The formation of near anode double layer in highcurrent plasma diode of low pressure
A plasma electron source on the basis of a pulse plasma diode of low pressure with an extended interelectrode gap has been experimentally investigated. The basis of a plasma electron source serves a gas discharge of a new type - selfmaintained beam-plasma discharge, which distinctive feature is the...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2002 |
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| Формат: | Стаття |
| Мова: | Англійська |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2002
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | The formation of near anode double layer in highcurrent plasma diode of low pressure / A.F. Tseluyko, D.V. Zinov’ev, V.N. Borisko, V.A. Tseluyko, A.A. Drobishevskaya // Вопросы атомной науки и техники. — 2002. — № 5. — С. 127-129. — Бібліогр.: 6 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859662559976620032 |
|---|---|
| author | Tseluyko, A.F. Zinov’ev, D.V. Borisko, V.N. Tseluyko, V.A. Drobishevskaya, A.A. |
| author_facet | Tseluyko, A.F. Zinov’ev, D.V. Borisko, V.N. Tseluyko, V.A. Drobishevskaya, A.A. |
| citation_txt | The formation of near anode double layer in highcurrent plasma diode of low pressure / A.F. Tseluyko, D.V. Zinov’ev, V.N. Borisko, V.A. Tseluyko, A.A. Drobishevskaya // Вопросы атомной науки и техники. — 2002. — № 5. — С. 127-129. — Бібліогр.: 6 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | A plasma electron source on the basis of a pulse plasma diode of low pressure with an extended interelectrode gap has been experimentally investigated. The basis of a plasma electron source serves a gas discharge of a new type - selfmaintained beam-plasma discharge, which distinctive feature is the forming of a double electrical layer of a space charge in a discharge gap and generation of an intensive electron beam. The exterior parameters were determined, at which formation of a double layer and the acceleration of an electron beam in such discharge occurs immediately at working area of the anode. The plasma electron source is calculated on generation of an electron beam with the energy 〖10〗^4…〖10〗^5 eV at the current 2…3 kA, current density 200…300 A/cm 2 , pulse length 1…10 μs and efficiency of conversion of an exterior electric field energy into an electron beam energy up to 80%.
|
| first_indexed | 2025-11-30T10:31:54Z |
| format | Article |
| fulltext |
THE FORMATION OF NEAR ANODE DOUBLE LAYER IN HIGH-
CURRENT PLASMA DIODE OF LOW PRESSURE
A.F. Tseluyko, D.V. Zinov’ev, V.N. Borisko, V.A. Tseluyko, А.А. Drobishevskaya
Kharkov National University, 61108, 31 Kurchatov Av., Kharkov, Ukraine,
E-mail: Borisko@pht.univer.kharkov.ua
A plasma electron source on the basis of a pulse plasma diode of low pressure with an extended interelectrode gap
has been experimentally investigated. The basis of a plasma electron source serves a gas discharge of a new type - self-
maintained beam-plasma discharge, which distinctive feature is the forming of a double electrical layer of a space
charge in a discharge gap and generation of an intensive electron beam. The exterior parameters were determined, at
which formation of a double layer and the acceleration of an electron beam in such discharge occurs immediately at
working area of the anode.
The plasma electron source is calculated on generation of an electron beam with the energy 104…105 eV at the
current 2…3 kA, current density 200…300 A/cm2, pulse length 1…10 μs and efficiency of conversion of an exterior
electric field energy into an electron beam energy up to 80%.
PACS: 52.40.Hf
INTRODUCTION
Formation of the double layer in a high-current arc
discharge of low pressure, which is accompanied by sharp
increase of discharge voltage, is not simple change of
discharge parameters but transition to new kind of a self-
maintained discharge in gas - independent beam-plasma
discharge (IBPD) [1]. Such discharge is following after
arc (according to Fransis scale [2]) new kind of an
independent gas discharge. In IBPD electrons are emitted
from the cathode similar to arc discharge by the cathode
spots, and the carry of a current is performed by an
electron beam similar to beam-plasma discharge with
external injection of an electron beam.
