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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