
| language |
English |
| topic |
Plasma dynamics and plasma-wall interaction Plasma dynamics and plasma-wall interaction |
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Plasma dynamics and plasma-wall interaction Plasma dynamics and plasma-wall interaction Karakin, M.A. Khautiev, E.Yu. Krauz, V.I. Mokeev, A.N. Myalton, V.V. Smirnov, V.P. Studies of light liner compression dynamics in plasma focus Вопросы атомной науки и техники |
| description |
The study is devoted to the investigation of plasma focus systems as a driver for magnetic compression of liners. The experiments on the comparative analyse of the foam and multiwired liners compression were done on the Filippov-type plasma focus facility PF-3. The compression of the light (linear mass 0.3-0.6 mg/cm) liners with velocity (2-3).10⁶ cm/s was obtained. It is shown that under conditions of considerable radiation fluxes at the usage of strongly-radiating working gases a preliminary heating of the target can be attained. This results in acceleration of the transition of initially – condensed substance into plasma state, that assists in overcoming “cool start” problem. |
| format |
Article |
| author |
Karakin, M.A. Khautiev, E.Yu. Krauz, V.I. Mokeev, A.N. Myalton, V.V. Smirnov, V.P. |
| author_facet |
Karakin, M.A. Khautiev, E.Yu. Krauz, V.I. Mokeev, A.N. Myalton, V.V. Smirnov, V.P. |
| author_sort |
Karakin, M.A. |
| title |
Studies of light liner compression dynamics in plasma focus |
| title_short |
Studies of light liner compression dynamics in plasma focus |
| title_full |
Studies of light liner compression dynamics in plasma focus |
| title_fullStr |
Studies of light liner compression dynamics in plasma focus |
| title_full_unstemmed |
Studies of light liner compression dynamics in plasma focus |
| title_sort |
studies of light liner compression dynamics in plasma focus |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2003 |
| topic_facet |
Plasma dynamics and plasma-wall interaction |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/110547 |
| citation_txt |
Studies of light liner compression dynamics in plasma focus / M.A. Karakin, E.Yu. Khautiev, V.I. Krauz, A.N. Mokeev, V.V. Myalton, V.P. Smirnov // Вопросы атомной науки и техники. — 2003. — № 1. — С. 95-97. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-11-27T15:34:56Z |
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STUDIES OF LIGHT LINER COMPRESSION DYNAMICS IN
PLASMA FOCUS
M.A. Karakin, E.Yu. Khautiev, V.I. Krauz, A.N. Mokeev, V.V. Myalton, V.P. Smirnov
RRC “Kurchatov Institute”, Institute of Nuclear Fusion, Moscow, 123182, Russia
The study is devoted to the investigation of plasma focus systems as a driver for magnetic compression of liners. The
experiments on the comparative analyse of the foam and multiwired liners compression were done on the Filippov-type
plasma focus facility PF-3. The compression of the light (linear mass 0.3-0.6 mg/cm) liners with velocity (2-3)⋅ 106 cm/s was
obtained. It is shown that under conditions of considerable radiation fluxes at the usage of strongly-radiating working gases a
preliminary heating of the target can be attained. This results in acceleration of the transition of initially – condensed
substance into plasma state, that assists in overcoming “cool start” problem.
PACS: 52.58.Lq
INTRODUCTION
The main goal of this study is the investigation of
plasma focus (PF) systems as driver for the magnetic liner
compression. The first studies shown the principal
opportunity of a similar approach were made in the joint
Russian-Polish experiment in Warsaw at the PF-1000-
facility [1]. The compression of the foam liner with the linear
mass of 200 µg/cm, at the discharge current amplitude of
1 MA, was observed in that experiment. Later on, the similar
experiments were made at the PF-3-facility, RRC
“Kurchatov Institute”, using the multiwired [2] and foam [3]
liners. This study is devoted to the comparative analyse of
the foam and multiwired liners compression on the Filippov-
type plasma focus facility PF-3.
