Download - ICRF scenarios for ITER’s half-field phase
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 1/34
ICRF scenarios for ICRF scenarios for ITER’s half-field phaseITER’s half-field phase
E. Lerche, D. Van Eester and JET-EFDA contributorsE. Lerche, D. Van Eester and JET-EFDA contributors
19th Topical Conference on RF power in Plasmas, Newport 201119th Topical Conference on RF power in Plasmas, Newport 2011
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 2/34
ICRF scenarios for ITER’s half-field phase
E. Lerche1, D. Van Eester1, J. Ongena1, M.-L. Mayoral2, T. Johnson3, T. Hellsten3, R. Bilato4, A. Czarnecka5, R. Dumont6, C. Giroud2, P.
Jacquet2, V. Kiptily2, A. Krasilnikov7, M. Maslov8, V. Vdovin9 and JET EFDA Contributors*
JET-EFDA, Culham Science Centre, Abingdon, OX14 3DB, UK
1 LPP-ERM/KMS, Association Euratom-‘Belgian State’, TEC Partner, Brussels, Belgium2 Euratom-CCFE Fusion Association, Culham Science Centre, UK
3 Fusion Plasma Physics, Association Euratom-VR, KTH, Stockholm, Sweden4 Institut für Plasmaphysik (MPI)-Euratom Association, Garching, Germany
5 Institute of Plasma Physics and Laser Microfusion, Warsaw, Poland6 CEA(IRFM)-Euratom Association, Saint-Paul-lez-Durance, France
7 SRC RF Troitsk Institute for Innovating and Fusion Research, Troitsk, Russia8 Centre de Recherches en Physique des Plasmas, Association EURATOM-Conf. Suisse, Lausanne, CH
9 RNC Kurchatov Institute, Nuclear Fusion Institute, Moscow, Russia
*See the Appendix of F. Romanelli et al., paper OV/1-3, IAEA Fusion Energy Conference, Daejeon, 2010
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 3/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 4: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/4.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 4/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 5: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/5.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 5/34
ITER half-field H plasmas (L-mode)
Plasma: ~80%H, (He3) , 2%Be, …
B0=2.65T, IP=7.5MA (L-mode)
Auxiliary power:• 16.5MW H-NBI (elec/ion = 80/20)• 15.0MW ECRH• 10MW ICRH (elec/ion = 50/50)
n 3x1019/m3
T 8-10keV
ASTRA [A.Loarte, P.Lamalle]
ICRH (?)
L1
L2
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 6/34
ICRF scenarios for ITER at B0=2.65T
N=1 H
N=2 He3
(N=2 D)N=3 D
N=1 H (~40MHz)
N=2 3He (~53MHz)
(either H or 4He plasmas)
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 7/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 8: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/8.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 8/34
N=
1
HN
=2
D
N=
2
He3
N=
1
He3
N=
2
He3
N=
3
DN=
2
DN
=1
H
JET experiments in H plasmas at B0=2.65T
ITER ITER
N=
1 H
N=
2 3
He
JET JET
N=1 H majority ICRH [f=42MHz, Bo=2.65T]
N=2 3He ‘minority’ ICRH [f=51MHz, Bo=2.65T]
![Page 9: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/9.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 9/34
• B0=2.65T (ITER), IP=1.5MA (<<ITER)
• Similar Ne but lower T than ITER
• ICRF power up to 6MW (ITER 10MW)
• NBI: D-beams instead of H-beam (ITER non-active phase)
L2L1=L2
JET
L1
JET experiments in H plasmas at B0=2.65T
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 10/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 11: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/11.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 11/34
N=1 Hydrogen majority ICRH (f=42MHz)
N=
1
HN
=2
D
H
e-
Initial remarks:
• Low absorptivity scenario
• Electron absorption dominant
• No He3 !
N=
2
He3
N=
1
He3
TOMCAT #79332: B=2.67T, f=42.50MHz
Pow
er a
bsor
ptio
n
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 12/34
Typical N=1 H pulse (f=42MHz)
JPN 79335
• Weak energy response to RF power step (low absorbtivity)
• Considerable radiation losses (Prad / PICRH ≈ 1/3)
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 13/34
ICRF Heating efficiency
RF Power absorption
electrons
ions
elecs
ions = 0.3-0.4
Heating efficiency increases
with plasma temperature
(KK3)
(CXRS)
TOMCAT
electrons
ionsAbs
orbe
d po
wer
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 14/34
PICRH dependence
1 PINI = 1.3MW NBI2 PINIs = 2.6MW NBI
~0.1keV/MW ~0.1keV/MW
TeTi
Poor performance compared
to similar (H)-D ICRF expts.
