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 APFA Guilin, China November 1-4, 2011 ASIPP 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 2

X-ray Imaging Crystal Spectrometer (XICS) for KSTAR Tangential XICS - Bay F - Installed in Rotation velocity profile measurements Radial XICS - Bay B - Installed in Ti & Te profile measurements Tangential XICS Radial XICS 3

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 4

Layout of X-ray Imaging Crystal Spectrometer Tangential XICS Radial XICS 5

Detectors for XICS on KSTAR tokamak PILATUS Modules - Overall size: 35 mm x 85 mm/module - Pixel size: mm x 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,j N>=3 satellites x y He-like Ar Spectra k q r a Ti and Te inferred from theoretical fits to spectra Rotation velocity from Doppler shift Data Analysis from XICS - Doppler shifts were given relative to the spectral line at certain time, which depends on the Ar gas puffing - 1m Å Doppler shift = km/s for KSTAR - Tiny mechanical vibration caused an extra Doppler shift 7

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 T e from XICS and ECE is almost the same The core V  shows in the counter-current direction B_T = 2.0 T 8 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 rotation increase due to NBI + H-mode 11

H-mode Plasma Parameters for Shot # 5953 V  was increased gradually during the L to H-mode transition H-mode Rotation increase due to H-mode 12

H-mode Core T e, T i, and V  Profiles Center (r = 1.8 m, z = 0 m) : z = 53 cm s : L-mode s : H-mode s : L-mode s : L-mode 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 13

 KSTAR (2011) ▲ KSTAR (2010) J. E. Rice et al., Nuclear Fusion vol (2007) L-H Mode Rotation Changes vs. Stored Energy Normalized by I p 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-D Intrinsic 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 15 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 16

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 reference Natural wavelength marker from Pd filter at = Å (L-III) mode-locking XICS-corrected from LM, ECEI ECEI velocity ~ XICS velocity ECH Shot # 6310 Ar gas injected at 0.5 s NBI injected at 1.0 s XICS reference time Ohmic H-mode 18

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！ 20