1. Spectrometric Diagnosis Group in Plasma Chemistry and Physics 박영동 1, 오수기 2 1 Department of Chemistry, 2 Department of Physics, Ajou University, Suwon 443-749, Korea

2. Vision/Mission High Resolution Spectroscopy/Optical Diagnosis Group Chemistry Laser Spectroscopy Molecular Beam Spectroscopy Photoionization Spectroscopy Physics Interferometry Optics Fabry-Perot Atomic and Plasma Physics

3. Stength/Capacity Chemistry Molecular Spectroscopy Theoretical Spectroscopy Physics Optics – Fourier optics, interferometry Plasma Physics

4. Tokamak Plasma The magnetic field lines inside the tokamak chamber are divided into two groups: the “scrape-off” region cold and diluted the magnetic separatrix surface the “core” region hot and dense One forming nested closed surfaces in the main chamber without touching the material wall the other leading to the divertor chamber

5. The heating effect of the electric current, joule-heating, is less than 50 million degrees. The need for additional heating has led to neutral beam heating. CXS is an appropriate tool to measure the effect of neutral beam heating.

6. The Charge Exchange Recombination Spectroscopy (CXRS) ion temperature poloidal and toroidal rotation speed impurity density Doppler broadening Doppler shift total intensity charge exchange between neutrals in the neutral beams and ions in the plasma H 0 + C 6+ → H + + [C 5+ ] *

7. CXRS system in JT-60U

8. Doppler Broadened Data

9. Mirrors Fabry-Perot interferometer Piezo actuator Photon counter

10. Design of a spectrograph system for temperature measurement in Fusion Reactor using Doppler Broadening Fabry-Perot interferometer system Advantages can achieve very high spectroscopic resolution Disadvantages 1. Need very sharp filter to separate photones outside of free spectral range 2. input beam should be stable during scan period. 3. hard to employ large aperture system

11. McPherson Model 2062 2-meter focal length f/14.1 Monochromator, $200,000 Grating Groove Density (g/mm)1200 Resolution** (nm)0.005 Dispersion (nm/mm)0.4 McPn CXRS 2-meter

12. CCDCCD Light Source Entrance Slit Collimating Mirror Focusing Mirror Grating 2 1800 gr/mm 1st order Grating 1 1200 gr/mm -1st order Grating Groove Density (g/mm)1200+1800 Resolution** (nm)0.007 Dispersion (nm/mm)0.7 AJOU CXRS 50 cm

13. AJOU CXRS

15. FIG. 4. The measured Ne I spectrum lines by the two-grating spectrometer equipped with the PhotonMax 512B CCD camera. AJOU CXRS Ne I =529.8189 nm Ne I =530.4758 nm Ne I =528.0085 nm

16. FIG. 5. The spectrum signals are obtained with the two-grating spectrometer (triangle) and conventional spectrometer (square) for the KSTAR plasma. It is shown that the S/N ratio of the two-grating spectrometer is much larger than that of the conventional spectrometer. McPherson spectrometer(80 ms) Ajou two-grating spectrometer(46 ms) AJOU CXRS McPn CXRS The Ajou system is ~10 times better in S/N for a fraction of the cost for ‘old’ system.

17. FIG. 6.(a) The ion temperature profiles and (b) toroidal rotation velocity measured with both spectrometers for the KSTAR plasma shot number of 4364are compared. AjouMcPherson exposure(m s) 4680 intervals(ms)50100

18. The Charge Exchange Recombination Spectroscopy (CXRS) system in an upper port plug for ITER. Figure from http://www.rijnhuizen.nl/annual_report/2007/02_the_research_at_rijnhuizen/2_2.html diagnostic neutral beam the viewing lines optical fiber bundle spectrometers ITER CXRS

19. Number of channelstoroidal : 23poloidal : 36 Spatial resolutiontoroidal : 5 cmpoloidal : 0.8/1.5 cm Time resolution16.7 ms JT-60U What’s Next? K-STAR target Number of channelsThe more, the better 128 channels Time resolution16.7 ms 20 ms 1.Increase S/N by a factor of 3 or greater. 2.Needs a CCD detector at Ajou. 3.Design multilayer spectrometer systems. 4.A few researchers.(Grads, Post doc.)

20. 올해도 복스러운 해가 되기를 기원합니다

21. [Spectroscopic principle for CXRS] Neutral atom (H 0 ) and impurity ion (A q+ ) undergo a charge transfer that leaves the product ion in an excited state. H 0 + A q+ → H + + [A (q-1)+ ] * A q+ = C 6+. carbon is one of intrinsic impurities and they are fully stripped throughout the plasma volume. Emissions are excited at wavelengths long enough for making accurate Doppler broadening and shift measurements. [Diagnostic Method] One of heating beams NB #14 is used for this measurement (see figures). Due to the above reaction, carbon ions near the neutral beam emit green light (529.2 nm at n=8-7 transition). Doppler broadening (→ temperature), Doppler shift (→ rotation velocity) and its area (→ impurity density). According to the ionization balance, there are C 5+ ions in the edge region, which can emit at the same transition due to direct excitation by electrons (not by neutral beams). Therefore it is important to separate the spectrum by beam excitation from that by electron excitation. In order for this, CXRS system in JT-60U has an exclusive optics for the background spectrum. From Y. Koide, A. Sakasai, Y. Sakamoto, H. Kubo and T. Sugie, Rev. Sci. Instrum. 72, 119 (2001)