Two types of independent beam-plasma discharge
exist: K - discharge and M - discharge, which differ by a
place of double layer localization and dynamics of
processes [3]. In case of K - discharge the double layer is
at the front of the dense plasma of cathode spots [4],
which "wrings out" rather rare plasma of an interelectrode
interspace from the cathode. The localization of the
double layer in an interelectrode interspace in the region
of the least current conductivity of a plasma column is the
property of M - discharge [5].
At creation of a plasma electron source on the basis of
an extended plasma diode of low pressure for lowering
power losses of an electron beam in plasma it is necessary
to form the double layer directly near the surface of the
anode. In this case the electrons, accelerated in the double
layer, at once fall on the anode. Thus, the greatest
conversion coefficient of electrical field energy in an
electron beam energy is reached, as the energy losses on
interaction of the beam with plasma of the discharge gap
are completely eliminated. In other words, in the plasma
electron source the M - discharge should be excited with
near anode voltage drop.
For excitation of such discharge in a plasma diode it is
necessary to execute a number of conditions. At first, the
general condition of IBPD excitation should be executed,
which coincides with the condition of double layer
formation. It is realized when the discharge current
reaches the greatest possible value of the critical current
Iс. It is determined by the peak current, which can be
transferred by plasma due to thermal motion in conditions
of low pressure:
( ) sdmkTrenI
S
eepc 8
4
1 π∫= , (1)
here е, me and Те are the charge, mass and temperature of
the plasma electrons accordingly, ( )rn
p is the plasma
density in the selected point, S is the current-carrying
cross-section of the plasma column. At identical current-
carrying cross-section of the plasma column the minimum
critical value of the current Iс exists in the region of a
minimum plasma density, where the double layer is
formed.
From here second condition follows. For the double
layer formation near the anode the plasma density should
be minimum here. The gradient of the plasma density can
be created by a pressure gradient of neutral gas, as, in
conditions of intensive pulse discharges the neutral gas is
ionized during time much shorter than time of plasma
diffusion [6].
Also additional condition, improving system
effectiveness, exists. For direct formation of M -
discharge with exception of intermediate stage of K -
discharge the primary plasma column should take all
cross-section of the discharge tube [3].
For creation of the electron source on the basis of an
extended plasma diode the experiments on formation of
M - discharge in conditions of a pressure gradient with
heightened density in near cathode region were
performed.
EXPERIMENTAL SAMPLE OF THE PLASMA
SOURCE OF THE ELECTRONS
Outgoing from offered idea, the design of the
experimental sample of the pulse plasma source of the
electron beam was developed. The design of the source is
shown in Fig. 1.
Problems of Atomic Science and Technology. 2002. № 5. Series: Plasma Physics (8). P. 127-129 127
The plasma source of the electrons consists from the
discharge tube 1, the cathode unit 2 with the source of the
preliminary plasma, the anode unit 3 and the divider of
the voltage 4. Discharge tube from a glass has a minor
diameter of 56 mm and length of 450 mm at wall
thickness of 6 mm. The experimental sample is calculated
for currents up to 30 kA and voltage up to 100 kV. In the
working order this device joins the vacuum installation
with limit pressure not worse than 10–5 Torr and rate of
pumping out of hydrogen not below 500 l/s at pressure
10–4 Torr.
The companion flange 5 in the assembly, anode 6 and
Rogovsky belt 7 for measurement of the discharge current
enters in an anode unit. For a passage of gas in a
companion flange there are 12 pumping out holes of
diameter 10 mm, and also central threated hole for
attachment of the anode. The anode represents changeable
hollow copper glassful with external diameter of 27 mm,
which by means of a thread connection fastens to a
companion flange.
For determination of the functionability of the
experimental sample of the plasma source of the electrons
the preliminary tests were performed. The experiments
were performed at lowered voltage of the power up to
10 kV with usage of the capacitor Со of capacity 2,5 µF.
The oscillograms of the discharge current and voltage and
also the signals from external capacitive probes are shown
in Fig. 2.
