fast ion collective thomson scattering diagnostic for iter s.b. korsholm 1,2, h. bindslev 1, f....
TRANSCRIPT
Fast ion collective Thomson scattering diagnostic for ITER
S.B. Korsholm1,2, H. Bindslev1, F. Leipold1, F. Meo1, P.K. Michelsen1, S. Michelsen1, A.H. Nielsen1, E. Tsakadze1, and P.P. Woskov2
1 Association EURATOM-Risø National Laboratory, Technical University of Denmark2 MIT Plasma Science & Fusion Center
This work was supported by the European Communities under the contract of Association between EURATOM/Risø and carried out within the framework of the European Fusion Development Agreement [under EFDA Contract 04-1213 and EFDA Task TW6-TPDS-DIADEV.D2]. The views and opinions expressed herein do not necessarily reflect those of the European Commission.
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Outline of the talk
• ITER measurement requirements for confined fast ions
• Overview of the 60 GHz CTS diagnostic for ITER
• Measuring potential in alternative scenarios
• Modeling and measurements of the required HFS blanket cut-out
• Current state of design – a four mirror HFS receiver
• Robustness to misalignment
• Measurements of fuel ion ratio and bulk ion drift velocity by CTS
• Future work
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Tools developed and used in the studies
Scattering calculationsITER requirements for ’s
CEMFinite difference
code
Vertical beam properties
Gauss3D
Horizontal beam properties
Design of mirrors
Mock-up
Measured beam properties
Design of gap
Current memory
limitations
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
ITER measuring requirements for fast ions
m-3
m-3
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Schematic of the scattering geometry – LFS-BS
ki ks
k
B
(a) (b)
ki ks
k
B
ki ks
k
B
(a) (b)
The LFS-BS system resolves the perpendicular ion velocity component.
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Schematic of the scattering geometry – HFS-FS
Receiver
Probe B
ks
ki
k
Receiver beam
Probe beam
The HFS-FS system resolves the parallel ion velocity component.
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Capabilities of the 60 GHz CTS system
• Using current or near term technology, it meets ITER measurement requirements for fusion alphas
• Robust mechanically – no moveable components
• Simultaneous measurements of 10 positions for each system
• For the ELMy H-mode scenario within the engineering constraints, a previous study demonstrated:
• Requirements met at different plasma parameters
• Sufficient beam overlap in the spectral range (dispersion effects).
• Robustness of the overlap against variations of density such as sawteeth
• Robustness of the localization of the measurement against variations of density such as sawteeth
• Operation in alternative scenarios?
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Measuring potential in reversed shear scenario
Parameter Standard H-Mode Reversed shear
Bo (T) -5.3 -5.425
Ne(0) (m-3) 10.24 1019 7.27 1019
Te(0) (keV) 24.7 23.9
Rmag (m) 6.41 6.66
Zmag (m) 0.68 0.52
Ip (MA) 15 9
N 1.842 2.567
p 0.661 1.529
ITER operating scenario database
0 0.5 1 1.50
2
4
6
8
10
12
Normalized flux coordinate
Ele
ctro
n d
en
sity
(1
019 m
-3)25
Elmy H-modeReversed shear
0 0.5 1 1.50
5
10
15
20
Normalized flux coordinate
Ele
ctro
n t
emp
erat
ure
(k
eV)
http://efdasql.ipp.mpg.de/saibene/ITER_Eq_Restricted/equilibria_index.htm (password protected), Yuri Gribov, website maintained by Gabriella Saibene
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Measuring potential of HFS receiver – ELMy H-mode
4 4.5 5 5.5 6 6.5 7 7.5 8 8.50
1
2
3
4
5
6
7
8
R (m)
L/4
| || || || || |
| || || |
| || |
| || || |
| |
| |
| |
| || || |
| |
DS: 0.4DS: 0.7DS: 1.0DS: 1.2
DS: 0.4 (neo = 4.10 1019 m-3)DS: 0.7 (neo = 7.17 1019 m-3)DS: 1.0 (neo = 10.24 1019 m-3)DS: 1.2 (neo = 12.29 1019 m-3)
ITER CTS: Scenario 2 (ELMy H-mode)L is the resolving power, i.e. the system figure of merit.
