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International Collaboration On Lower Hybrid Current Drive Alain Bécoulet, Tuong Hoang,

International Collaboration On Lower Hybrid Current Drive Alain Bécoulet, Tuong Hoang,.

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International Collaboration On Lower Hybrid Current Drive Alain Bécoulet, Tuong Hoang,

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  1. International Collaboration On Lower Hybrid Current Drive Alain Bécoulet, Tuong Hoang, J.F. Artaud, Y.S. Bae, J. Belo, G. Berger-By, J.M. Bernard, Ph. Cara, A. Cardinali, C. Castaldo3, S. Ceccuzzi, R. Cesario, M. H. Cho, J. Decker, L. Delpech, H. J. Do, A. Ekedahl, J.Garcia, P. Garibaldi, M. Goniche, D. Guilhem, C. Hamlyn-Harris, J. Hillairet, Q.Y. Huang, F. Imbeaux, H. Jia, F. Kazarian, S.H. Kim, Y. Lausenaz, X. Litaudon, R. Maggiora, R. Magne, L. Marfisi, S. Meschino, D. Milanesio, F. Mirizzi, P. Mollard, W. Namkung, L. Pajewski, L. Panaccione, S. Park, H. Park, Y. Peysson, A. Saille, F. Samaille, G. Schettini, M. Schneider, P.K. Sharma, A. Tuccillo, O. Tudisco, G. Vecchi, R. Villari, K. Vulliez, Y. Wu, H.L. Yang, Q. Zeng

  2. LHCD to sustain steady-state long pulses its possible mission in ITER H&CD mix Conceptual design of the ITER LHCD system: physics, technology Recent advances of Lower Hybrid Current Drive Technology R&D requirements for ITER Conclusions OUTLINE

  3. Present Super Cond. devices Steady State or Long Pulse Operation? • “Steady-state”deals with physics timescales (MHD, energy confinement, current diffusion) • “Long Pulse Operation” refers to the integration of physics and technology

  4. Long Pulse Operation simultaneouslyrequires • the long term operation of the magnetic configuration (current profile) • the long term operation of the kinetic configuration (temperature, confinement, particle content, rotation profiles) • the long term safe operation of the Coils, Plasma Facing Components, Structure Materials,H&CD systems, Diagnostics, … • a long term solution for fuel cycle (T)

  5. HT-7 400s discharge [B. Wan 2009] Tore Supra6-min. discharge [Van Houtte 05] EAST one-minute discharge [B. Wan 09] All Tokamak Long Pulses are sustained by LHCD • Hours in TRIAM-1M • Minutes in EAST, HT-7 and Tore Supra (level of MA-MW)

  6. Which Mission(s) for LHCD in ITER ? • Extend burn duration -> save Volt-seconds, from early plasma phases • Help Accessing and Sustaining Steady-State (Advanced Tokamak Physics) -> Drive far off-axis current, complementarily to Bootstrap Current, NBCD and ECCD.

  7. (d) (c) (b) (a) LHCD Extending Burn Duration • Early application of LHCD (20MW) in the current ramp-up saves ~ 45Wb -> ~ 500s of burn duration [Kessel, Nucl. Fus. 2009; Kim, PPCF, 2009] • Decrease of plasma inductance li: li ≤ 0.3, beneficial for plasma vertical control [Hoang, Nucl. Fus. 2009] • All PF coil currents well within limits

  8. up to45Wb (heating), preserved to the end of burn li decreases (off-axis LH current), li ≤ 0.3 All PF coil currents well within their limits Physics Design: Vs Saving

  9. Propagation Pedestal LHCD Driving Off-Axis Current in ITER • Optimized N// index range: 1.8 – 2.2, OK for all scenarios • Current deposition range: 0.6<r/a<0.8 • Driven Current ~ 1MA (20 MW coupled / 14 MW in main wave lobe)

  10. ILH RAY-STAR (Cardinali) C3PO/LUKE Simulated LHCD in ITER SS scenario (#4) • C3PO/LUKE/ALOHA: 14 MW of absorbed power (20MW injected) drive < 0.7MA disagrees with RAY-STAR (> 0.9MA) -> runs from other codes under same conditions