The analysis of the oscillograms of the discharge
current and voltage shows, that on an initial state of the
discharge development during 12 µs the large resistance
of the discharge is realized, that is the result of the
formation of the electrical double layer. According to the
oscillograms from the external capacitive probes the
double layer originally is localized in the interelectrode
region. Thus, the electron beam, which is formed in the
double layer, some part of its energy transmits to plasma
of the discharge interspace. The remaining energy is
provided for the anode. After 6 µs after the discharge
beginning the double layer moves in the near anode
region on distance about 10 cm from the anode. It is
shown by appearance of the negative voltage on the
distant external capacitive probe (oscillogram V1). After
3 µs the double layer moves to the surface of the anode
(the signals on probes V2, V3, V4 synchronously grow up.).
Here it is located up to the end of the discharge phase
with large resistance. The current of the electron beam
during a pulse increases from several hundreds amperes
up to 2,5 kA. Thus its energy decreases from 10 keV up to
4 keV. One can see the small difference between the
maximum current value of M - discharge (Im) and peak
current of the inductive discharge (Iof): Im = 0.8 Iof and
also rather large duration of existence of M - discharge
(about 12 µs) and high conversion coefficient of the
energy, accumulated in the capacitor, in the energy of the
electron beam (at a level 75 %). The mean power of the
beam equals 107 W and mean power density on unit of
the surface of the anode– 1.7⋅106 W/cm2. The general
energy, which is provided for the surface of the anode -
target during one pulse, is about 100 J.
Thus, the preliminary experiments with the
experimental sample of the plasma source of the electrons
have shown the high efficiency of the selected type of the
discharge and built device.
CONCLUSIONS
Perspective of use of an extended plasma diode of low
pressure as an intensive source of an electron beam was
shown on the basis of the carried out experimental
examinations. The feature of operation of such diode is
128
Fig.1. The general view of the experimental sample of the plasma source of the electrons
4
A–T, 6C
2
7
3
5
1
the excitation of the self-maintained beam-plasma
discharge in it with forming of a double electrical layer of
a space charge and generation of an intensive electron
beam in a discharge gap.
It was determined that at use of such plasma electron
source for magnification of a efficiency of conversion of
an exterior electric field energy into the energy of an
electron beam it is necessary to excite the self-maintained
beam-plasma discharge of М-type with near anode double
layer. In this case electrons, accelerated in a double layer,
will get at once on an anode. Thus losses of electron beam
energy on interaction with discharge gap plasma are
practically eliminated.
For forming of the М-discharge with near anode
double layer in a plasma electron source the execution of
the following requirements is necessary:
• The plasma of a discharge gap should have a gradient
of concentration with a minimum at the anode;
• The peak current of the power supply must in 5 … 10
times exceed a current, which can transfer a plasma
filament in the field of a minimum of concentration;
• The primary plasma filament should occupy the whole
section of a discharge tube;
• The diameter of a discharge tube should ensure
flowing of a working current in view of 100 % of
working gas ionization;
• In a dielectric discharge tube leaking of working gas
should be carried out from the cathode side, and
pumping-out - from the part of an anode.
Authors have designed and created the experimental
model of a plasma electron source which is calculated on
generation of an electron beam with energy 104…105 eV
at a current 2…3 kA, current density 200…300 A/см2,
pulse duration 1…10 μsec and efficiency of conversion of
an exterior electric field energy into an electron beam
energy up to 80 %.
REFERENCES
1. Lutsenko E.I., Sereda N.D., Tseluyko A.F.
Independent beam-plasma discharge. // Pis’ma
ZhTPh. –1987. –V.13, N 5. –P. 294–198.
2. Granovsky V.L. Electric current in gas. A steadied
current. – M.: Nauka. –1971. –544 p.
3. Lutsenko E.I., Sereda N.D., Tseluyko A.F. Dynamic
characteristics of the independent beam-plasma
discharge. // UFZh. –1988. –V. 33, N 5. –P. 730–736.
