Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2000
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| Cite this: | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations / I.S. Bondarenko, A.A. Chmyga, N.B. Dreval, S.M. Khrebtov, A.D. Komarov, A.S. Kozachok, L.I. Krupnik, L.G. Eliseev, V.A. Mavrin, A.V. Melnikov, K.A. Rasumova, L.G. Zimeleva, C. Hidalgo, I. Garcia-Cortes, P. Coelho, M. Cunha, B. Goncalves, A. Malaquias, I.S. Nedzelskiy, C.A.F. Varandas // Вопросы атомной науки и техники. — 2000. — № 6. — С. 178-180. — Бібліогр.: 7 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859655215112781824 |
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| author | Bondarenko, I.S. Chmyga, A.A. Dreval, N.B. Khrebtov, S.M. Komarov, A.D. Kozachok, A.S. Krupnik, L.I. Eliseev, L.G. Mavrin, V.A. Melnikov, A.V. Rasumova, K.A. Zimeleva, L.G. Hidalgo, C. Garcia-Cortes, I. Coelho, P. Cunha, M. Goncalves, B. Malaquias, A. Nedzelskiy, I.S. Varandas, C.A.F. |
| author_facet | Bondarenko, I.S. Chmyga, A.A. Dreval, N.B. Khrebtov, S.M. Komarov, A.D. Kozachok, A.S. Krupnik, L.I. Eliseev, L.G. Mavrin, V.A. Melnikov, A.V. Rasumova, K.A. Zimeleva, L.G. Hidalgo, C. Garcia-Cortes, I. Coelho, P. Cunha, M. Goncalves, B. Malaquias, A. Nedzelskiy, I.S. Varandas, C.A.F. |
| citation_txt | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations / I.S. Bondarenko, A.A. Chmyga, N.B. Dreval, S.M. Khrebtov, A.D. Komarov, A.S. Kozachok, L.I. Krupnik, L.G. Eliseev, V.A. Mavrin, A.V. Melnikov, K.A. Rasumova, L.G. Zimeleva, C. Hidalgo, I. Garcia-Cortes, P. Coelho, M. Cunha, B. Goncalves, A. Malaquias, I.S. Nedzelskiy, C.A.F. Varandas // Вопросы атомной науки и техники. — 2000. — № 6. — С. 178-180. — Бібліогр.: 7 назв. — англ. |
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| container_title | Вопросы атомной науки и техники |
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UDC 533.9
178 Problems of Atomic Science and Technology. 2000. № 6. Series: Plasma Physics (6). p.178-180
DEVELOPMENT OF THE HEAVY ION BEAM PROBING DIAGNOSTIC
AND NEW RESULTS IN THE PLASMA ELECTRIC POTENTIAL
INVESTIGATIONS
I.S.Bondarenko, A.A.Chmyga, N.B.Dreval, S.M.Khrebtov, A.D.Komarov, A .S.Kozachok,
L.I.Krupnik
Institute of Plasma Physics, NSC”KIPT”, Kharkov, UKRAINE
L.G.Eliseev, V.A,Mavrin, A.V.Melnikov, K.A.Rasumova, L.G. Zimeleva
Institute of Nuclear Fusion, RRC “Kurchatov Institute”, Moscow, RUSSIA
C.Hidalgo, I.Garcia-Cortes
Asociacion EURATOM/CIEMAT, para Fusion, Madrid, SPAIN
P.Coelho, M.Cunha, B.Goncalves, A.Malaquias, I.S.Nedzelskiy, C.A.F.Varandas
Associacao EURATOM/IST, Centro de Fusao Nuclear, Instituto Superior Tecnico, Lisboa
PORTUGAL
Introduction
A heavy ion beam probe (HIBP) diagnostic is a uniq-
ue tool for plasma research in fusion facilities. It has
been successfully realized up to now on a number of
devices with magnetic confinement ranging from
tokamaks and stellarators to variety mirrors. In
principle, the HIBP method gives an opportunity to
measure simultaneously a few plasma parameters as
well as their fluctuations with high temporal and spatial
resolution They are an electric potential Φpl, electron
density ne, electron temperature Te, and a poloidal
magnetic field component Bp[1]. The measurements of
Φpl and radial particle flux Γr have been successfully
made in previous HIBP experiments [2]. Other
parameters measured by this diagnostic (ne profiles,
poloidal magnetic field, magnetic fluctuations and
electron temperature Te(r)) have been investigated in
rather uncommon cases and developed not so good. The
specific feature of the HIBP diagnostic is that each
HIBP equipment is faced with its own unique set of
hardware related to the type of the fusion facility, its
size, configuration and strength and topography of the
magnetic field. Installation of a probing beam at a new
facility requires a new development of a diagnostic
hardware and preliminary computer simulations.