EXPERIMENTAL SETUP
The experiments were done on the PF-3 facility
(Plasma Focus Filippov-type) at the energy level 450÷550
kJ and discharge current amplitude up to 3 MA. Scheme
of the experiments is shown in Fig.1. Discharges were
performed at the conditions of stationary filling by neon
at the pressure 1 Torr.
1 2
3
С0 S L
45
7
8 9
10
6
Fig.1 Scheme of the liner experiments
1 – anode; 2 – cathode; 3 – insulator; 4 – plasma
current sheath; 5 – anode insertion; 6 – suspension ware;
7 – liner; 8 – loading unit with a vacuum lock; 9, 10 –
diagnostics ports; C0 – capacitor bank; S – low pressure
spark gap switch; L – external inductance
A special device (Fig.2) with a vacuum lock has been
developed for liners delivering to the compression zone. This
allows one to execute the preliminary “training” of a discharge
chamber for improving the parameters of a plasma current
sheath and to perform the replacement of the liner without
violation of a vacuum in the chamber. The device is located
upon the upper cover (cathode) of the discharge chamber. All
the design elements are located outside the discharge volume
and they do not introduce heterogeneity violating the PCS-
dynamics. The liner (11) is suspended upon a thin (~ 60 µm)
polymeric (fishing-line) or metallic filament (10) and
descended to the necessary position at the system axis with the
mobile rod located in the cylindrical column sluice.
1
13
3
2
5
7
89
10
6
11
12
4
15
14
11
Fig.2. Design of a loading unit:
1 - anode; 2 - cathode; 3 - stationary protective
flange; 4 - rotary barrier; 5 - handle of a rotary barrier;
6 - vacuum lock; 7 - sluice column; 8 - vacuum - tight
input; 9 – metallic rod; 10 – suspension wire; 11 - liner;
12 - diagnostic ports; 13 - anode insertion; 14 - volume
for spent liners; 15 - PCS
The technology of wire array and foam liners production
has been developed at TRINITI (Troitsk). The wire array
design is a cylinder formed of 60 tungsten wires, 6 ÷ 8 µm in
diameter, 15 mm long. Wires are pulled between two metallic
discs along the diameter of 20 mm with a step of ~ 1 mm.
Two variants of foam liners made of agar-agar with
different diameters, 10 and 20 mm, were used in the
experiments. The specific foam density, ρ = 1 mg/cm-3. The
working liner surface height is 15 mm. A discernible feature
of liner design is the presence of a central supporting dielectric
rod, 3 mm in diameter, in some cases. The introduction of this
rod was a forced and unavoidable measure for light liners of
large diameter.
DIAGNOSTIC TECHNIQUES
In those experiments the main emphasis was done on
the compression dynamics study. The presence or absence
of the compression effect was considered as the main
factor in finding the prospects for the PF-3-facility
Problems of Atomic Science and Technology. 2003. № 1. Series: Plasma Physics (9). P. 95-97 95
implementation for these goals. Therefore the main
diagnostics at that stage were:
1. Measurement of a discharge current and that of
its derivative with the Rogowski coil and with
the magnetic probes;
2. Photographing of a pinch in the X-rays with the
two pin-hole cameras placed on the side
chamber surface at the angle 90° to the system
axis and on the upper flange at the angle of 60°;
3. Measuring of the X-ray radiation with Pin-
diodes. The time resolution is 1.5 ÷ 3 ns;
4. Study of the PCS-dynamics and of the pinch
formation in a visible light with a streak-camera
and with a 4-channel diagnostics based on
frame cameras at the frame exposure of 10 ns
and with time delay between frames of 150 ns
long;
EXPERIMENTAL RESULTS
Streak camera images of the discharges with the foam
liner of a small diameter 10 mm are given in Fig.3 b. A
streak camera image of a discharge without liner is given
for comparison in Fig.3a. The compression is observed
rather clearly. In a number of cases, the X-ray luminosity
takes place at the axis in zone the liner location (Fig.4)
that directly shows the pinching there.