4. Lutsenko E.I., Sereda N.D., Tseluyko A.F., Bizukov
А.А. High-current double layer on the front of the
cathode sports. // Pis’ma ZhTPh. –1984. –V.10, N.22.
–P. 1349–1353.
5. Lutsenko E.I., Sereda N.D., Tseluyko A.F. Dynamic
double layers in the high-current diodes. // ZhTPh. –
1988. –V. 58, N 7. –P. 1299–1309.
6. Lebedev P.M., Onishchenko I.N., Tkach Yu.V.
Theory of the beam-plasma discharge. // Plasma
Physics. –1976. –V2, №3. –P. 407–413.
Fig. 2. Formation of М–discharge in the experimental
sample of the plasma source of the electrons
I
d
is the discharge current, V
1
, V
2
, V
3
, V
4
are the
signals from the external capacitive probes, placed,
accordingly, on 30, 35, 40 and 45 cm from the
cathode; V
d
is the voltage on the electrodes.
p = 10–4 Torr, V
0
= 10 kV
V
d
, kV
V
1
, kV
V
3
, kV
V
4
, kV
I
d
, kA
V
2
, kV
µs
A.F. Tseluyko, D.V. Zinov’ev, V.N. Borisko, V.A. Tseluyko, А.А. Drobishevskaya
Kharkov National University, 61108, 31 Kurchatov Av., Kharkov, Ukraine,
E-mail: Borisko@pht.univer.kharkov.ua
Conclusions
|
| id | nasplib_isofts_kiev_ua-123456789-79277 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-11-30T10:31:54Z |
| publishDate | 2002 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Tseluyko, A.F. Zinov’ev, D.V. Borisko, V.N. Tseluyko, V.A. Drobishevskaya, A.A. 2015-03-30T09:17:16Z 2015-03-30T09:17:16Z 2002 The formation of near anode double layer in highcurrent plasma diode of low pressure / A.F. Tseluyko, D.V. Zinov’ev, V.N. Borisko, V.A. Tseluyko, A.A. Drobishevskaya // Вопросы атомной науки и техники. — 2002. — № 5. — С. 127-129. — Бібліогр.: 6 назв. — англ. 1562-6016 PACS: 52.40.Hf https://nasplib.isofts.kiev.ua/handle/123456789/79277 A plasma electron source on the basis of a pulse plasma diode of low pressure with an extended interelectrode gap has been experimentally investigated. The basis of a plasma electron source serves a gas discharge of a new type - selfmaintained beam-plasma discharge, which distinctive feature is the forming of a double electrical layer of a space charge in a discharge gap and generation of an intensive electron beam. The exterior parameters were determined, at which formation of a double layer and the acceleration of an electron beam in such discharge occurs immediately at working area of the anode. The plasma electron source is calculated on generation of an electron beam with the energy 〖10〗^4…〖10〗^5 eV at the current 2…3 kA, current density 200…300 A/cm 2 , pulse length 1…10 μs and efficiency of conversion of an exterior electric field energy into an electron beam energy up to 80%. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Low temperature plasma and plasma technologies The formation of near anode double layer in highcurrent plasma diode of low pressure Article published earlier |
| spellingShingle | The formation of near anode double layer in highcurrent plasma diode of low pressure Tseluyko, A.F. Zinov’ev, D.V. Borisko, V.N. Tseluyko, V.A. Drobishevskaya, A.A. Low temperature plasma and plasma technologies |
| title | The formation of near anode double layer in highcurrent plasma diode of low pressure |
| title_full | The formation of near anode double layer in highcurrent plasma diode of low pressure |
| title_fullStr | The formation of near anode double layer in highcurrent plasma diode of low pressure |
| title_full_unstemmed | The formation of near anode double layer in highcurrent plasma diode of low pressure |
| title_short | The formation of near anode double layer in highcurrent plasma diode of low pressure |
| title_sort | formation of near anode double layer in highcurrent plasma diode of low pressure |
| topic | Low temperature plasma and plasma technologies |
| topic_facet | Low temperature plasma and plasma technologies |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/79277 |
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