A new HIBP equipments
An advanced HIBP diagnostic equipments were
developed and manufactured for TJ-II stellarator (Spain,
Madrid) [3] and tokamak TUMAN-3M.(St.
Petersburg, Russia) [4] .
A 200 keV heavy ion beam probing equipment has
been developed for the TJ-II flexible heliac to measure
of plasma electric potential and density profiles as well
as the fluctuation characteristics of these parameters.
Traditional engineering composition of this equipment
consists of two parts: injector of primary probing beam
and energy analyzer of secondary particles. The
advantage of TJ-II HIBP system is in simultaneous
utilization of two different detection systems for the
secondary ions - 300 Proca-Green electrostatic energy
analyzer and multiple cell array detector (MCAD). The
Fig 1. TJ-II HIBP photograph and setup
schematic diagram and the photograph of the HIBP
installation on TJ-II are shown in Fig.1.
In the system developed for TUMAN-3M is used
new detection system with secondary electrons
suppression.
These innovative designs aim to spread and improve
the HIBP capabilities in simultaneous measurements of
plasma parameters. Now these two new diagnostic
equipments started in operation.
Initial operation of HIBP on TJ-II
HIBP experiment has been started with probing beam
passing through all magnetic fields and investigated
plasma. However, a strong HX-rays were detected when
120 keV Cs+ beam was injected into TJ-II. The creation
179
of HX-rays is attributed to the runaway electrons
appeared during ramp-up phase of the toroidal magnetic
field. This effect always accompanied plasma discharge
in TJ-II when vacuum conditions were worse then
1×10−7 torr. Diagnostic beam could complementary
stimulate HX-ray due to ionization of the residual gas
and knocked of the wall of the TJ-II vacuum vessel. The
problem was vanished with an special oven-door, which
pushed into discharge chamber in time and additional
remote controlled Faraday-like target introduced across
the beam at the exit of acceleration tube during toroidal
field ramp-up.
Though the loading of the analyzer split detector by
plasma radiation seems not to be a serious problem
(especially with a new modified bias split detector,
mentioned above), it still exist for the operation of
MCAD, because of much more close arrangement to the
plasma.
Fig.2. Time traces of some discharge parameters
Fig.2 presents a trace of beam signal in the
secondary beam line tube. Experiment has been made
with full set of TJ-II magnetic fields and without plasma
in chamber. The behavior of signal demonstrates
passing of a primary Na+ and K+ ions into analyzer-
connected tube in time of increasing and decreasing of
the magnetic fields (in initial Cs+ probing beam there
are up to 15% impurity alkali ions). Small signal at the
moment of gas puffing could be attributed to secondary
Cs++ ions formed in collisions with gas target. Future
experiments and detail comparison with calculation
must improve these results.
Behavior of the plasma electric potential during
the internal and external transport barriers
formation
The plasma potential profile was measured on the T-
10 tokamak (R = 150 cm, a = 30 cm) by HIBP
diagnostics in the regimes with the external (H-mode)
and internal transport barriers (ITB). The diagnostic Tl+
beam with the energy up to 250 keV and intensity of
about a few dozens µA was used to probe the outer half
of the plasma column in the low field side.
This paper reports the HIBP study of the regimes
with electron ITB obtained by off-axis ECRH/ECCD
(140 GHz, 0.5-0.8 MW) with B = 2.1 - 2.14 T, Ip = 200 -
330 kA, qlim = 2.4 [5]. We investigate the extra potential
values with respect to initial steady state phase (L-
mode). The time evolution of the extra potential profile
was obtained by the periodical scan of the beam
injection angle. The power supply system provides the 7
ms scan every 20 ms.
In the previous experiments we have investigate
the regime with the external transport barrier (H-mode)
B = 2.28 T, Ip = 160 kA, àlim = 25 cm, qlim = 3. It was
shown that during the L-H transition the peripheral
plasma potential forms narrow layer with strong electric
field (~300 V/cm) in the vicinity of the limiter [6].
