Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods
Results of shadowgraphic and interferometric studies of physical processes in both a magnetoplasma compressor (MPC) and a two-stage quasistationary high-current plasma accelerator (QHPA) of P-50M type are presented. Use of these methods has enabled definition of basic gas- and thermodynamic paramete...
Saved in:
| Published in: | Вопросы атомной науки и техники |
|---|---|
| Date: | 2000 |
| Main Authors: | , , , |
| Format: | Article |
| Language: | English |
| Published: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
|
| Subjects: | |
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/82371 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods / S.I. Ananin, V.M. Astashynski, E.A. Kostyukevich, L.Ya. Min'ko // Вопросы атомной науки и техники. — 2000. — № 3. — С. 87-89. — Бібліогр.: 3 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859716917094252544 |
|---|---|
| author | Ananin, S.I. Astashynski, V.M. Kostyukevich, E.A. Min'ko, L.Ya. |
| author_facet | Ananin, S.I. Astashynski, V.M. Kostyukevich, E.A. Min'ko, L.Ya. |
| citation_txt | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods / S.I. Ananin, V.M. Astashynski, E.A. Kostyukevich, L.Ya. Min'ko // Вопросы атомной науки и техники. — 2000. — № 3. — С. 87-89. — Бібліогр.: 3 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | Results of shadowgraphic and interferometric studies of physical processes in both a magnetoplasma compressor (MPC) and a two-stage quasistationary high-current plasma accelerator (QHPA) of P-50M type are presented. Use of these methods has enabled definition of basic gas- and thermodynamic parameters of plasma flows in such accelerators.
|
| first_indexed | 2025-12-01T08:12:49Z |
| format | Article |
| fulltext |
UDC 533.9
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 87-89 87
INVESTIGATIONS OF COMPRESSION PLASMA FLOWS
IN QUASISTATIONARY PLASMA ACCELERATORS
BY INTERFERENCE-SHADOWGRAFY METHODS
S.I.Ananin, V.M.Astashynski, E.A.Kostyukevich, L.Ya.Min'ko
Institute of Molecular and Atomic Physics
National Academy of Sciences of Belarus, Minsk, Belarus
E-mail: ast@imaph.bas-net.by
Results of shadowgraphic and interferometric studies of physical processes in both a magnetoplasma compressor
(MPC) and a two-stage quasistationary high-current plasma accelerator (QHPA) of P-50M type are presented. Use
of these methods has enabled definition of basic gas- and thermodynamic parameters of plasma flows in such accel-
erators.
INTRODUCTION
Among the most informative and yet extremely
complicated techniques for diagnostics of plasma accel-
erators are interferometric and shadowgraphic methods
based on visualization of optical inhomogeneities in
objects under study. Due to unique features inherent in
such methods, these latter provide a possibility to obtain
an extensive and reliable information without adverse
effects to parameters of plasma being investigated.
However, practical implementation of shadow and
interference methods is involved with certain difficulties
resulting primarily from complexity of conventional
devices. The additional problems arise when it comes to
studying objects in vacuum chambers. These drawbacks
may be minimized by the use of a two-mirror autocol-
limation interferometer with visualization of field of
view [1], developed specially for diagnostics of physical
processes in plasma accelerators. Due to the implemen-
tation of autocollimation concept coupled with
monoaxial arrangement of optical elements the device
with the 200-mm field of view has desk-top dimensions
and can easily be installed practically at any experimen-
tal setup.
This paper presents results of shadowgraphic and in-
terferometric studies of plasma flows generated by both
a magnetoplasma compressor (MPC) [2] and a two-
stage quasistationary high-current plasma accelerator
(QHPA) of P-50M type [3].
EXPERIMENTAL
The operation of electrodynamic valves delivering a
working gas into MPC and QHPA, was monitored using
the developed shadow-interferometric device (Fig. 1).
The radiation of the He-Ne laser 4 r eflected by a wedge-
shaped quartz plate 3 with 50 % and 99 % reflecting
coatings on front and rear surfaces accordingly, is split
into two coherent beams. Spatial frequency of interfer-
ence fringes formed on a diaphragm 5 with narrow slot
mounted in front of a photo multiplier 6 (PM), depends
on a wedge angle and a distance between the wedged
plate and the diaphragm. Development of optical non-
uniformity in the path of beams causes the fringe pattern
to shift relative to the slot, resulting in the PM signal
modulation recorded by a storage oscillograph. The
typical oscillogram of the gas pulse shape obtained by
the above method, is shown in Fig. 2.
