ASDEX Upgrade: machine news and progarm for 2025

Summary

This presentation delivered at the EUROfusion General Programme Meeting provides machine status updates and operational plans for ASDEX Upgrade (AUG) in 2024–2025. It covers the vessel restart following a two-year vent, upgrades to neutral beam injection (NBI), pellet injection, and cryopumping systems, as well as new diagnostic capabilities and experimental configurations for the newly installed upper divertor (Div-IIo).

EUROfusion General Programme Meeting Nov 18, 2024: ASDEX Upgrade: machine news and progarm for 2025

EUROfusion General Programme Meeting Nov 18, 2024 ASDEX Upgrade: machine news and progarm for 2025 Arne Kallenbach on behalf of the ASDEX Upgrade team MAX-PLANCK-INSTITUT FÜR PLASMAPHYSIK EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH

AUG vessel closed after 2-year vent on Aug 30th

AUG vessel closed after 2-year vent on Aug 30th Final in-vessel panorama view August 2024 Foto: V. Rohde EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 2)

Finalization of the AUG extension work and restart

Finalization of the AUG extension work and restart • The AUG vessel was closed on Aug 30., followed by leak repairs and baking from Sep 17-27 • Restart began on Oct 8, with a no-op week 42 for re-installation of a repaired transformator • Progress in restart was quite slow: • Very difficult Ip rampup after restart with clean metal surface (+ original control and other issues) • 1.5 days lost due to cooling water problem • Finally Ip=0.4 MA flattop achieved with ECRH assist on Oct 25, albeit high runaway content • Toroidally halved boronization on Oct 28 (joint venture exp EUROfusion-IPP following ITER request): immediate Ip buildup, some shaky breakdowns, good plasma startup after some conditioning pulses • 2.5 days lost Nov 5,7,8 after arc in EZ2 generator motor supply • NBI comissioning slow due to HF problems in box I and delayed installation in box II + HV problem NBI II expected back ~ during Fri Nov 22 EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 3)

NBI upgrades

NBI upgrades • NBI box I switched from arc to RF sources • NBI box II all sources with variable gap (as source 5 in 2022) • Slow commissioning due to some technical issues HV power supply in 65 A/107 kV setting EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 4)

Pellets

Pellets • A number of changes to the system • Slightly changed geometry, refer to diaggeom Launch at: z = 915 mm, R = 1255 mm, Inclination 70.1° (with respect to horizontal plane) • System running so far, but successful delivery ratio too low (80 % in best shot) Probable reason cutter timing, can be varied EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 5)

Characterisation of the new cryopump

Characterisation of the new cryopump • 7 modules • Charcoal coating enables helium pumping Features: Flange connection, Heating conductor, 80K Chevron baffle, 4K Cryopanel, 80K Thermal shield, 4K measuring point, Torlon® 4203 insulating washer EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 6)

Characterisation of the new cryopump - Pumping speed and saturation

Characterisation of the new cryopump Measurement of puming speed and saturation behaviour for D and He Nov 5+6 − Preliminary results from control room perspective (deep analysis still ongoing, report Monday morning ~ Dec 2) − Effective pumping speed for D2 about as expexted (D2: τ1/e ~ 2 s) − Helium pumping due to charcoal coating, put pure He pumping speed less than for D2 (He: τ1/e ~ 7 s) − Effect of He entrainment in D2 flow to be evaluated (Gerd Schall) − Uptake capability for helium is limited ! EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 7)

Diagnostics Status

Diagnostics ▪ most of the diagnostics up and running ▪ ECE currently old data aquisistion, 32 kHz, 7 s – new DAQ system to com online soon ▪ Core Thomson scattering with new 100 Hz laser, preliminary calibration, data written to exp= YAGG till N2 calib. Lower divertor TS expected this week, upper divertor TS next week, afterwards Raman calibration ▪ New bolometry and spectroscopy systems up and running ▪ Upper Helium-beam diagnostic under commissioning ▪ Upper divertor TS coming soon ▪ Tungsten diagnostics from grazing incidence spectr. Online, data written to exp= PUETTI until Thomson data rewritten to AUG EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 8)

New diagnostics

New diagnostics: Langmuir probes IR Thermography Thermocouples NIR & VIS Video Real Time Divertor Thomson Scattering (+EUROfusion) Manometers & gas flow meters Reflectometry Shunt measurements Bolometry Spectroscopy Magnetic probes Dispersion interferometer (disruption studies, 2025) MANTIS in prep. EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 9)

First plasmas in new upper divertor

First plasmas in new upper divertor Equilibria display and in-vessel camera image of plasma operation in the new upper divertor. EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 10)

Preparation of the new Div-IIo

Preparation of the new Div-IIo EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 11)

Many configurations are prepared and partly investigated for performance with predictive modelling (EMC3, SOLPS)

Many configurations are prepared and partly investigated for performance with predictive modelling (EMC3, SOLPS) Configurations shown:

SN (Single Null, 0.0 kAt / 0.0 kAt)
XD (-33.2 kAt / 33.2 kAt)
CRD (-20.2 kAt / 20.2 kAt)
LFS SF- (-47.2 kAt / 47.2 kAt)
HFS SF- (-48.0 kAt / 48.0 kAt)
SF+ (-46.8 kAt / 46.8 kAt) test equilibria for diagnostic development etc. stored as AUG shotfiles (Tilmann Lunts Science Meeting Talk Mar 2023) EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 12)

Prospects for extreme CRD with Div-IIo

Prospects for extreme CRD with Div-IIo Concept / physics:

dissipate power before it reaches the SOL
stabilize radiating region at the X-point (XPR)
Provide neutral plugging
Maximize volume of confined plasma
reduce PF coil currents Challenges:
stabilize position of XPR
shallow field line incidence angles ? EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 13)

ASDEX Upgrade Schedule

ASDEX Upgrade Schedule Restart finished on 15.11., 2nd boronization on 18.11. (or 20.11.), - a few weeks delayed, finally. SPI expected back 12.12. Nov 19 – Dec 18: 2024 program 12 experimental days for proposals, ~ 100 shots

physics experiments, but – no current in new upper divertor coils available End Jan 2025 - development of AD configurations with antisymmetric coil currents ~ March 2025 - integration of AD configurations with AT and no-ELM scenarios (QCE, EDA, RMP, .. ) Spring – summer 2025 - development of coils current feedback (sensors to be defined) Low density program: AT, RMP ELM suppression etc: 7 boronizations in 4 week intervals in 2025 Aug 2025 – Sept or Nov 2025: summer break, vessel opening likely ~ end 2025 differential divertor coil currents EUROfusion WP-TE GPM 18.11.24 | ASDEX UPGRADE | ARNE KALLENBACH (Page 14)