4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0
-400
0
400
t, m s
ρρρρ = 0 .73φ φφφ ,
V
1 0
15
7 P E C = 0 .5 M W
B o lo m .
W
W
, k
J
1 .2
1 .4
n e, 1
013
c
m-3
D αααα
n e
0
5 0
1 0 0
1 5 0
B
o
l.,
k
W
0
2
4
D
α ααα
, a
. u
.
Fig.3. Time traces of some plasma parameters
Figure 3 shows the time evolution of the plasma
parameters in the in with H-mode in comparison with
the reference one. One can see that the fall of the plasma
potential occurs simultaneously with the typical H-mode
features: increase of the line-averaged density and fall
of Dα emission. The local potential in the observed point
with r = 18 cm falls down simultaneously with increase
of ne and fall of Dα. The observed sample volume was
located in between the edge barrier (r = 23-24 cm) and
the region of EC resonance (r = 14 cm). The local
plasma potential in the inner point correlates with
Dα intensity: Dα and potential rises up and falls
down similarly.
19 20 21 22 23 24 25
-500
-400
-300
-200
-100
0
∆
φ
∆
φ
∆
φ
∆
φ ,
V
#23724
r, cm
t=735 ms L-mode
t=854 ms
t=874 ms H-mode
Fig.4. The temporal evolution of the potential profiles
180
Figure 4 presents the typical time evolution of the
extra potential profile in the L-H transition with respect
to the L-mode level. The narrow layer (width about 1.5
cm) with a strong electric field is formed just near the
limiter. The potential fall is about -400 V.
Fig. 5. The electron temperature profiles (a) and the
plasma potential (b)
Figure 5a shows the Te profiles measured both by
Thomson scattering and ECE methods after and before
the transition. It shows the formation of the steep
gradient on the Te profile at the region of EC resonance
(r~16 cm). Figure 5b shows the time evolution of the
potential profile. During the electron ITB formation the
plasma extra potential forms the transient local deep
negative well with maximum value up to -1000 V in the
vicinity of the internal barrier. This local well
disappears in the post-barrier steady state.
Fig. 6. The temporal evolution of the plasma potential
The reference values were found at the initial steady-
state phase. The presented profile was obtained as the
combinations of the two parts measured in two similar
discharges with the beam energies Eb=240 keV and
Eb=210 keV. The observed radial intervals overlap in
about 1 cm.
It was shown in [5] that in the discussed regimes the
electron ITB formation correlates with potential fall,
drop of Dα and increase of line-averaged density ne.
The area of observation was limited by the diagnostic
restrictions. To observe the outer part of the plasma the
beam energy was changed to Eb=170 keV.
The temporal evolution of the outer part of the
plasma potential profile in the shot #26176 with ITB is
presented in Fig. 6. The area of the sharp decrease of the
plasma potential just near the limiter appears to be
similar to the one shown in Fig. 4.
During the edge and internal transport barriers
formation the local potential near both barriers behave
similar: when the density rises up the potential falls
down, when the density keeps constant the potential
rises up, the post-barrier steady-state extra potential
profile with respect to the pre-barrier steady state has
the stair shape with a sharp jumps ∆φ ~ - 400 V near the
barriers [7].
Conclusions
1. The inter transport barrier is formed with such a
current distribution, where dq/dr=0 and q value is
placed near the resonance.
2. A deep narrow potential well occurs during the
barrier formation, which manifests the improvement of
the electron confinement in the barrier zone.
3. At qL≤ 4 values two barriers appear simultaneously.
The external barrier has the features of the L-H
transition.
References
[1] Yu.N.Dnestrovskij, A.V.Melnikov, L.I.Krupnik,
I.S.Nedzelskij. IEEE Trans.on Plasma Science,
vol.22, No.4, p.310, 1994.
[2] T.P.Crowley and the Rensselaer Plasma Dynamics
Laboratory Team. IEEE Trans. On Plasma
Sciense, vol.22, No.4, p.291, 1994.
[3] C.Alejaldre, J.Alonso, J.Botija, F.Castejon et al.
Fusion Technology, vol.17, p.131, 1990.
[4] S. V. Lebedev et al. Plasma Physics and
Controlled Fusion, vol.38, No.8, p.1103, 1996.
[5] V. V. Alikaev et al. In: 27th EPS , P2.039.
[6] A.V. Melnikov, L.G. Eliseev, Chechoslovak J.
