1 / 26

ASDEX Upgrade: Recent hardware upgrades

ASDEX Upgrade: Recent hardware upgrades. extended pulse length to 10 s current flattop (= 2-3 t R even at 10 keV) extended PF coil operational window to run < d> = 0.55 discharges developed ICRH to routinely deliver > 5 MW in ELMy H-mode

dora
Download Presentation

ASDEX Upgrade: Recent hardware upgrades

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. ASDEX Upgrade: Recent hardware upgrades • extended pulse length to 10 s current flattop (= 2-3 tR even at 10 keV) • extended PF coil operational window to run <d> = 0.55 discharges • developed ICRH to routinely deliver > 5 MW in ELMy H-mode • increased W coverage of inner wall (70%): centerpost, upper divertor and PSL

  2. ASDEX Upgrade: Recent hardware upgrades • extended pulse length to 10 s current flattop (= 2-3 tR even at 10 keV) • extended PF coil operational window to run <d> = 0.55 discharges • developed ICRH to routinely deliver > 5 MW in ELMy H-mode • increased W coverage of inner wall: centerpost, upper divertor and PSL Note: new fast steerable ECRH launcher has been installed during last opening

  3. ASDEX Upgrade: Recent hardware upgrades • extended pulse length to 10 s current flattop (= 2-3 tR even at 10 keV) • extended PF coil operational window to run <d> = 0.55 discharges • developed ICRH to routinely deliver > 5 MW in ELMy H-mode • increased W coverage of inner wall: centerpost, upper divertor and PSL • commissioned / started development of new diagnostics: • Doppler reflectometry • Edge Ti from Li beam • Ultrafast (ns) Thomson digitisation for filament detection • Collective Thomson Scattering (Risø, development started) • Fast ion loss detector (first light last week)

  4. High Z PFC development 5 MW (3.7 GHz) The future: preparing ITER operation

  5. EU Associations play active role in the programme

  6. Task Forces in 2003/2004

  7. Understanding of Transport

  8. Understanding the density peaking • Density peaking shows a variation with density itself • Low density L-modes with strong electron heating: 'density pump-out' (!) • Density dependence well described by dependence on neff = nei / wDe • (curvature drift frequency wDe provides estimate of ITG/TEM growth rate)

  9. Difference between particle and heat transport • ITG dominated transport should peak density profile • TEM dominated transport should flatten density profile • Method to discriminate between different modes – looks promising

  10. Active NTM Control

  11. Direct ECCD stabilisation – impact on ITER ASDEX Upgrade experimental points ITER upper ECRH launcher design • ASDEX Upgrade results impact design of ITER ECRH launcher • design requirements based on extrapolation of experimental results • strong interaction with design team • In addition: explore alternative NTM control methods

  12. Frequently Interrupted Regime (FIR) NTMs Pure (3,2) NTM Full symbols: JET Open symbols: ASDEX Upgrade (3,2) coupled to (4,3) FIR regime similar in dimensionless parameters (JET and ASDEX Upgrade) Physics: 3-wave coupling to ideal (m+1,n+1) instability reduces NTM

  13. Transition to FIR NTMs can be induced by ECCD =const. (power control) co-ECCD ctr-ECCD local CD at q=4/3 surface decreases 4/3 stability and provokes FIR NTMs

  14. Sawtooth tailoring by ECCD in ASDEX Upgrade • Experiments with slow Bt-ramp, 0.8 MW co-ECCD and 5.1 MW NBI: • increase of sawtooth period for deposition outside inversion radius • decrease of sawtooth period for deposition inside inversion radius • Ctr-ECCD shows inverse behaviour

  15. Removal of sawteeth avoids NTM during ECCD pulse Bt ramp + feedback controlled b-ramp maintain correct ECCD deposition

  16. Active ELM Control

  17. Triggering ELMs by pellet injection Injection of small pellets at high velocity triggers type I ELMs With pellet repetition rate higher than ELM frequency, control is achieved

  18. Other ELM control methods: supersonic jet (1.5 km/s) Collaboration with CEA Cadarache • Delay time between injection and ELM decreases with amount of gas • Pellet triggered ELMs show much less delay (favourable to minimise losses) • Note: supersonic gas jet has a high fuelling efficiency (> 50%)!

  19. Other ELM control methods: plasma 'wobbling' A slight wobbling of the z-position can lock the type I ELM frequency Locking demonstrated over a surprisingly wide range (up and down) Note: ELM triggered during downward motion (contrary to TCV!)

  20. Other ELM control methods: ECRH modulation

  21. Scenario Development

  22. Beyond standard H-mode: the improved H-mode • confinement improved by density peaking (no sawteeth, fishbones) • NTM onset is high (shaping?) and high b operation leads to FIR NTMs • compatible with type II ELM power exhaust

  23. 0.7 0.6 0.5 0.4 H89 betaN / (q95**2) 0.3 0.2 0.1 0 0 .2 .4 .6 .8 1 1.2 1.4 sqrt(eps) betap Application to ITER: hybrid operation at higher q Longer pulses ITER 1.4 • At fixed geometry and Bt: nTt scales like bN H / q952 • H=1.2 and bN=2.15 allow to drop Ip from 15 MA to 12 MA (q95 up to 3.8) • pulse length more than doubles at constant Pfus and Q ('hybrid' operation)

  24. Application to ITER: hybrid operation at higher q 0.7 Duration longer 10 conf. times 0.6 Longer pulses 0.5 ITER 0.4 H89 betaN / (q95**2) 0.3 0.2 0.1 0 0 .2 .4 .6 .8 1 1.2 1.4 sqrt(eps) betap • At fixed geometry and Bt: nTt scales like bN H / q952 • H=1.2 and bN=2.15 allow to drop Ip from 15 MA to 12 MA (q95 up to 3.8) • pulse length more than doubles at constant Pfus and Q ('hybrid' operation)

  25. Application to ITER: high Q operation (at low q) 0.7 Higher fusion power 0.6 0.5 ITER 0.4 H89 betaN / (q95**2) 0.3 0.2 0.1 0 0 .2 .4 .6 .8 1 1.2 1.4 sqrt(eps) betap • At fixed geometry Bt, and IP, H=1.2 and bN=2.55 double Pfus and Q • this scenario has the potential to become the new ITER reference • world wide effort is under way (ASDEX Upgrade, DIII-D, JET, JT-60U)

  26. 0.7 q-range 3-4 0.6 4-5 5-6 6-7 0.5 7-8 0.4 H89 betaN / (q95**2) 0.3 0.2 0.1 0 .1 .2 .3 .4 .5 .6 .7 .8 .9 1 1.1 1.2 sqrt(eps) betap Application to ITER: high Q operation (at low q) Higher fusion power Recent progress ITER • Note (1): lower q emphasises higher nTt • Note (2): similarity not perfect, ITER has somewhat stronger shaping

More Related