The device sensitivity at the specified fringe width is
determined by both a distance from the nonuniformity
to the diaphragm and the slot width. Among advantages
of the technique as compared to available shadow meth-
ods are low sensitivity to vibrations and ability to con-
duct measurements without resorting to complicated
procedure of preliminary calibration.
The electron concentration of plasma formations in
channels of both MPC and QHPA was determined using
the laser interferometer. To that end the diagram in
Fig. 1 was changed as follows: PM was placed behind a
rear mirror of the laser, a retroreflecting mirror was
mounted in place of PM, and a wedge-shaped plate was
faced by highly reflecting surface towards a laser beam.
A typical interferogram obtained in such a way upon
probing the P-50M type QHPA accelerating channel,
and corresponding changes in the electron concentration
are shown in Fig. 3.
The measurements of electron concentrations in both
MPC and QHPA compression plasma flows were con-
ducted with the spatio-temporal resolution using various
1000 µs
Fig 2.
Fig. 1. Diagram of shadow-interferometric device
1— vacuum chamber, 2 — accelerator, 3 — wedge-
shaped plate, 4 — laser, 5— diaphragm, 6 — PM
88
versions of the two-mirror autocollimation interferome-
ter with fields of view in range from 50 up to 200 mm,
depending on experimental conditions. Interference pat-
terns were recorded with a high-speed photorecorder
VFU in frame mode enabling in a single experiment a
series of interferograms, and thus temporal variations in
a phase refractive index of a plasma formation through-
out the field of view, to be obtained. The use of a ruby
laser operating in a free-running mode with mode selec-
tion as a probing light source, ensures the temporal reso-
lution not worse than100 ns at a photorecorder frame
rate about 250000 fps.
Shown in Fig. 4 is a diagram of the 200 mm inter-
ferometer mounted on the P50-M QHPA experimental
setup. The collimating optics transforms a laser radia-
tion into a parallel beam 200 mm in diameter. The front
and rear interferometric semitransparent mirrors retrore-
flect reference and object beams respectively. Upon
passing through the collimating optics, both beams are
directed by a deflecting mirror at the photorecorder
VFU. To process the obtained interferograms, an auto-
mated system with software support providing a way of
obtaining the electron density radial distributions via
Tikhonov's regularization, was developed.
Interferometric studies of both MPC and P50-M
QHPA were carried out at a single wavelength of a
probing ruby laser, since the plasma refraction in a
range of parameters (Òe ~ 1÷15 eV, Ne ~ 1015÷1017 ñì-3)
characteristic of MPC and QHPA, according to the pre-
liminary analysis is determined mainly by free elec-
trons. Thus, concentration of electrons in plasma is de-
termined by the expression:
l
k
N e
1
2
1021,3 17 ⋅⋅−= ,
where Ne — concentration of electrons in plasma, k —
shift of interference fringes relative to their initial posi-
tions in absence of plasma, l — thickness of plasma
formation in direction of probing. The relative error in
measurements of electron density determined by an un-
certainty in definition of both fringe shift and linear size
of plasma, does not exceed 10 %. Typical interferogram
of a QHPA compression flow and corresponding spatial
and temporal distributions of electron concentration in
plasma are shown in Fig. 5 and Fig. 6, respectively.
Plasma temperature was determined from results of
experiments on a supersonic compression flow inci-
dence on a thin wedge with an acute leading edge. Lines
of perturbations emerging on the leading edge were
visualized by a shadow instrument with double passage
of a probing laser beam through an area under study. In
Fig. 3. a — interferogram;
b — electron concentration in QHPA accelerating channel
100 µs
a
Fig. 4. Diagram of the interferometer mounted on the
QHPA: 1 — input ionization chamber, 2 — cathode
transformer, 3 — anode transformer, 4 — telescope, 5
— beam splitter, 6 and 7 — interferometer mirrors,
and 8 — high speed photographic camera.
