Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M”
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
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| Cite this: | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” / O.A. Lavrent’ev, V.A. Maslov, S.V. Germanova, M.G. Nozdrachev, V.P. Oboznyi // Вопросы атомной науки и техники. — 2000. — № 3. — С. 48-50. — Бібліогр.: 3 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860130830093910016 |
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| author | Lavrent’ev, O.A. Maslov, V.A. Germanova, S.V. Nozdrachev, M.G. Oboznyi, V.P. |
| author_facet | Lavrent’ev, O.A. Maslov, V.A. Germanova, S.V. Nozdrachev, M.G. Oboznyi, V.P. |
| citation_txt | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” / O.A. Lavrent’ev, V.A. Maslov, S.V. Germanova, M.G. Nozdrachev, V.P. Oboznyi // Вопросы атомной науки и техники. — 2000. — № 3. — С. 48-50. — Бібліогр.: 3 назв. — англ. |
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| first_indexed | 2025-12-07T17:44:44Z |
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Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 48-50
48
UDC 533.9
NEUTRAL GAS INFLUENCE ON PLASMA HEATING AND
CONFINEMENT IN THE MULTISLIT ELECTROMAGNETIC TRAP
“JUPITER 2M”*
O.A.Lavrent’ev, V.A.Maslov, S.V.Germanova, M.G.Nozdrachev, V.P.Oboznyi,
Institute of Plasma Physics National Science Center Kharkiv Institute of Physics and
Technology, Kharkiv, Ukraine, <lavr@ipp.kharkov.ua>, tel 0572 35 64 38
INTRODUCTION
The basic idea of electromagnetic traps is cashing
character of plasma confinement. The plasma in these
traps is kept in the cashing formed by combined
electrical and sharp-angle magnetic fields (in the central
part of a trap the fields are absent). The plasma
cooperates with these fields in a thin superficial layer,
and its central part is in powerless, thermally
equilibrium condition. Such system of the combined
plasma confinement by electrical and magnetic fields
has unique properties allowing to struggle successfully
with plasma instability of a various type. As against
other systems with magnetic plasma confinement width
of diffusion layer in an electromagnetic trap is limited
by a flow through magnetic slit, which can not be wide
because of a condition of ions confinement in a
potential well. Really in electromagnetic traps width of
diffusion layer makes 20-60 Larmor’s radius of
electrons, and the question about character of electrons
transfer has basic importance for an estimation of
prospects of creation thermonuclear reactor based an on
electromagnetic trap. Therefore data of density change
in volume of plasma confinement during a pulse of
injection are necessary for finding - out the character of
electrons diffusion.
The influence of neutral gas on plasma heating and
confinement in multislit electromagnetic trap is
considered in the report.
MULTISLIT ELECTROMAGNETIC
TRAP“JUPITER 2M “
The experiments were carried out on installation
"Jupiter 2M"1. A magnetic field of installation, the fig.
1, has axial symmetric multipole structure with seven
ring magnetic slits in the central part and axial holes on
the ends. Length of magnetic system between axial
fuses makes 1.3 ì, diameter of a ring slit - 0.43 ì,
diameter of axial holes - 0.025 m. The maximal strength
of a magnetic field in a ring slit BA=9 kG. Strength of a
magnetic field in axial Holes BA0=2BA.
The spatial distribution of a magnetic field in the region
of plasma confinement is characterized by a deep
magnetic well, so at r 0.1m,
z ≤
0.25 m takes
place Â/ÂÀ < 5%. All magnetic slits are closed by
system of electrodes with high negative potential. The
plasma in a trap is created with the help of electrons
injection through axial holes.
The experiments have confirmed high efficiency of
plasma creation in a multislit electromagnetic trap with
the help of electrons injection. At moderate power
contribution 10-4J/ñm3 and weak magnetic field 500 gs
on a limiting magnetic surface in "Jupiter 2M" the
plasma of density 1012 cm-3 in volume 50 l is received.