  11. EC+IC+LH 21+20+13 MW RF-only H&CD Steady-state operation Steady-state Q ~7 / 3000scould be achieved • ECCD triggers and locks ITB position @ r/a ~ 0.5 • LHCD drives current @ 0.6-0.8 required for SS [Garcia PRL 08. This conference]

  12. LHCD to sustain steady-state long pulses. Its possible mission in ITER Conceptual design of the ITER LHCD system: physics, technology Recent advances of Lower Hybrid Current Drive Technology R&D requirements for ITER Conclusions OUTLINE

  13. A LHCD system for ITER • ITER Design Review and ITER STAC -> 20 MW LHCD system for ITER under consideration; for future Upgrade. • Five ITER partners joined efforts on conceptual design and feasibility study (voluntary basis): CN, EU (under EFDA), IN, KO, and US. • Feasibility Study initiated and coordinated by CEA/IRFM, under EFDA (“LH4IT” task) • Five Euratom-Associations (incl. 7 laboratories) involved in training young RF scientists/engineers on all aspects(“LITE” training programme)

  14. The ‘LH4IT’ task Deliverable: pre-design document including conceptual design, costing, schedule, WBS, and R&D needs • CEA (coord.), ENEA, IST, POLITO, Univ. ROME 3, (CCFE, IPP-Prague, follow-up only) • Contribution from IO (HCD Department) • Support of International LHCD community: China, India, Korea, and US. Japan following-up.

  15. Status Report • Physics Design updated (absorption, propagation, alpha particle issue,…), incl. contribution to scenario development • ITER System Requirement Document delivered, and Work Breakdown Structure • Integration on ITER, incl. RAMI aspects • DDD2001 conceptual design revised (antenna, T-Lines, control & protection system + assoc. diagnostics, power supply)

  16. Findings • A 20 MW CW LHCD system in ITER is technically feasible, based upon: • - one Passive Active Multijunction (PAM) launcher • N// = 2 (or 1.9)  0.2 • 48 klystrons 500 kW/CW at 5 GHz • (3.7 GHz fall back solution) • 48 main transmission lines (could be halved) • 12 HVPS units (likely 90kV/90A) • Costing: ~ 80M€ (~ 4€/W) • Schedule: 9-10 years, including detailed design and R&D

  17. Passive Active Multijunction Launcher Concept 1152 active waveguides (WG): 48 modules of 6 (poloidal direction) x 4 (toroidal direction) active WGs; One module: 6 rows of multi-junction (24 active WGs), 2 mode converters, 2 tapers, 1 splitter, 1 transmission line, 1 bellow, 1 window [Hillairet, this Conference]

  18. Modification of DDD2001 PAM proposed • 4 active WG modules to improve the flexibility: N// = ± 0.2(initial design: 8-WG module, N// = 2 ± 0.1) • Directivity ~ 70% @ the cut-off density • Optimizing bi-junctions to reduce RC <1.5%, in a wide range of density up to 12 x cut-off density Reflect. coeff. (%) Hillairet, this Conference Milanesio, this Conference

  19. DDD2001 Case B Case A Antenna Front Face • Different models have been analyzed: • DDD2001 PAM model • 2 Alternative PAM models “Case A” and “Case B” • Acceptable Surface Temperature;<650°C for all designs • Better knowledge of the Be-Cu joint (HIP) needed -> R&D required Marfisi, this Conference

  20. B: Transmission lines C: Launcher A: Klystrons ITER LHCD layout • Foreseen distance between the klystrons and the launcher could be reduced at about 50m • 48 rectangular transmision lines maximum (or 24 circular) [Mirizzi this Conference]

  21. LHCD to sustain steady-state long pulses. Its possible mission in ITER Conceptual design of the ITER LHCD system: physics, technology Recent advances of Lower Hybrid Current Drive Technology R&D requirements for ITER Conclusions OUTLINE

  22. High power CW Klystron Development • Toshiba: CW / 5 GHz prototype for KSTAR • Communications and Power Industries, Inc : production in series of CW / 4.6 GHz tubes for EAST (used in C-Mod) • Thalès Electron Devices: production in series(18) CW / 3.7GHz for Tore Supra [Park, Fus. Eng. and Design (2010); Lenci, Vacc. Electronics Conf. IVEC 2009, IEEE International; Kazarian, Fus. Eng. and Design (2009)]