L/4 ≥ 1 ⇒ 16 velocity bins
Pin = 1 MW
Integration time: 20 ms
ECE noise 200 eV
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Measuring potential of HFS receiver – reversed shear
4 4.5 5 5.5 6 6.5 7 7.5 8 8.50
1
2
3
4
5
6
7
8
R (m)
L/4
| || || || || |
| || |
| || || |
| || |
| |
| || |
| || |
| |
| |
| |
DS: 0.4DS: 0.7DS: 1.0DS: 1.2
DS: 0.4 (neo = 2.91 1019 m-3)DS: 0.7 (neo = 5.09 1019 m-3)DS: 1.0 (neo = 7.27 1019 m-3)DS: 1.2 (neo = 8.72 1019 m-3)
ITER CTS: Scenario 4 (Weakly reversed shear)
Pin = 1 MW
Integration time: 20 ms
ECE noise 200 eV
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Comparing effects of scenarios on HFS receiver - scaled ne
4 4.5 5 5.5 6 6.5 7 7.5 8 8.50
1
2
3
4
5
6
7
8
R (m)
L/4
| || || |
| |
| |
| || || |
| |
| |
Standard H-modeReversed shear (neo * 1.4)
Main cause: Different plasma location
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Modification of the LFS port plug
• Taking into account more detailed engineering constraints
• Minor changes in mirror locations ⇒ no significant changes in scattering calculations
• Small cut of the welding edge of the port plug front plate frame
HFS-FS probe 1st mirror
Plug front plate (edge region)
Plug front plate anchor point
LFS-BS Probe1st mirror
LFS-BS Probe2nd mirror
HFS-FS Probe2nd mirror
LFS-BS Horn array
LFS-BS receivermirror
Fuel Ion RatioHorn array
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Challenges of the HFS-FS receiver
• Receiver quasi-optics located behind HFS blanket modules
• Integration issues
• Spatial constraints
• Very astigmatic beams
• Detected signal transmitted in in-vessel waveguides (via upper port)
• Similar challenges to the HFS reflectometer
• Opening angle of the beam determined by height of
slit/blanket cut-out.
• Direct implication to the CTS signal
• Feasibility study: To satisfy measuring criteria
≤ 7° h = 30 mm⇒
3 4 5 6 7 8 9 10
-5
-4
-3
-2
-1
0
1
2
3
4
5
R / m
z / m
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Mock-up Mark I of the ITER HFS CTS receiver at Risø
Quasi-optical
emitterhorn
Measuring rig
Detector
emitterhorn
mirror
Emitterhorn
Blanket modules
• Non-astigmatic mirrors
• problem is split up in horizontal and vertical ⇒ two sets of mirrors
• Goals:
• verify vertical opening angle calculations
• study effect of horizontal cut-out
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Opening angle of HFS receiver beam – measurements
h = 30 mm ⇒
= 7.5° (7 °)
h = 20 mm ⇒
= 9.4° (10.5 °)
-15 -10 -5 0 5 10 15-15
-10
-5
0
5
10
15051005-25L3h30d350
Horizontal (cm)
Ver
tical
(cm
)
Wy= 38 mm
-15 -10 -5 0 5 10 15-15
-10
-5
0
5
10
15051005-27L3h20d350
Horizontal (cm)
Ver
tical
(cm
)
Wy =45 mm-15 -10 -5 0 5 10 15
-15
-10
-5
0
5
10
15051004-14L2h20d350
Horizontal (cm)
Ver
tical
(cm
)
-15 -10 -5 0 5 10 15-15
-10
-5
0
5
10
15051004-18L2h30d350
Horizontal (cm)
Ver
tical
(cm
)
Wy =90 mm
Wy= 111 mm
Distance from blanket1,1 m 1,8 m
