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ITER Energetic Particle Physics R&D Needs

Energetic Ion Physics Specify effects of magnetic field ripples on energetic ion losses and wall heat load in ITER Specify effects of collective instabilities on energetic ion losses and wall heat load in ITER Specify interaction of energetic ions with background MHD in ITER

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ITER Energetic Particle Physics R&D Needs

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  1. Energetic Ion Physics Specify effects of magnetic field ripples on energetic ion losses and wall heat load in ITER Specify effects of collective instabilities on energetic ion losses and wall heat load in ITER Specify interaction of energetic ions with background MHD in ITER Runaway Electron Physics Develop physics basis for mitigation of disruption- generated runaway electrons in ITER ITER Energetic Particle Physics R&D Needs Mukhovatov, October 2008

  2. Heat loads to the walls due to fast ion losses Acceptable loads (ITER Technical Basis): Divertor: <10 MW/m2 Limiter (average/max.): 3 MW/m2 / 8 MW/m2 Wall: 0.25 MW/m2 / 0.5 MW/m2 (Neutron wall loading: 0.56 MW/m2 / 0.78 MW/m2)

  3. Effect of TF ripple on energetic ion losses Agreement between the codes: Present design of FI significantly reduce fast ion losses full field Shinohara, October 2008

  4. Agreement between the codes: Present design of FI significantly reduce fast ion losses with FI, full field no FI, full field Total wall load: 310 kW Peak heat flux: 200 kW/m2 Limiter/divertor/wall: 60%/38%/2% Total wall load: 1040 kW Peak heat flux: 500 kW/m2 Limiter/divertor/wall: 72%/11%/17% Kurki-Suonio, October 2008

  5. Non-periodic (TBM induced losses) of energetic ions Shinohara, October 2008

  6. A lot of discussions at IAEA conference and ITER STAC for TBM induced losses But: Except for F3D-OFMC results, input for vacuum fields not correct (no effect of plasma currents) Magnetic islands? Might be an artificial effect as induced by the wrong field geometry (pitch angle!) Kurki-Suonio, October 2008

  7. Except for Japanese results, input for vacuum fields not correct (no effect of plasma currents) Big n=1 (resonant) perturbation in the plasma Plasma response onto 3d vacuum fields? Spong, October 2008

  8. One worry has been sorted out since fall meeting: • Ergodized particle orbits had been predicted when following the full orbits with field ripple • -> large heat leads to the wall expected • (Kramer et al. IAEA, ITPA) • BUT: • results were not correct • Guiding centre orbit calculations are sufficient, also for ITER scenario 4

  9. Working plan for ripple induced fast ion losses • Short term actions (2009) • Code benchmarks: F3D OFMC (Japan), ASCOT (Finland), ORBIT (US), SPIRAL (US), HYBRID (Russia) • Modelling of fast particle (a, ICRH, NBI) ripple losses and resulting first wall heat load in ITER (scenarios 2 and 4, at full and half field) • ITER: new design of FI (and magnetic field map) needed now! • investigate the TBM effect on fast ion orbits/magnetic structure based on a vacuum field including the effect of plasma currents with ASCOT (Finland):ITER: vacuum fields with TBMs and plasma currents ??? • generation of 3d equilibria (VMEC) with the above vacuum field and related fast ion losses (US and Germany) • effect of ELM mitigation coils on fast ion losses

  10. Working plan for ripple induced fast ion losses • 2010-2011 • parametric studies of heat loads caused by TBMs depending on their position, shape and size • investigate possibilities of mitigation of TBM generated perturbation fields by additional coils/ELM mitigation coils • Include self-consistent electric fields on a particle confinement

  11. Effect of collective instabilities onenergetic ion losses • Predict fast ion power loss in ITER inductive, hybrid and steady-state scenarios caused by collective instabilities (AEs, EPMs, Fishbones) • Predict first wall power load in ITER scenarios caused by fast ion loss resulting from collective instabilities • Assess effects of error magnetic fields and ELM mitigation coils on fast ion loss in ITER • Apply non-linear codes to model bursting character in time and rapid chirping in frequency of collective instabilities as observed in experiments Mukhovatov, October 2008

  12. Reliable prediction of fast ion losses induced by collective instabilities requires well developed codes and detailed comparisons with experiments! • What is the status? • good agreement for AE frequency and eigenfunctions between experiments and linear codes vanZeeland, Heidbrink