(H)-D (JET)
~1keV/MW
Central temperatures
B0=2.7T
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 15/34
RF acceleration (NPA)
Horizontal neutral particle analyzer (KR2)
PRF=2.5MW PRF=5MW
H
H
• No clear effect of ICRF on D distribution
• (Hints of fast H with E~200keV in KF1)
Very modest tails if compared with minority ICRH experiments
SKIP if NEEDED
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 16/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 17: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/17.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 17/34
N=2 He3 ICRH (f=51MHz)
N=
2
He3
N=
3
DN=
2
DN
=1
H
Initial remarks:
• Low absorptivity scenario
• Largely dominant electron heating at low X[He3]
• Ion heating enhanced for higher X[He3]
• D-beams: N=2 / 3 parasitic absorption
TOMCAT
X[3He]=5%
#79357: B=2.66T, f=51.50MHz
Pow
er a
bsor
ptio
n
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 18/34
Typical N=2 He3 pulse
JPN 79359
elec elec + ion
~4MW
~2MW
X[He3]
RTC
• X[3He]<20%: only elec heating
• X[3He]>20%: elec + ion heating
• Large radiation losses (Prad / PICRH ≈ 1/2)
4Hz
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 19/34
JPN 79359
nkTe+nkTi
Global heating efficiency (Wpla)
• 2x larger heating efficiency at X[3He]=20% (w.r.t. 5-10%) • Efficiency increase is due to enhanced ion absorption
ICRF heating efficiency
TOMCAT
elecsionstotal
Abs
orbe
d po
wer
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 20/34
X[He3] dependence (2 PINIs , PICRH ~ 2.5MW)
• (Equilibrium) plasma energy and
temperature increase with X[3He]
(PICRH ~ 2.5MW)Overall performance increase
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 21/34
PICRH dependence (1 PINI, X[He3]=10-18%)
~0.25keV/MW ~0.2keV/MW
TeTi
Central temperatures
(H)-D (JET)
~1keV/MW
• Better performance than N=1 H maj. expts.
• Poor performance compared to similar
(H)-D ICRF expts.
B0=2.7T
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 22/34
RF acceleration (NPA)
Horizontal NPA (KR2)He3
D
• Dominant 3He RF acceleration for E<160keV
• Dominant (N=3) RF acceleration of D (beam) ions for E>160keV[V.Kiptily, to appear in PPCF]
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 23/34
Impurities: N=1 H vs. N=2 He3
Bolom
Be
0 1 2 3 4 5 6
0
2
4
6
8
N=2 He3N=1 H
I/n
2 e (1
0-2
2 Ph
*m2 /s
*sr
)
PICRH
(MW)
Ni 26 (KT7D)
Ni
Higher impurity content in N=2 3He discharges
[A.Czarnecka, to appear in PPCF]
0 1 2 3 4 5 60
1
2
3
4
5
6N=2 He3N=1 H
C 4 (KT7D)
I/n2 e (1
0-2
0 P
h*m
2 /s *
sr)
PICRH
(MW)
0 1 2 3 4 5 60,0
0,5
1,0
1,5
2,0N=2 He3N=1 H
C 6 (KT7D)
I/n2 e (1
0-2
0 P
h*m
2 /s *
sr)
PICRH
(MW)
C6 C4 • Higher radiation from plasma edge / divertor
• Confirmed by 2D bolometric tomography
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 24/34
Summary of JET experiments
N=1 H ICRH
N=2 He3 ICRH
• Low heating efficiency ( = 0.15 – 0.4, increasing with X[He3])• Largely dominant electron heating for low X[He3] (mainly LD + TTMP) • Ion absorption proportional to X[He3]: dominant for X[He3] > 20% • Fast He3 (up to 250keV) detected by NPA
• Clear parasitic D absorption with PNBI>5MW
• Poor global heating: ~0.2keV/MW
• Strong plasma-wall interaction (Prad/PICRH ≈ 1/2, impurities, etc…)
• Low heating efficiency ( = 0.3 - 0.4)
• Dominant electron heating: pe 2 x pi (LD + TTMP)
• Modest H acceleration (up to 50keV) registered by NPA• Negligible parasitic N=2 D absorption• Poor global heating: ~0.1keV/MW
• Considerable plasma-wall interaction (Prad/PICRH ≈ 1/3)
![Page 25: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/25.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 25/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 26: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/26.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 26/34
Preliminary ITER modelling
• Objectives:
- Intuitive picture of relative RF absorptivity (SPA) of the various heating scenarios
- Parametric scans for preliminary optimization
• More ‘rigorous’ numerical efforts
[R. Budny, IAEA2010, to appear in NF2011]
1D TOMCAT code
[Van Eester, PPCF98]
![Page 27: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/27.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 27/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 28: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/28.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 28/34
• E+ 0 @ =H (‘screening’)
• Low absorptivity scenario (= 0.3 - 0.4)
• Dominant electron heating (broad absorption)
• Higher TH helps ion absorption
• Possible 3He absorption (if present)
E+ electric field
=
H
Fundamental H majority ICRH (42MHz)
TH 8keV
TH 25keV
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 29/34
• Higher TH yields higher absorption (ions)
• Higher ne yields higher absorption (elecs)
• pe = pi @ TH 20keV
Parametric scan
L-mode 2: T =8/10keVn=34 (00)
ITER ITER
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 30/34
• Larger E+ at =2He3
• Low absorptivity scenario (= 0.25 - 0.4)
• Dominant electron heating (broad absorption)
• Ion heating enhanced at higher X[3He]
• Possible N=1 H (N=2,3 D) absorption
N=2 3He ‘minority’ ICRH (53MHz)
=
H
=2He3
X[3He]=4%
X[3He]=25%
E+ electric field
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 31/34
• Higher X[3He] yields higher absorption (ions)
• Higher ne yields higher absorption (elecs)
• pe = pi @ X[3He] 30%
Parametric scan
L-mode 2: T =8/10keVn=34 (00)
ITER ITER
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 32/34
Do we have an ICRH scenario for H plasmas?