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Blanket cut-out for the HFS receiver – top view
First Mirror
Blanket module key
Beams (extreme cases)
Blanket #3 Blanket cut-out
First Mirror
Blanket module key
Beams (extreme cases)
Blanket #3 Blanket cut-out
Width front = 580 mmWidth back = 410 mm
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Blanket cut-out for the HFS receiver – front view
Blanket Cut-out Height = 28 mmWidth front = 580 mmWidth back = 410 mm
Spacer (in yellow )= 8 mm
Vertical Gap = 10 mm
Blanket #4
Blanket #3
Blanket Cut-out Height = 28 mmWidth front = 580 mmWidth back = 410 mm
Spacer (in yellow )= 8 mm
Vertical Gap = 10 mm
Blanket #4
Blanket #3
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
ITER CTS HFS receiver mock-up Mark II - Astigmatic mirrors
• Upgrade of codes to calculate 3D astigmatic mirrors
• 2-mirror mock-up with astigmatic mirrors
• to study astigmatic beams and compare to code
• to study propagation of off-axis beams
Side view
Zoom on cut-out
Front view
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Results of ITER CTS mock-up Mark II – beam propagation
Distance from blanket: 180 cmDistance from blanket: 64 cm
-10 -5 0 5 10-30
-25
-20
-15
-10
-5
0
5
10
Distance (cm)
Dis
tanc
e(cm
)
ITER061108-02f200c41D000.txt
( xc, yc ) = ( 0.04, -9.04 )P = ( 1.00, 0.02 ), W = 2.13P = ( 0.02, -1.00 ), W = 13.43
-10 -5 0 5 10-30
-25
-20
-15
-10
-5
0
5
10
Distance (cm)
Dis
tanc
e(cm
)
ITER061108-12f200c41D000.txt
( xc, yc ) = ( -2.23, -6.98 )P = ( 0.99, 0.13 ), W = 3.64P = ( 0.13, -0.99 ), W = 4.61
Note that numbers in graphs are dimensions in 110 GHz frame (which is the frequency of source)
60 GHz frame
0 0.5 1 1.520
25
30
35
40
45
50
55
Distance (m)
Bea
m r
adiu
s(m
m)
No plate, x
W0= 20.73(mm)
Z0=1107.89(mm)
Angle= 2.40
0 0.5 1 1.520
25
30
35
40
45
50
Distance (m)B
eam
rad
ius(
mm
)
Horizontal
W0= 20.91(mm)
Z0=1078.11(mm)Angle= 2.38
0 0.5 1 1.50
50
100
150
200
250
Distance (m)
Bea
m r
adiu
s(m
m)
No plate, y
W0= 6.51(mm)
Z0=-25.86(mm)
Angle= 7.63
0 0.5 1 1.50
50
100
150
200
250
Distance (m)
Bea
m r
adiu
s(m
m)
Vertical
W0= 6.22(mm)Z0= 35.48(mm)Angle= 8.00
Fit
Theory
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Shortcomings of 2-mirror receiver
Studies showed that 2-mirror systems have
• very astigmatic beams ⇒ distortion of off-axis beams
• large degree of focusing ⇒ very sensitive to misalignment
Mirror #2
Horns
Cooling manifold
Mirror #1
Fund. Wave-guides
Blanket Module key
Beam
Mirror #2
Horns
Cooling manifold
Mirror #1
Fund. Wave-guides
Blanket Module key
Beam
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
ITER CTS HFS mock-up Mark III – 4-mirror receiver
• 4-mirrors ⇒ less focusing
• less sensitive to misalignment
• Realistic geometry / Actual antenna mock-up
• Currently being produced in 1:1 scale, i.e. for 60 GHz source
• Goals are to:
• demonstrate an engineering solution to the HFS CTS antenna
• study misalignment
• investigate different horn configurations etc.