Fig. 3. Streak camera images of the discharges
without liner (a) and with liner (b); liner diameter is
10 mm, m = 0.4 mg/cm, I = 2 MA
Fig. 4. Pin-hole pictures of the pinch without liner (a)
and with liner (b); direction of registration is 90° to the
system axis, diaphragm is 0.2 mm covered by Be 10 µm
filter
The very first experiment with the light liner (300 µ
g/cm) of a large diameter has reliably shown a
compression effect (Fig. 5a). A better space resolution has
allowed us estimate the compression rate: V ~ 2.5.
106 cm/s. In difference from the experiment in Warsaw
[1], we don’t observe a delay at the beginning of
compression, necessary for the transition of a foam
substance into a plasma state. Moreover, an initial radius
of the substance under compression somewhat exceeds
the initial liner radius. We consider it to be an
encouraging factor, confirming our assumption about the
possible preliminary liner heating by the sheath radiation.
This results in its expansion, on the one side, and
alleviates the discharge current “over-capture”, on the
other one.
Fig. 5. Streak-camera and frame camera pictures of
the discharges with 20 mm liner:
a) m=0.3 mg/cm, I = 2 MA, time shift between upper
and lower frame camera pictures, τ=150 ns;
b) m=1 mg/cm; I= 2 MA, τ=150 ns
The compression is stopped at the diameter of
6 – 7 mm, that can be explained by a stabilizing effect of
the central rod (liner armature, central rod included, is
well seen on the first frame camera picture). The very fact
that the plasma is located in the compressed state for a
long time (≥ 0.5 µs) is worth of attention. Subsequent fast
pinch destruction and the emergence of a luminosity in a
great zone we refer to the arrival of plasma fluxes and/or
of vapours of copper from a conical anode insertion.
We couldn’t detect the compression of a heavy liner
(1-4 mg/cm) at this value of a discharge current. The
plasma expansion occurs immediately after the sheath
shock at the liner (Fig. 5b).
Wire array liners possess of a number of peculiarities
in comparison with the foam ones:
- the presence of an initial conduction;
96
- the usage of the wires of different materials
allows one to change the radiation spectrum and
the intensity of a yield;
- the presence of the ordered structure, where the
wires are located with a step of ~ 1 mm in
difference from foam liner having the chaotic
structure with the characteristic non-homogeneity
size of about 30 µm.
One of the premises for performing the experiments
with the wire arrays was their successful implementation
in the recent experiments with fast systems [4].
It has been shown that, after current sheath contact
with the liner, an essential portion of a current continues
to flow in the vicinity to the wires during the period
necessary for transferring the current to the liner. But
some portion of a current is “dropped” down to the axis,
producing a pinch. The very wires remain to be immobile
during ~ 150 ns for the light liner and during ~ 300 ns for
the heavy one, then a rather fast compression of the liner
to the axis occurs. The rate of this compression, estimated
from the streak camera pictures, is about 3.106 cm/s for
the light liner, and ~ 2.106 cm/s for the heavy one (Fig.6).
Thus the time of the current switching on the wire array
and velocity of its consequent compression to axis depend
from linear mass of the liner. Later on, a comparatively-
slow pinch expansion takes place at the rates
approximately-lower than the compression ones by the
order of magnitude.
Fig. 6. Streak camera pictures:
a) discharge in neon without liner;
b) wire array, 330 µg/cm; c) wire array, 600 µg/cm
CONCLUSIONS
The main result of these experiments is, first of all, the
conclusion about an opportunity to realize the liner
compression at the PF-3 facility. The compression of the light
liners, both foam and multiwire ones, with velocity (2-3) 106
cm/s was obtained. The final result can be affected by the
shape and symmetry of the sheath, as well as by the quality of
a given liner manufacture. Along with the identity of many
physical processes in a plasma focus, Mather’s type and
Filippov’s type, there is a number of the differences in a
plasma current sheath dynamics which can essentially affect
the process of interaction between the current sheath and the
liner. One of them is the presence of a long duration radial
compression stage (~ 10 µs) in the flat electrode geometry.