N=2 H majority ICRH at 1/3 nominal field (B0=1.8T)
N=2 H
(N=3 D)
E+ electric field
pH = 70%
pe = 30%
• Full single-pass absorption (=1) • Dominant ion heating• But ECRH out of range, confinement (?)• Could be used for fast particle studies
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 33/34
Outline
- Motivation ICRF scenarios for initial operation phase of ITER (non-activated, half-field)
- Summary of main results of JET experiments (H plasmas)
N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
- Preliminary modelling of half-field ICRH scenarios
H plasmas: N=1 H majority ICRH
N=2 3He ‘large minority’ ICRH
4He plasmas: (Standard) N=1 H ‘minority’ ICRH Impact of H concentration (H-pellet’s)
- Summary & Discussion
![Page 34: ICRF scenarios for ITER’s half-field phase](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568147a6550346895db4e361/html5/thumbnails/34.jpg)
19th Topical Conference on RF Power in Plasmas, Newport, 2011 34/34
N=1 H–4He minority ICRH (42MHz)
• Good absorption scenario (= 0.7 – 1.0)
• Dominant ion heating (for moderate X[H])
• Ion absorption decreased at higher X[H]
n=34 (00) L-mode 2 E+ electric field
=
H
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 35/34
N=1 H–4He minority ICRH (42MHz)
L-mode 2: T =8/10keV L-mode 1: T =4/5keV
• Ion absorption is reduced at higher X[H] (‘screening effect’)
• This effect is stronger at lower temperatures (L-mode 1):
• Operating at high k// phasing (00) helps
• Accounting for tail formation does not alter the behaviour at high X[H]
• No MC absorption (1D and 2D)
n=34 (00) n=34 (00) n=60 (0)
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 36/34
N=1 H–4He minority ICRH (42MHz)
Comparison with 2D wave codes
• Electron absorption slightly overestimated in 1D calculations
• Unlike for the H plasmas (touchy), for the better absorbing (H)-D scheme 2D calculations are converged
EVE code [R.Dumont, NF2009]
X[H]=5% X[H]=45%E+ E+
PabsPabs
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 37/34
SPA vs. heating efficiency
JET
pla=0.5 loss=0.1
Simple multi-pass model
Pow
er
ITER
(H plasmas)
(4He plasmas)loss=0
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19th Topical Conference on RF Power in Plasmas, Newport, 2011 38/34
N=1 H majority ICRH
N=2 3He–H ICRH
• Moderate absorptivity (~0.5) → significant PWI? [seen in JET]
• Dominant electron heating [seen in JET]
• Increasing temperature favours ion heating [seen in JET] but pe=pi @ 25keV
• Increasing density favours overall heating (electron heating dominant)
• Low absorptivity (~0.3) significant PWI? [seen in JET]
• Largely dominant electron heating except for high X[He3] [seen in JET]
• Increasing X[He3] favours ion heating [seen in JET] but pe=pi @ X[He3]~30%
• Increasing temperature has small effect
• Increasing density favours overall heating (electron heating dominant)
Summary of ITER modelling
N=1 H-4He ICRH
• Good single-pass absorption (0.7) with dominant ion heating (X[H]<25%)
• ICRF efficiency lower for larger X[H], partic. at lower temperature (L mode-1)
• This effect can be compensated with higher k// phasing (00)
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H plasmas:
• Both ICRF scenarios proposed for ITER’s half field phase in H suffer from low power absorptivity with dominant electron heating:
- N=1 H majority requires high plasma temperatures
- N=2 3He requires large X[3He] for efficient ion heating
• This DOES NOT mean that they are not suited for the commissioning of the ICRF system, but the power may be limited (enhanced PWI)
• One possible ICRF scenario with good ion absorption is N=2 H majority at 1/3 of the nominal B0 (but ECRH is out of range)
4He plasmas:
• (H)-4He minority ICRH is OK for moderate X[H] (<40%)
• At higher X[H] the ion absorption is jeopardized, particularly at low T
• Operating at higher k// phasing (e.g. 00) helps recovering good absorption in general (but lower coupling)
Final remarks
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Wave modelling:
• Low absorption H-plasma scenarios require further modelling (touchy!)
