1. 1 CENTER for EDGE PLASMA SCIENCES C E PS Status of Divertor Plasma Simulator – II (DiPS-II) 2 nd PMIF Workshop Sep. 19, 2011 Julich, Germany H.-J. Woo 1, K.-S. Chung 1, S.-J. Park 1, S.-G. Cho 1, E.-K. Park 1, and T. Lho 2 1 Center for Edge Plasma Science, Hanyang University, Seoul 133-791, Korea 2 National Fusion Research Institute, Daejeon 305-333, Korea

2. 2 CENTER for EDGE PLASMA SCIENCES C E PS CONTENTS Review of DiPS – I LaB 6 Cathode Concepts and Objects of DiPS – II Summary and Future Work

3. 3 CENTER for EDGE PLASMA SCIENCES C E PS  DiPS-I : Schematics LaB 6 is located at null magnetic field. DiPS - I

4. 4 CENTER for EDGE PLASMA SCIENCES C E PS  Typical Magnetic Field of DiPS-I DiPS - I

5. 5 CENTER for EDGE PLASMA SCIENCES C E PS 5 Probe Diagnostics : I-V Characteristics vs. Magnetic Field vs. Discharge Current Dimensions of Probe Tip: 0.5 mm (Dia.) and 3 mm (length) DiPS – I : Experimental Results

6. 6 CENTER for EDGE PLASMA SCIENCES C E PS 6 Probe Diagnostics : Electron Temperature (T e ) and Plasma Density (n p ) vs. Magnetic Field vs. Discharge Current Plasma Density : Confinement Effect Plasma Density : Particle Flux Density DiPS – I : Experimental Results

7. 7 CENTER for EDGE PLASMA SCIENCES C E PS 7 LIF Diagnostics vs. Magnetic Field Ion TemperatureDrift Velocity Ion temperature and parallel flow velocity are increased versus the magnetic field intensity. The perpendicular flow velocity remains near zero, since the contributions of E X B and diamagnetic effect are negligible at the plasma center in the magnetized cylindrical plasmas. DiPS – I : Experimental Results

8. 8 CENTER for EDGE PLASMA SCIENCES C E PS 8 LIF Diagnostics vs. Discharge Current Ion TemperatureDrift Velocity Ion temperature and parallel flow velocity are increased versus the discharge current. DiPS – I : Experimental Results

9. 9 CENTER for EDGE PLASMA SCIENCES C E PS 9 Ion Temperature and Drift Velocity vs. Plasma Density Magnetic Field Variation → Ion Temperature (Plasma Density + Magnetic Field) Discharge Current Variation → Ion Temperature (Plasma Density) DiPS – I : Experimental Results

10. 10 CENTER for EDGE PLASMA SCIENCES C E PS  LaB 6 Cathode for DiPS – I & II LaB 6 Cathode for DiPS – I & II

11. 11 CENTER for EDGE PLASMA SCIENCES C E PS  LaB 6 Cathode for MP 2 – Large Plasma Source LaB 6 Cathode for Large Plasma Generation

12. 12 CENTER for EDGE PLASMA SCIENCES C E PS  Heater Temperature Estimation LaB 6 Cathode : Heater Temperature Estimation

13. 13 CENTER for EDGE PLASMA SCIENCES C E PS B. Noyes, Jr., Phys. Rev. 24, 190 (1924).  Heater Temperature Estimation LaB 6 Cathode : Heater Temperature Estimation

14. 14 CENTER for EDGE PLASMA SCIENCES C E PS  Objective of DiPS-II Understanding of the Plasma Wall Interaction Higher Plasma Flow Generation with Magnetic Nozzle Concept. Characterizations of Attached/Detached Plasmas (Neutral Effects). – Need Highly Differential Pumping Developments of Diagnostics for KSTAR. Tests of PFC Materials. DiPS - II DiPS – II has been developed to overcome the weaknesses of DiPS – I and improve the machine performance. Weaknesses of DiPS – I: Neutral Pressure Control – only two section separated by differential pumping. Low Particle Flux – limited plasma current. Small Plasma Size : Core Plasma Size ~ 2 cm

15. 15 CENTER for EDGE PLASMA SCIENCES C E PS DiPS - II B. Labambard, 21 st Transport Taskforce Workshop, Boulder, CO (March 25-28, 2008).