The absence of high-frequency plasma activity and
monotonous (without failures) growth of its parameters
during all time of accumulation are marked.
Fig. 1. A configuration of magnetic force lines of a
multislit electromagnetic trap«Jupiter2M »
A - magnetic ring slit,
B- arrangement of a probe for measurement of neutral
gas density.
EXPERIMENTAL RESULTS
It was experimentally observed, that the pulse of
plasma accumulation in a trap is accompanied by
increase of neutral gas pressure in the vacuum chamber
of installation. In the beginning it was assumed, that the
gas is allocated during disintegration of plasma owing to
its interaction with walls of the chamber. Later was
noticed, that the pressure of gas changes already at an
initial stage of plasma accumulation.2,3 As the neutral
gas significantly influences on heating and diffusion of
electrons, it is interest to estimate change of its density
in volume of plasma confinement during a pulse of
injection.
Density of neutral gas in a trap was measured with
the help of the specially made probe, which was placed
near to an extreme magnetic surface limiting area of
plasma accumulation, in a face part of a trap, fig 1, B. In
a fig. 2 the circuit of a probe is shown which works by a
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 48-50
49
principle of a ionization lamp in a range of pressure 10-3
– 10-6 Tor with enough high time thin-bed vertical
resolution . The probe is placed
The cathode (+30 V) Grid (anode+250 V) Collector (0)
Fig. 2. The circuit of a probe for measurement of
temporary dependences of neutral gas pressure.
in the special screen, which prevents hit of the charged
particles on its electrodes. The calibration of a probe in
a magnetic field of a trap was carried out. The
calibration curve is given in a fig. 3.
Fig. 3. Calibration curve of a probe.
A change of neutral gas density (bottom curves),
strength of magnetic field, current cross electrons
transfer are given in a fig. 4, 5. On oscillograms of a
magnetic field strength the pulse of electrons injection
is imposed on, during which there is a plasma
accumulation in a trap.
From oscillograms it is visible, that the increase of
neutral gas density occurs at once of a beginning of a
pulse of electrons injection and density is increased at 8 -
20 of time by the end of a pulse of injection depending
on mode of operations of installation. The increase of
neutral gas density during a pulse of injection is
connected with its knockout from surfaces of magnetic
0 5 10 15 20 25 30 35 40 ms
Fig. 4. Oscillograms of a magnetic field strength (top)
and density of neutral gas (bottom).
0 1 2 3 4 5 6 7 ms
Fig. 5. Oscillograms of cross electrons transfer (top)
and neutral gas density (bottom).
and electrostatic systems located near to area of plasma
accumulation, charged particles and radiation from
plasma. A condition of electrostatic and magnetic
systems surfaces significantly influence on neutral gas
density increase during pulse of injection, therefore
experiments were carried out after their processing by
preliminary shots.
Density of neutral gas during a pulse of injection
grows with increase of a current and energy of injection,
but decreases with growth of a magnetic field strength.
The dependences of neutral gas density at the end of a
pulse of injection from strength of a magnetic field for
currents of injection 150 and 220 mA are given on fig 6.
Thus initial neutral gas density makes 1.4 1011cm-3.
In the same figure the dependences of plasma density in
a trap is given under the same conditions. Density of
plasma was measured by 8 mm interferometer.
The increasing of neutral gas density with increasing
of magnetic field strength at small magnetic field value
is connected with boundary magnetic field, at which
Larmor radius of injected electrons is smaller than
Problems of Atomic Science and Technology. 2000. N 3. Series: Plasma Physics (5). p. 48-50
50
magnetic slit width and effective accumulation of
plasma is started.
Decrease of neutral gas density with the further
increasing of magnetic field strength is connected with
decrease of Larmor radius and with decrease of the
surface from which neutral gas is knocking out.