Under conditions of considerable radiation fluxes at the usage
of strongly-radiating working gases (neon, for example) a
preliminary heating of the target located at the axis and
acceleration of the initially – condensed substance transition
into plasma state can be attained. Therefore, in such discharge
one can effectively control over the process of the liner
evaporation and ionization by changing the liner parameters
that assists in overcoming “cool start” problem.
ACKNOWLEDGEMENTS
We are grateful to S.L.Nedoseev and
S.F.Medovschikov (TRINITI) for liners manufacturing
for our experiments and useful discussions and advices, to
Yu..V.Vinogradova for assistance in the realization of
experiments and in the treatment of the results.
REFERENCES
1. M.Scholz, L.Karpinski, W.Stepnievski et al.,
Phys.Lett., 1999, A 262, p. 453.
2. V.V.Myalton, V.I.Krauz, E.Yu.Khautiev et al., Int.
Symp. PLASMA-2001, Warsaw, Poland, 2001, O8-2,
http://www.ifpilm.waw.pl/Plasma2001/#topic8.
3. M.A. Karakin, E.Yu. Khautiev, V.I. Krauz et al.,
Czhechoslovak Journal of Physics, Vol.52, Suppl.D
(2002), 255-263.
4. T.W.L.Sanford, R.E.Olson, R.C.Mock et.al.
Physics of plasmas, v.7, N.11, November 2000, p.4669.
ДОСЛІДЖЕННЯ ДИНАМІКИ СТИСНЕННЯ ЛЕГКИХ ЛЕЙНЕРІВ В ПЛАЗМОВОМУ ФОКУСІ
М.А. Каракін, Е.Ю. Хаутієв, В.І. Крауз, А.М. Мокеєв, В.В. Мялтон, В.П. Смірнов
Робота присвячена дослідженню плазмового фокусу (ПФ) в ролі драйверa для магнітного обтиснення лайнерів.
Проведено експерименти з порівняльного аналізу стиснення пінних й багатодротових лайнерів на установці типу
Філіппова ПФ-3. Отримано стиснення лайнерів з погонною масою 0.3-0.6 мг/см зі швидкостями (2-3).106 см/с при
амплітуді розрядного струму 2 МА. Показано, що в умовах значних радіаційних потоків при використанні
сильновипромінюючих робочих газів може бути здійснений попередній нагрів мішені. Це призводить до прискорення
переходу первісно конденсованої речовини у плазмовий стан, що дає змогу подолати проблему «холодного старту».
ИССЛЕДОВАНИЕ ДИНАМИКИ СЖАТИЯ ЛЕГКИХ ЛАЙНЕРОВ В ПЛАЗМЕННОМ ФОКУСЕ
M.A. Каракин, Э.Ю. Хаутиев, В.И. Крауз, А.Н. Мокеев, В.В. Мялтон, В.П. Смирнов
Работа посвящена исследованию плазменного фокуса (ПФ) в качестве драйвера для магнитного обжатия лайнеров.
Проведены эксперименты по сравнительному анализу сжатия пенных и многопроволочных лайнеров на установке типа
Филиппова ПФ-3. Получено сжатие лайнеров с погонной массой 0.3-0.6 мг/см со скоростями (2-3).106 см/с при амплитуде
разрядного тока 2 МА. Показано, что в условиях значительных радиационных потоков при использовании
сильноизлучающих рабочих газов может быть осуществлен предварительный нагрев мишени. Это приводит к ускорению
97
перехода первоначально конденсированного вещества в плазменное состояние, что способствует преодолению проблемы
“холодного старта ”.
98
M.A. Karakin, E.Yu. Khautiev, V.I. Krauz, A.N. Mokeev, V.V. Myalton, V.P. Smirnov
INTRODUCTION
experimental setup
CONCLUSIONS
Acknowledgements
REFERENCES
ИССЛЕДОВАНИЕ ДИНАМИКИ СЖАТИЯ ЛЕГКИХ ЛАЙНЕРОВ В ПЛАЗМЕННОМ ФОКУСЕ
M.A. Каракин, Э.Ю. Хаутиев, В.И. Крауз, А.Н. Мокеев, В.В. Мялтон, В.П. Смирнов
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