Phys., 49, (Suppl 3S), 35 ,1999.
[7] A.V. Melnikov et al. 10th International Toki
Conference on Plasma Physics and Controlled
Nuclear Fusion (ITC-10) 2000, Book of abstracts,
p.53. Submitted to J. Plasma and Fusion Research
of Japan.
1 0 1 5 2 0
- 1 ,2
- 0 ,8
- 0 ,4
0 ,0
b
# 2 4 2 7 3 ,
E b = 2 1 0 k e V
# 2 4 2 6 4 ,
E b = 2 4 0 k e V
a f t e r I T B
f o r m a t io n
b e f o r e I T B
I T B f o r m a t i o n
r , c m
∆
φ ,
k
V
0 1 0 2 0 3 0
0
1
2
a
# 2 4 2 6 4
H IB P
l a s e r
f o r m a t i o n
B = 2 .1 4 T , I p = 2 8 0 k A , n e = 1 . 3 x 1 0 1 3 c m - 3
2 ωωωω E C E
b e f o r e I T B
a f t e r I T B
T e,
k
eV
24 25 26 27 28 29 30 31
-500
-400
-300
-200
-100
0
100
#26176 , B = 2 .14 T , I= 280 kA , n e= 1 .3x10 13 cm -3
lim ite r
E b = 170 kV
B ase=512-633m s
t633
t712
t713
t733
t773
t873
∆
φ
∆
φ
∆
φ
∆
φ ,
V
r , cm
Institute of Plasma Physics, NSC”KIPT”, Kharkov, UKRAINE
Institute of Nuclear Fusion, RRC “Kurchatov Institute”, Moscow, RUSSIA
C.Hidalgo, I.Garcia-Cortes
Asociacion EURATOM/CIEMAT, para Fusion, Madrid, SPAIN
P.Coelho, M.Cunha, B.Goncalves, A.Malaquias, I.S.Nedzelskiy, C.A.F.Varandas
A new HIBP equipments
Initial operation of HIBP on TJ-II
Fig.2. Time traces of some discharge parameters
|
| id | nasplib_isofts_kiev_ua-123456789-78541 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T13:38:39Z |
| publishDate | 2000 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Bondarenko, I.S. Chmyga, A.A. Dreval, N.B. Khrebtov, S.M. Komarov, A.D. Kozachok, A.S. Krupnik, L.I. Eliseev, L.G. Mavrin, V.A. Melnikov, A.V. Rasumova, K.A. Zimeleva, L.G. Hidalgo, C. Garcia-Cortes, I. Coelho, P. Cunha, M. Goncalves, B. Malaquias, A. Nedzelskiy, I.S. Varandas, C.A.F. 2015-03-18T18:41:03Z 2015-03-18T18:41:03Z 2000 Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations / I.S. Bondarenko, A.A. Chmyga, N.B. Dreval, S.M. Khrebtov, A.D. Komarov, A.S. Kozachok, L.I. Krupnik, L.G. Eliseev, V.A. Mavrin, A.V. Melnikov, K.A. Rasumova, L.G. Zimeleva, C. Hidalgo, I. Garcia-Cortes, P. Coelho, M. Cunha, B. Goncalves, A. Malaquias, I.S. Nedzelskiy, C.A.F. Varandas // Вопросы атомной науки и техники. — 2000. — № 6. — С. 178-180. — Бібліогр.: 7 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/78541 533.9 en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Plasma diagnostics Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations Article published earlier |
| spellingShingle | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations Bondarenko, I.S. Chmyga, A.A. Dreval, N.B. Khrebtov, S.M. Komarov, A.D. Kozachok, A.S. Krupnik, L.I. Eliseev, L.G. Mavrin, V.A. Melnikov, A.V. Rasumova, K.A. Zimeleva, L.G. Hidalgo, C. Garcia-Cortes, I. Coelho, P. Cunha, M. Goncalves, B. Malaquias, A. Nedzelskiy, I.S. Varandas, C.A.F. Plasma diagnostics |
| title | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations |
| title_full | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations |
| title_fullStr | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations |
| title_full_unstemmed | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations |
| title_short | Development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations |
| title_sort | development of the heavy ion beam probing diagnostic and new results in the plasma electric potential investigations |
| topic | Plasma diagnostics |
| topic_facet | Plasma diagnostics |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/78541 |
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