The dependence of neutral gas and plasma density from
magnetic field strength explains early received
Fig. 6. The neutral gas n(a) and plasma n(e) density at
finish pulse of injection dependencies from magnetic
field strength in magnetic slit.
dependences of relation of experimental measured and
theoretically estimated currents of electrons under
assumption of classical diffusion cross magnetic field
from plasma density, fig. 72.
Fig 7. Dependence of experimental and theoretical ratio
of electrons cross field transfer from plasma density.
BA = 3.75 kG(·); 5.0 kG(+); 6.25 kG (*)
On figure 7 the relation of experimental currents of
cross electrons diffusion to theoretical for various
currents and energy of injection are given at intensity of
a magnetic field in a magnetic slit ÂA = 3.75 (· ), 5.0 (+),
6.25 (*) êGs. It is visible from figure, that with growth
of plasma density the relation of experimental currents
to theoretical one decreases and for density of plasma ne
=1012 ñì-3 does not exceed 2-3. From comparison of
results of neutral gas and plasma density measured
dependences from magnetic field strength (the fig. 6)
and from relation of experimental and theoretical
currents of cross electrons diffusion it is possible to
note, that change of neutral gas pressure during impulse
of injection is determinative in increasing of cross
electron transfer as the result of their diffusion on
neutral particles.
The results of these researches allow to make a
conclusion about classical character of cross electrons
transfer in a multislit electromagnetic trap "Jupiter 2Ì".
These results will be used for updating mathematical
model of plasma accumulation, heating and
confinement in a multislit electromagnetic trap.
REFERENCES
1. Vdovin S. A.,Lavrent’ev O. A., Maslov V. A.,
Nozdrachov M. G., Oboznyj V. P., Sappa N. N.
Plasma storage in the multislit electromagnetic trap
“Jupiter 2M”. Voprosy Atomnoj Nauki i tekhniki,
seriya Termoyadernyj Sintez 3, Moskow, 1989, pp
40-45.
2. Lavrent’ev O. A., Maslov V. A., Germanova S. V.,
Nozdrachov M. G., Oboznyj V. P., Shevchuk B. A.
Investigation of the fundamental processes of
plasma accumulation, heating and confinement in
the multislit electromagnetic trap. 23rd European
Physical Society Conference on Controlled Fusion
and Plasma Physics, Kiev, 24-26 June, 1996, part
II, p. 679-680.
3. Lavrent’ev O. A., Maslov V. A., Germanova S. V.,
Nozdrachov M. G., Oboznyj V. P., Shevchuk B. A.
Investigation of plasma confinement in the multislit
electromagnetic trap. Problems of Atomic Science
and Technology, series Plasma Physics, Kharkov
1999, V.1, p. 108-110.
.
* The research described in this publication was made
possible in part by Grant #1341 from STCU
|
| id | nasplib_isofts_kiev_ua-123456789-82367 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T17:44:44Z |
| publishDate | 2000 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Lavrent’ev, O.A. Maslov, V.A. Germanova, S.V. Nozdrachev, M.G. Oboznyi, V.P. 2015-05-29T06:09:57Z 2015-05-29T06:09:57Z 2000 Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” / O.A. Lavrent’ev, V.A. Maslov, S.V. Germanova, M.G. Nozdrachev, V.P. Oboznyi // Вопросы атомной науки и техники. — 2000. — № 3. — С. 48-50. — Бібліогр.: 3 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/82367 533.9 The research described in this publication was made 
 possible in part by Grant #1341 from STCU en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Мagnetic Confinement Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” Article published earlier |
| spellingShingle | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” Lavrent’ev, O.A. Maslov, V.A. Germanova, S.V. Nozdrachev, M.G. Oboznyi, V.P. Мagnetic Confinement |
| title | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” |
| title_full | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” |
| title_fullStr | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” |
| title_full_unstemmed | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” |
| title_short | Neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “Jupiter 2M” |
| title_sort | neutral gas influence on plasma heating and confinement in the multislit electromagnetic trap “jupiter 2m” |
| topic | Мagnetic Confinement |
| topic_facet | Мagnetic Confinement |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/82367 |
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