Toroidal Rotation and Ion Temperature Validations in KSTAR Plasmas

Transcription

1 Toroidal Rotation and Ion Temperature Validations in KSTAR Plasmas S. G. Lee 1, H. H. Lee 1, W. H. Ko 1, J. W. Yoo 2, on behalf of the KSTAR team and collaborators 1 NFRI, Daejeon, Korea 2 UST, Daejeon, Korea 1 st IAEA Technical Meeting on Fusion Data Processing, Validation and Analysis June 1-3, 2015 Nice, France

2 Outline Introduction Main diagnostics for toroidal rotation and ion temperature measurements in KSTAR Experimental results Summary 2

3 X-ray Imaging Crystal Introduction Spectrometer (XICS) Two main diagnostics for toroidal rotation and ion temperature measurements have been installed on KSTAR - X-ray imaging crystal spectrometer (XICS) - Charge exchange spectroscopy (CES) Cross comparisons of the toroidal rotation and ion temperature from the XICS and CES were selected as the ITPA/IEA JEX DIAG-6 in 2014 The toroidal rotation and ion temperature of different impurity species from the XICS and CES have been simultaneously compared with various plasmas in KSTAR A two Gaussian fitting from CES measurements without beam modulation is needed for long-pulse advanced operating scenarios 3

4 X-ray Imaging Machine Crystal Status Spectrometer of KSTAR (XICS) 4

5 Two Main Diagnostics on KSTAR B A P O Co-rotation (+) Counter-rotation (-) N C V M NBI CES D L E K F XICS G H I J 5

6 Concept of X-ray Imaging Crystal Spectrometer (XICS) Spherical Crystal Rowland Circle Detector Location Due to the astigmatism a point source on the Rowland circle has two images at f m and f s, formed by the meridional and sagittal rays. For a Bragg angle of 45, F s is at infinity, so that - if the rays are reversed - a parallel bundle of X-rays from the plasma is focused to a point on the detector. The imaging is rotationally symmetric about the normal of the crystal. 6

7 N>=3 satellites X-ray XICS Imaging on KSTAR S) W He-like Ar Spectra x y q r a k Z,j V = (c/sin ) ( / ) T i, T e and toroidal rotation velocity profiles in the core region with 2 ms Need Ar gas puffing, rotation calibration Toroidal rotation (V ) inferred from Doppler shift ( ) 7

8 Toroidal Rotation Calibration for XICS Calibration for XICS is performed for every discharge in KSTAR Locked-modes : - RMP - Mode-locking should be stagnant MHD/ECEI : Sawtooth pre-cursors CES : Cross-calibration Shot # 6310 Ar gas injected at 0.5 s NBI injected at 1.0 s mode-locking XICS reference time Corrected XICS 8

9 Concept of Charge Exchange Spectroscopy (CES) Line of sight from the optics always intersects neutral beam line and plasma edge region From the plasma edge region (passive CX emission) 1. spectral lines coming from the charge exchange between thermal neutrals and carbon particles 2. spectral lines produced by electron excitation Since only the active component is of interest, the undesirable background component (passive CX emission) should be decomposed from the measured spectrum in order to estimate the temperature, rotation velocity and impurity density. Beam modulation technic is applied for KSTAR 9

10 CES on KSTAR Ion temperature (Ti) and rotation velocity ( ) profiles from core to edge Feasibility test of poloidal CES was successfully performed in 2014 V Name Time resolution Spatial resolution Ti, V (Vq)range System location No. of Channels NBI modulation Impurity Spectrometer Interval System Requirements (2014 Target) 10 ms (100 Hz) 2~10 cm (Core), 5~10 mm (Edge) > 100 ev, > 4 km/s (> 1 km/s) Core/Edge port - M M (toroidal), K M (poloidal) 32 pts + 16 pts (Max. 48 pts available) 2 ~ 5 Hz (requirement) CVI( nm) DS-spectrometer(DU897) & K-spectrometer 5 cm (Core), 5 mm(edge) for toroidal (>32 pts) 10 cm (Core), 10 mm(edge) for poloidal (>16 pts) CES NBI Need NBI with beam modulation 10

11 Core Toroidal Rotation and Ion Temperature Verifications ELMy H-mode Data from XICS and CES can be compared during beam modulation 11

12 Core Toroidal Rotation and Ion Temperature Verifications ELM-free H-mode Data from XICS and CES can be compared during beam modulation 12

13 Core Toroidal Rotation and Ion Temperature Verifications L-mode H-mode Data from XICS and CES can be compared during beam modulation 13

14 Toroidal Rotation Profiles from XICS and CES XICS Toroidal rotation is significantly reduced during on-axis ECH injection Mechanism : NTV torque caused by the internal kink mode is counter directed to the toroidal rotation direction CES 14

15 Two Gaussian Fitting for CES without Beam Modulation Two-Gaussian fitting needs to find the most suited two Gaussian curves from a non-linear least square method 15

16 Core Toroidal Rotation and Ion Temperature Verifications Two Gaussian fitting for CES without beam modulation 16

17 Beam Blip Needs Careful Analysis in Ohmic Plasmas I p (MA) n e (10 19 m -3 ) V (km/s) XICS CES 9312 NBI blips Time (sec) Beam blip for CES rotation measurements are widely used - Main plasma parameters should not be perturbed - XICS noticed the beam torque even though a short beam blip 17

18 Toroidal Rotation Verification in Ohmic Plasma The core Te from XICS and ECE is almost the same The core V shows in the counter-current direction Ar gas puffing V from XICS is corrected with V from ECEI at t = 2.52s 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 18

19 Summary Cross comparisons of the toroidal rotation and ion temperature from the XICS and CES are possible since KSTAR equips two main diagnostics. Simultaneous measurements for the toroidal rotation and ion temperature with various plasma conditions of different impurity species from the XICS and CES have shown reasonable agreements. Two Gaussian fitting for the toroidal rotation measurement from the CES showed a good possibility for the future reference without beam modulation environments. The toroidal rotation and ion temperature measurements from the XICS confirmed during long-pulse H-mode and it can be extended continuously. 19

20 Thank you!