• measure the throughput
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
4-mirror HFS CTS receiver integrated into the ITER blanket
Location of the mirrors
Top view of blanket cut-out
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Effects of misalignment – CEM modeling and scattering calc
4 4.5 5 5.5 6 6.5 7 7.5 80
1
2
3
4
5
6ITER CTS
R (m)
L/4
| || |
| || || |
| || || || |
| |
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| |
| |
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| |
| |
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rec : 6rec : 4rec : 2rec : 0rec : -2rec : -4rec : -6
Plasma center +
Vertical receiver misalignment: DS = 1.0
Slit height = 6λ = 30 mm
Aligned beam 4° tilt of beam
Scattering calculations predict:
Vertical misalignment of receiver is less sensitive than for the probe
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Additional measurements – fuel ion ratio
• Similar but separate LFS receiver (same aperture)
• Same probe or separate low power probe – 10 kW
• Temporal resolution of 100 ms
• Limited influence of impurity content
• Could be tested on TEXTOR or ASDEX Upgrade
Zeff 1.82 2.37 4.60
σRi 0.146 0.151 0.138
LFS probe transmission line
LFS receiver transmission line
Horn array
WaveguidesMitre bends
Quasi-opticalmirrors
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Additional measurements – bulk ion drift velocities
• Toroidal bulk ion drift velocity
• readily obtained from the HFS-FS fast ion CTS system
• uncertainty approximately 20 km/s
• Poloidal bulk ion drift velocity
• needs a separate probe and receiver - vertically off-set
• low power probe – 10 kW
• uncertainty approximately 4.5 km/s
• little dependence of impurities
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Future work
• EFDA task TW6-TPDS-DIADEV: Effects of RF- and NBI-generated fast ions on the measurement capability of diagnostics
• Modeling of increased neutron flux
• EFDA task TW6-TPDS-DIASUP: ITER CTS 2007
• Propose a comprehensive outline plan for the full development of the CTS diagnostic for ITER
• engineering designs for both the HFS receiver system and the port-mounted components
• critical issues: • limited space
• nuclear heating
• neutron streaming
• thermal mechanical studies (misalignment)
• waveguides and feed-throughs (collaborate with reflectometry team)
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Summary
• A number of design and test tools have been developed
• a series of mock-ups
• finite difference codes
• 3D astigmatic Gaussian beam codes for mirror shapes
• Key design criteria confirmed
• Blanket cut-out for HFS receiver
• Potential further development of the diagnostic to measure
• fuel ion ratio
• toroidal and poloidal bulk ion drift velocity
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
The resolving power L
• The resolvong power L, is a measure of the information of the fast ion velocity distribution, independent on number of nodes
• Unitless by normalizing with the target accuracy • L2 is approximately the number of nodes resolved with the target
accuracy (provided uncertainties at all nodes are independent)
• 16 nodes ⇒ L > 4 ⇒
60 GHz HFS-FS:
60 GHz LFS-FS:
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Opening angle of HFS receiver beam – calculation
Near field
Gaussian half width – far field
Feasibility study:
2D full wave calculations of the beam pattern through a slit.
Asymptotic opening angle:
To satisfy measuring criteria:
≤ 7° ⇒ h = 30 mm
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Vertical distance between blankets = 14 mm
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.014
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.014
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.014
4 4.5 5 5.5 6 6.5 7 7.5 80
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5ITER CTS
R (m)
L/4
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.014
DS: 0.4DS: 0.7DS: 1.0DS: 1.2
3 4 5 6 7 8 9 10
-5
-4
-3
-2
-1
0
1
2
3
4
5
R / m
z / m
Vertical distance between blankets = 14 mm
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Vertical distance between blankets = 20 mm
3 4 5 6 7 8 9 10
-5
-4
-3
-2
-1
0
1
2
3
4
5
R / m
z / m
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.020
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.020
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.020
4 4.5 5 5.5 6 6.5 7 7.5 80
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5ITER CTS
R (m)
L/4
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.020
DS: 0.4DS: 0.7DS: 1.0DS: 1.2
Vertical distance between blankets = 20 mm
ITPA Diagnostics Meeting, Princeton, March 26 - 30, 2007
Vertical distance between blankets = 30 mm
3 4 5 6 7 8 9 10
-5
-4
-3
-2
-1
0
1
2
3
4
5
R / m
z / m
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.030
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.030
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.030
4 4.5 5 5.5 6 6.5 7 7.5 80
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5ITER CTS
R (m)
L/4
Probe f (GHz): 60
Rec f (GHz): 60
L/4 Tnoise (eV): 200
Probe Y: 0.798
Probe : 195
Probe : 94.79
Probe diam: 0.200, 0.200
rec diam: 0.350, 0.030
DS: 0.4DS: 0.7DS: 1.0DS: 1.2
Vertical distance between blankets = 30 mm