  23. CW high-power tests of the 500kW /5GHz klystron restarted In Feb 2010 at NFRI, with new capability of the test stand. Participation of CEA. 460 kW/20s; ~300kW / CW @ VSWR=1.12 2009 2010

  24. 5GHz / CW Klystron Prototype Commissioned at NFRI • So far 300 kW /800s(VSWR = 1.12, efficiency 43%), 460kW/20s (factory test: 300kW/12min; 500kW/0.5s,) Oscilloscope screen shot of the cathode (beam) and the anode voltages and current for 304 kW / 800s pulse [Do, this Conference]

  25. TED 3.7GHz / CW Klystrons for Tore Supra 700 kW / 1000s • 18 klystrons delivered and being commissioned separately • 620kW/CW @ VSWR =1.4routinely, and 720kW/CW @ VSWR=1 • Efficiency of 47% Kazarian et al., FED (2009); Delpech et al., 18th RF Top Conf. (2009)

  26. 700kW / CW SPINNER Water Load Validated Delpech this Conference

  27. Manufacturing Tore Supra 3.7GHz PAM launcher Concept. Ph. Bibet Scales as ¼ of the ITER launcher size (7 tons!) Mode Converters (rear view) Passive Active Multijunction (front view) Guilhem, this Conference

  28. Installing Tore Supra PAM launcher

  29. An extremely fast commissioning period 2009: 4 days with vacuum conditioning 12 sessions with plasma • 1st discharge with all klystrons: 450kW / 4.5s, N// ok, low reflected power (~1.5%) • 240th plasma pulse: 2.7MW / 17s 2010: • 2.75 MW / 78s (220MJ) • Full current drive during 50s at 2.2MW Participation of 15 collaborators from 7 countries IST, Lisbon; IPP-CR Prague; CCFE, Culham; ENEA-Frascati; IPR, India; SWIP, China; NFRI, South Korea; Ekedahl, to appear in Nucl. Fus. Oct 10

  30. ELHCD = 220MJ ITER-relevant power density for 78s • 2.75MW (25MW/m2) coupled with PAM for 78 seconds • Low reflect. coefficient < 2% at large plasma-launcher gap (density above cut-off) • Efficient cooling: Waveguides/side protections temp. < 300C Infrared monitoring

  31. LHCD Power coupled in ELM-like edge plasmas • Reflection coefficient behaves according to modeling. • Intermediate power (1.5MW) sustained during Supersonic Molecular Beam Injection (SMBI). • No change in Hard X-ray emission profile SMBI is used to mimic ELMs Sharma 37th EPS Conf.

  32. Full Current Drive for 50s • CD efficiency: LHCD ~ 0.8x1019A/W/m2; similar to full active multijunction launchers

  33. LHCD to sustain steady-state long pulses its possible mission in ITER Conceptual design of the ITER LHCD system: physics, technology Recent advances of Lower Hybrid Current Drive Technology R&D requirements for ITER Conclusions OUTLINE

  34. Specific R&D activity • Transmission lines, RF windows, mode filters; must be adapted to ITER constraints • Minimize the number of transmission lines. • 500kW/CW RF windows exposed to the ITER environment must be developed and tested. • PAM plasma facing front • The 500kW/5GHz Toshiba prototype klystron has to be validated @ 500kW/CW under VSWR > 1.4. • Need R&D program, conducted jointly by fusion community and industrial partners, to avoid the risk of failure of fabrication and the excessive cost as well.

  35. Schedule: 9-10 years required

  36. CONCLUSIONS • LHCD is a mature method used in a large number of tokamaks • In ITER, LHCD is seen to be a unique CD tool for driving far off-axis current (r/a > 0.6) • An ITER LH voluntary program is underway • A 20 MW / 5 GHz / CW LHCD system using one Passive Active Multijunction (PAM) launcher in ITER is technically feasible • ~ 9 years are necessary between the decision point by stakeholders and the start of the commissioning phase on ITER,if the required R&D is timely initiated and if the competence of Fusion laboratories and industries is maintained

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