• (H)-4He ICRF scenario well converged but further simulations at high X[H] welcome
Integrated scenario modelling:
• Use experimental heating efficiencies / SPA’s obtained for assessing which T can actually be expected in ITER’s half-field H-plasma phase
• Use realistic power absorption profiles in all cases (broader elec. absorption)
Final remarks
Experiments:
• High X[H] ICRH experiments in 4He plasmas (B0=2.65T, f=42MHz)
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Discussion
JET ITER (prelim.)
N=1 H ICRH
• Low heating efficiency (= 0.3-0.4)
• Electron heating dominant (pe/pi=2)
• Pre-heating helps overall absorption
• Considerable plasma-wall interaction
• Reasonable heating efficiency (= 0.5)
• Electron heating dominant except for TH>40keV
• Higher ne and higher Te enhance absorption• ??
N=2 He3 ICRH
• Low heating efficiency (= 0.15-0.45) depending on X[He3]
• Elec. heating dominant for low X[He3]; • Ion heating dominant for X[He3]>20%
• NBI pre-heating helps (but parasitic D absorption)
• Strong plasma-wall interaction
• Low heating efficiency (= 0.2-0.4) depending on parameters • Electron heating dominant throughout
• Higher X[He3], higher ne or higher Te enhance overall efficiency:
• ??
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EXTRAS
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Impurities: N=1 H vs. N=2 He3 (KS3)
Bolom Zeff
Be
0 1 2 3 4 5 6
0
2
4
6
8
N=2 He3N=1 H
I/n2 e (
10-2
2 P
h*m
2 /s *
sr)
PICRH
(MW)
Ni 26 (KT7D)
0 1 2 3 4 5 60
1
2
3
4
5
6N=2 He3N=1 H
Cr 22 (KT7D)
I/n
2 e (1
0-2
2 Ph
*m2 /s
*sr
)
PICRH
(MW)
Ni Cr
Higher impurity content in N=2 3He discharges
[A.Czarnecka, to appear in PPCF]
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Impurities: N=1 H vs. N=2 He3 (KT2/7)
VUV spectroscopy (KT2/KT7)
N=1 H
N=2 3He
0 1 2 3 4 5 60
1
2
3
4
5
6N=2 He3N=1 H
C 4 (KT7D)
I/n
2 e (1
0-2
0 Ph
*m2 /s
*sr
)
PICRH
(MW)
0 1 2 3 4 5 60,0
0,5
1,0
1,5
2,0N=2 He3N=1 H
C 6 (KT7D)
I/n
2 e (1
0-20 P
h*m
2 /s *
sr)
PICRH
(MW)
C6 C4
• Higher radiation losses in N=2 3He scenario come from plasma edge / divertor
• Confirmed by 2D bolometric tomography
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coax • Larger k// yields higher absorption
• pe / pi roughly independent of k//
Effect of antenna phasing
coax
[A. Messiaen NF2010]
Fundamental H majority ICRH (42MHz)
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• Low X[3He]:
Larger k// yields higher
absorption (elecs only)
X[3He]=4%
X[3He]=30%
coax
Effect of antenna phasing
Fundamental H majority ICRH (42MHz)co
ax
• High X[3He]:
Low k// → ion heating
Large k// → elec. heating
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Effect of H dillution (4He contamination)
N=1 H majority ICRH
Preliminary modelling shows same tendency (but weaker)
Important to re-assess experimentally
X[4He] X[4He]
(PICRF=5MW)
no NBI1 PINI
no NBI1 PINI
Wdia NPA on H
Plasma dilution
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RF acceleration (NPA)
Horizontal NPA (KR2)3He
D
• Relatively modest acceleation of 3He ions (E<160keV) (hints on KF1 E<260keV)• Clear RF acceleration of D (beam) ions above beam source energy
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RF acceleration (ion losses)
Scintillator probe (KA3)
• Main losses come from RF accelerated D beam ions
• Small fast 3He losses (No hints fast 3He detected by -spectroscopy)
t=46s
D
3He
[V.Kiptily]
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Simple comparison with other scenarios
H minority in D (ILA)
PICRH(MW)T
(ke
V)
~1keV/MW
N=1 D majority (B0=3.3T, f=25MHz)
~0.5keV/MW
N=1 H majority
T/P 0.1keV/MW
N=2 He3
T/P 0.2keV/MW