16. 16 CENTER for EDGE PLASMA SCIENCES C E PS  Concepts of Magnetic Nozzle – From Helicon Experiments X. Sun, Phys. Rev. Lett. 95, 025004 (2005) HELIX and LEIA, West Virginia University Helicon Plasma Without Ion Heating VASIMR Concepts DiPS - II

17. 17 CENTER for EDGE PLASMA SCIENCES C E PS Measurement Position A & B  Concepts of Magnetic Nozzle – From Experience of MP 2 (NFRI: Dr. LHO) DiPS - II

18. 18 CENTER for EDGE PLASMA SCIENCES C E PS 18 High Field Chamber (Position A) : Magnetized 1 st Port of Central Cell (Position B) : Un-magnetized  Concepts of Magnetic Nozzle – From Experience of MP 2 (NFRI: Dr. LHO) DiPS - II

19. 19 CENTER for EDGE PLASMA SCIENCES C E PS 19  Concepts of Magnetic Nozzle – From Experience of MP 2 (NFRI: Dr. LHO) High Field Chamber (Position A) : Magnetized 1 st Port of Central Cell (Position B) : Un-magnetized DiPS - II

20. 20 CENTER for EDGE PLASMA SCIENCES C E PS  Schematic Diagram of DiPS-II Magnetic Nozzle DiPS - II

21. 21 CENTER for EDGE PLASMA SCIENCES C E PS  Typical Magnetic Field of DiPS-II Magnet Power SupplyMagnet LabelDefault Current Sorensen SGI 80- 125M1 – M280 A (Max. 125 A) Sorensen SGI 80 - 125M3 – M460 A (Max. 125 A) Sorensen SGI 40 – 250 (Parallel)M5 – M6450 A (Max. 500 A) Sorensen SGI 200 – 125M7 – M125 – 90 A (Max. 125 A) DiPS - II

22. 22 CENTER for EDGE PLASMA SCIENCES C E PS Diagnostics and Material Test Regime First Plasma at Sep. 2010. DiPS - II  Construction and Plasma Generation

23. 23 CENTER for EDGE PLASMA SCIENCES C E PS  LaB 6 Cathode Damage (Melting) at High Current Operation (over 90 A) In diverging field configuration, the LaB6 cathode can be damaged by localized current in light gas operation such as helium (low ion gyro-radius). → Need the Null Field Geometry LaB 6 Cathode Melting DiPS - II

24. 24 CENTER for EDGE PLASMA SCIENCES C E PS DiPS – II : Flow Measurement Results The plasma flow velocity is nearly zero (stationary plasma), which might be due to grounded chamber wall disturbs the ion acceleration.

25. 25 CENTER for EDGE PLASMA SCIENCES C E PS  Install Laser Thomson Scattering for Detached Plasmas & Material Test Mirror & Lens Array TS Sample Horizontal Pixel No. (related to Wavelength) Vertical Pixel No. (related to Radial Position) R = 0 mm R = - 3.5 mm R = +3.5 mm R = -7 mm R = +7 mm R = +10.5 mm R = +14 mm R = -14 mm R = -10.5 mm Blocked Region (Rayleigh Scattering) DiPS – II: TS Diagnostics

26. 26 CENTER for EDGE PLASMA SCIENCES C E PS DiPS – II: TS Diagnostics 40 A Discharge with Ar

27. 27 CENTER for EDGE PLASMA SCIENCES C E PS Typical Divertor DiPS-1DiPS-2 Pressure @ Source (mTorr)1 – 30200 - 40020 - 50 Pressure @ Transient (mTorr)-5 Pressure @ Diagnostics (mTorr) 1 - 301 - 100.1 – 100 Core Plasma Size~2 cm~ 5 cm Plasma Density (cm -3 )10 13 – 10 14 <10 14 @ near Source ~10 12 @ diagnostics ~10 13 @ Diagnostics Electron Temperature (eV)1-10 eV 2-3 eV for Ar, 5-7 eV for He 2-3 eV for Ar, 5-7 eV for He Ion TemperatureT i ~T e 0.1 eV for Ar Particle Flux (m -2 s -1 )~ 10 24 ~10 22 10 22 - 10 24 Magnetic Field~ 3 T~ 1 kG B T =3.5 kG, B D =1.5 kG max. Discharge Voltage ~ 30 - 40 V for Ar ~ 60 - 80 V for He ~ 50-70 V for Ar ~100 V for He Discharge Current50 A DC150 A DC SUMMARY

28. 28 CENTER for EDGE PLASMA SCIENCES C E PS SUMMARY DiPS-1DiPS-2 PLASMA DIAGNOSTICS PROBES LASER-INDUCED FLUORESCENCE LASER THOMSON SCATTERING ETC Small Size Ion Beam Source will be Installed for Material Damage Test

29. 29 CENTER for EDGE PLASMA SCIENCES C E PS One will change magnetic nozzle chamber as floating structure (or biased structure), which is now grounding. One also add the source magnet for cusp magnetic field. The design is already finished. FUTURE WORK