  13. Reliable prediction of fast ion losses induced by collective instabilities requires well developed codes and detailed comparisons with experiments! • To be done: • drive and damping rates? • - much more complex as kinetic effects involved! • start with code-code comparisons • compare with measured damping rates, in particular at medium n numbers (use excitation coils) • non-linear redistribution of fast ions by AE • energetic particle driven modes

  14. Work plan: linear physics • benchmark exercise of linear codes (damping rates, eigenfunctions, based on well diagnosed JET discharge with measured damping rates – december 08!!!! • LIGKA (Germany), NOVA-K (US), CASTOR-K (EU), TAEFL (US), LEMan (Switzerland), TASK/WM(Japan) (2009) • joint experiments (EP-1) “Comparison of measured damping rates with code results” (2009/2010) • - JET, MAST, Alcator C-Mod, NSTX (coils), ASDEX Upgrade (beat wave excitation) • well diagnosed plasmas and measurement of eigenfunction needed • prediction for AE wave damping rates in ITER based on dedicated experiments and code results (2010/2011)

  15. Non-linear physics Redistribution of fast ions by multiple modes • diagnostics and models/codes being improved • BUT: still many unsolved problems

  16. Work plan: non-linear physics • benchmark exercise of non-linear codes (for simple analytical test case: (2009)) • NOVA-K (US), MEGA (Japan), HAGIS (UK), HMGC (Italy), TAEFL (US), M3D (US), NIMROD (US) • benchmark exercise for a realistic test case (2010) • joint experiments EP-2 “Comparison of code predictions and measurements for fast particle redistribution by Alfven waves and energetic particle modes” • JET, NSTX, ASDEX Upgrade, DIII-D, MAST, Alcator C-Mod, (2009/2010) • use of refined diagnostic for fast ion redistribution/losses • further dedicated experiments/code improvements to allow for reliable predictions of fast ion losses by multi-mode/EP modes in combination with ripple losses (2011 and beyond)

  17. Other topics in cooperation with other TG • Interaction of fast ions with background MHD (in cooperation with MHD) • EP contribution in particular for: • a particle stabilization of sawteeth • redistribution of fast ions by sawteeth and magnetic islands • NBI and a-particle heating and current drive (in cooperation with IOS) • EP contribution: improve physics understanding, in particular for NBI current drive at high heating power • fast ion redistribution by MHD modes • influence of turbulence? • runaway electrons (in cooperation with MHD) • support for MHD-TG where needed • common meetings to ensure good collaboration

  18. Immediate support needed by ITER-IO/Labs? • new design for FIs (promised for November 08) – ITER-IO • vacuum magnetic field with TBM effects (and plasma currents) – ITER-IO • well diagnosed JET discharge as benchmark case for damping rates • (planned for December 08?)

  19. Modelling support needed by Labs? • Ripple losses: • F3D OFMC (Japan), ASCOT (Finland), ORBIT (US), SPIRAL (US), HYBRID (Russia), VMEC (US, Germany) • Benchmarks and urgent ITER predictions for ripple and TBM effects • to be finished in 2009!!! • Damping rates • LIGKA (Germany), NOVA-K (US), CASTOR-K (EU), TAEFL (US), LEMan (Switzerland), TASK/WM(Japan)(2009) • non-linear codes • NOVA-K (US), MEGA (Japan), HAGIS (UK), HMGC (Italy), TAEFL (US), M3D (US), NIMROD (US)(2009/2010)

  20. Joint experiments: • EP-1 “Comparison of measured damping rates with code results” (2009/2010) • JET (before shutdown, new coils?, eigenfunction), • MAST (avoid overlapping modes, eigenfunction) • Alcator C-Mod ?? (separate different n modes) • NSTX (coils) • ASDEX Upgrade (beat wave excitation) • EP-2 “Comparison of code predictions and measurements for fast particle redistribution by Alfven waves and energetic particle modes” • (2009/2010) • JET, NSTX, ASDEX Upgrade, DIII-D, MAST, • Alcator C-Mod?? • use of refined diagnostic for fast ion redistribution/losses • Further experiments to be planned for 2010 (next meeting)

  21. ITER magnetic field structure

  22. Magnetic geometries with maximum ripple

  23. Simulated wall loads forScenario-2 (P = 94MW) & Scenario-4 (P = 52MW) About 100 000 test ions/simulation HP CP4000 BL ProLiant supercluster, 10.6Tflop/s, 256 processors: 24h

  24. Field line around (4,3) island  Island structure is a result of discrete ‘kicks’ In front of a TBM

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