b
Fig. 5
89
this case interferometer diagram shown on the Fig. 4
was changed as follows. The front mirror 6 of interfer-
ometer was removed and the rear mirror 7 was replaced
by a plate with 99 % reflecting coating. Fig. 7 presents a
typical shadow picture of a flowfield originating in the
course of the QHPA plasma flow incidence on the
wedge. Knowing a velocity of a compression plasma
flow and inclination of a perturbation line with respect
to a wedge (Mach angle), it is possible to find the
plasma temperature:
)1(
)sin(
2
zk
iMplV
T pl
+
⋅⋅
≈
γ
α
,
where Vpl —velocity of a compression plasma flow, α
— Mach angle, Mi — a mass of an ion, z — a charge of
an ion, k — a Boltzmann constant, γ — Poisson isen-
tropic exponent. Under experimental conditions typical
in P-50M QHPA, the plasma temperature determined by
the above method, makes 10-15 eV.
The measured values of temperature and concentra-
tion of electrons in the P-50M QHPA plasma have en-
abled the gas-kinetic pressure of compression plasma
flow to be defined: under conditions of experiments it
attained ~ (2÷3)⋅105 Pa.
Thus, due to the use of shadow-interferometric
methods in studies of physical processes in quasista-
tionary plasma accelerators the spatio-temporal distribu-
tions of main thermodynamic parameters of plasma in
such systems were obtained.
REFERENCES
1. E.A.Kostyukevich, L.Ya.Min'ko. Two-mirror autocollimation interferometer with the field visualization // Jour-
nal of Applied Spectroscopy. 1981, v. 34, ¹ 3, p. 551-555.
2. V.M. Astashynski, V.V.Efremov, E.A.Kostyukevich et al. Interference-shadow studies of the processes in a mag-
netoplasma compressor // Sov. J. Plasma Phys. 1991, v. 17, ¹ 9, p. 545-548.
3. S. I. Ananin, V. M. Astashinskii, E. A. Kostyukevich et al. Interferometric studies of the processes occurring in a
quasi-steady high-current plasma accelerator // Plasma Physics Report (translated from Fizika Plasmy). 1998, v. 24,
¹ 11, p.936-942.
Fig. 6. a — temporal evolution of the electron density in the plasma flow of the QHPA;
b — spatial electron density distribution in the plasma flow in the QHPA
a b
Fig. 7
|
| id | nasplib_isofts_kiev_ua-123456789-82371 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-01T08:12:49Z |
| publishDate | 2000 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Ananin, S.I. Astashynski, V.M. Kostyukevich, E.A. Min'ko, L.Ya. 2015-05-29T06:19:30Z 2015-05-29T06:19:30Z 2000 Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods / S.I. Ananin, V.M. Astashynski, E.A. Kostyukevich, L.Ya. Min'ko // Вопросы атомной науки и техники. — 2000. — № 3. — С. 87-89. — Бібліогр.: 3 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/82371 533.9 Results of shadowgraphic and interferometric studies of physical processes in both a magnetoplasma compressor (MPC) and a two-stage quasistationary high-current plasma accelerator (QHPA) of P-50M type are presented. Use of these methods has enabled definition of basic gas- and thermodynamic parameters of plasma flows in such accelerators. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Рlasma Dynamics and Plasma-Wall Interaction Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods Article published earlier |
| spellingShingle | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods Ananin, S.I. Astashynski, V.M. Kostyukevich, E.A. Min'ko, L.Ya. Рlasma Dynamics and Plasma-Wall Interaction |
| title | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods |
| title_full | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods |
| title_fullStr | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods |
| title_full_unstemmed | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods |
| title_short | Investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods |
| title_sort | investigations of compression plasma flows in quasistationary plasma accelerators by interference-shadowgrafy methods |
| topic | Рlasma Dynamics and Plasma-Wall Interaction |
| topic_facet | Рlasma Dynamics and Plasma-Wall Interaction |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/82371 |
| work_keys_str_mv | AT ananinsi investigationsofcompressionplasmaflowsinquasistationaryplasmaacceleratorsbyinterferenceshadowgrafymethods AT astashynskivm investigationsofcompressionplasmaflowsinquasistationaryplasmaacceleratorsbyinterferenceshadowgrafymethods AT kostyukevichea investigationsofcompressionplasmaflowsinquasistationaryplasmaacceleratorsbyinterferenceshadowgrafymethods AT minkolya investigationsofcompressionplasmaflowsinquasistationaryplasmaacceleratorsbyinterferenceshadowgrafymethods |