Measurement of toroidal rotation velocity profiles in KSTAR
S. G. Lee, Y. J. Shi, J. W. Yoo, J. Seol, J. G. Bak, Y. U. Nam, Y. S. Kim, M. Bitter, K. Hill and the KSTAR Team
2011 APFAGuilin, China
November 1-4, 2011
ASIPPASIPP 1/20
Outline
• Experimental layout- X-ray imaging crystal spectrometer (XICS) for KSTAR- Detector systems for XICS
• Data analysis
• Experimental results- L-mode plasma rotation studies- H-mode plasma rotation studies- ECH effects on rotation in the H-mode plasma
• Summary and future works
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X-ray Imaging Crystal Spectrometer (XICS) for KSTAR
Tangential XICS - Bay F - Installed in 2010 - Rotation velocity profile measurements
Radial XICS - Bay B - Installed in 2009 - Ti & Te profile measurements
Tangential XICS
Radial XICS3
Field of View for XICS
Radial XICS
Tangential XICS
Measurement limit : - 35 cm < z < 35 cm at R = 180 cm
Measurement limit : - 47 cm < z < 47 cm at R = 180 cm
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Layout of X-ray Imaging Crystal Spectrometer
Tangential XICS
Radial XICS
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Detectors for XICS on KSTAR tokamak
PILATUS Modules- Overall size: 35 mm x 85 mm/module- Pixel size: 0.172 mm x 0.172 mm- Maximum count rate: 1 MHz per pixel- Time resolution: > 10 ms
Tangential XICSRadial XICS
Multi-Wire Proportional Counter- Overall size: 100 mm x 300 mm- 4 segmented detector modules- Maximum count rate: 0.8 MHz/module- Time resolution: > 100 ms 6
W
Z,jN
>=
3 sa
tell
ites
x y
He-like Ar Spectra
kq r a
Ti and Te inferred from theoretical fits to spectra
Rotation velocity from Doppler shift
Data Analysis from XICS
- Doppler shifts were given relativeto the spectral line at certain time,which depends on the Ar gas puffing
- 1m Å Doppler shift = 13.33 km/sfor KSTAR
- Tiny mechanical vibration caused an extra Doppler shift
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Ohmic Plasma for Shot # 5648
V from ECEI measurement assumed that the observed m/n =1/1 mode is the internal kink, which is not moving in the plasma frame, thus, the internal kink can provide the core plasma toroidal rotation velocity in the lab frame.
V from XICS is calibrated with V from ECEI at t = 2.52s
=> Main plasma ion and argon impurity core toroidal rotation velocities are the same
The core Te from XICS and ECE is almost the same
The core V shows in the counter-current direction
B_T = 2.0 T
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ECEI data provided from Dr. G. S. Yun
L-mode Toroidal Rotation During MHD Activity
The core V increased in the counter-current direction during MHD activity 9
Toroidal MC array
Poloidal MC array
Mirnov Coil Data Analysis During MHD Activity
f ~ 1 kHz, n =1 & m = 2
The measured core V corresponds to the rotation frequency of f ~ 1 kHz (at major radius R = 1.8 m) : V = 2 R f ~ 11.3 km/s 10
H-mode Plasma Parameters for Shot # 5505
Large V increasing showed during the L to H-mode transition coincidence with NBI
H-mode
Large rotationincrease due to NBI + H-mode
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H-mode Plasma Parameters for Shot # 5953
V was increased gradually during the L to H-mode transition
H-mode
Rotation increasedue to H-mode
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H-mode Core Te, Ti, and V Profiles
Center (r = 1.8 m, z = 0 m) : z = 53 cm
1.9091 s : L-mode 2.8227 s : H-mode 3.7254 s : L-mode 4.6221 s : L-mode 5.5348 s : L-mode
Flat rotation profile
1.26 s : L-mode 2.30 s : H-mode 3.37 s : H-mode 4.44 s : H-mode 5.51 s : L-mode
Shot # 5505
Shot # 5953
Peaked rotation profile
Center (z = 0 m, R = 1.8 m) position : z = 53 cm
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KSTAR (2011) ▲ KSTAR (2010)
J. E. Rice et al., Nuclear Fusion vol.47 1618 (2007)
L-H Mode Rotation Changes vs. Stored Energy Normalized by Ip
For KSTAR
• Rotation velocity was measured in the core region• Plasma current is 0.6 – 0.7 MA
V : Intrinsic rotation due to H-mode W : Plasma stored energy change I : Plasma current
The slope of a line through the data points showed a little change except DIII-DIntrinsic rotation scaling related with machine size/geometry and heating sources 14
V was not increased dramatically during the L to H-mode transition due to the ECH, which induced a counter-rotation torque
110 GHz 170 GHz
H-mode
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ECH Effect on Toroidal Rotation in H-mode Plasma
ECH Effect on Toroidal Rotation in H-mode Plasma
On-axis ECH
Shot # 5737
Time (sec)
• V was decreased during on-axis ECH in the H-mode plasma• A broad rotation profile in the core was measured during ECH• ITG ↔ TEM transition maybe the mechanism for the counter-rotation torque from the ECH
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ECH Resonance Layer Scan in H-mode plasma
Off-axis ECH makes smaller counter-rotation torque compared to that of the on-axis 17
In situ/absolute calibrations for XICS
Locked-modes :- RMP - Mode-locking should be stagnant
ECEI : Plasma rotation velocity from ECEI can be used for XICS referenceNatural wavelength marker from Pd filter at = 3.9071Å(L-III)
mode-locking
XICS-correctedfrom LM, ECEI
ECEI velocity ~ XICS velocity
ECHShot # 6310Ar gas injected at 0.5 sNBI injected at 1.0 s
XICSreferencetime
Ohmic H-mode
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Summary and Future Works
The measured argon impurity toroidal rotation velocity is almost the same as that of the primary deuterium ion, which was experimentally proven.
The toroidal rotation velocity was increased in the counter-current direction with occurrence of certain MHD activity.
Toroidal rotation velocity profile from XICS is applying for many important physics studies, which is under progress:
- Ohmic plasma rotation studies- ECH rotation studies in L and H-mode plasmas- L to H-mode transition and back transition- Intrinsic rotation studies- MHD activity- RMP- SMBI
In situ and/or absolute calibrations for the absolute toroidal rotation velocity will be performed from 2012 experimental campaign. 19
谢谢!
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