A new upper divertor with internal coils for ASDEX upgrade – Status of the project

Herrmann, A.; Teschke, M.; Zammuto, I.; Cuevas, Maximiliano; Dibon, M.; Kallenbach, A.; Lunt, T.; Rohde, V.; Schall, G.; Vierle, T.; Vorbrugg, S.; Weissgerber, M.; Zohm, H.

doi:10.1016/j.fusengdes.2019.01.114

Cited by 14 publications

(4 citation statements)

References 4 publications

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“…The vacuum vessel is suspended by eight rods equipped with strain gauges to measure their elongation [46]. This value can be related to a force by Hooke's law given by:…”

Section: Forcesmentioning

confidence: 99%

Experiments and non-linear MHD simulations of hot vertical displacement events in ASDEX-Upgrade

Schwarz

Artola²,

Hoelzl³

et al. 2023

Plasma Phys. Control. Fusion

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Hot Vertical Displacement Events (VDEs) are one of the worst case scenarios for high current tokamaks as they are associated with large heat loads and electro-magnetic forces. Non-linear magneto-hydrodynamic (MHD) simulations of the thermal and current quench can help to understand their dynamics and consequences. In order to make predictions for future devices, the validation of codes against present machines is crucial.Dedicated experiments were performed in ASDEX Upgrade to provide a basis for simulations with the non-linear extended MHD code JOREK. 2D as well as non-axisymmetric simulations at realistic parameters can reproduce quantities like the edge safety factor $q_{95}$ at the thermal quench (TQ) onset, the halo current magnitude and the level of vertical forces, while the exact width of the halo current area requires more sophisticated boundary conditions and is left for future work. Small horizontal forces are observed during the hot VDEs in the experiment as well as in the simulations.

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“…The vacuum vessel is suspended by eight rods equipped with strain gauges to measure their elongation [46]. This value can be related to a force by Hooke's law given by:…”

Section: Forcesmentioning

confidence: 99%

Experiments and non-linear MHD simulations of hot vertical displacement events in ASDEX-Upgrade

Schwarz

Artola²,

Hoelzl³

et al. 2023

Plasma Phys. Control. Fusion

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“…The radiative L-mode scenario could be further developed, in a predict-first approach with simultaneous integrated modelling efforts like the one performed here. More efficient radiators [4], active XPR control [111] and the new AUG upper divertor [112] (starting late 2024) could be leveraged in future experiments.…”

Section: Discussionmentioning

confidence: 99%

Full-radius integrated modelling of ASDEX Upgrade L-modes including impurity transport and radiation

Fajardo,

Angioni,

Dux

et al. 2024

Nucl. Fusion

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An integrated framework that demonstrates multi-species, multi-channel modelling capabilities for the prediction of impurity density profiles and their feedback on the main plasma through radiative cooling and fuel dilution is presented. It combines all presently known theoretical elements in the local description of quasilinear turbulent and neoclassical impurity transport, using the models TGLF-SAT2 and FACIT. These are coupled to the STRAHL code for impurity sources and radiation inside the ASTRA transport solver. The workflow is shown to reproduce experimental results in full-radius L-mode modelling. In particular, a set of ASDEX Upgrade L-modes with differing heating power mixtures and plasma currents are simulated, including boron (B) and tungsten (W) as intrinsic impurities. The increase of predicted confinement with higher current and the reduction of core W peaking with higher central wave heating are demonstrated. Furthermore, a highly radiative L-mode scenario featuring an X-point radiator (XPR) with two intrinsic (B, W) and one seeded argon (Ar) species is simulated, and its measured radiated power and high confinement are recovered by the modelling. The stabilizing effect of impurities on turbulence is analyzed and a simple model for the peripheral X-point radiation is introduced. A preliminary full-radius simulation of an H-mode phase of this same discharge, leveraging recent work on the role of the E×B shearing at the edge, shows promising results.

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“…AUG is currently embarking on a substantial enhancement of the upper divertor co-funded by EUROfusion [133,134]. The new upper divertor (see figure 20(c)) is in its final design stage and will be implemented during a long shutdown starting 2021.…”

Section: Discussionmentioning

confidence: 99%

Overview of physics studies on ASDEX Upgrade

et al. 2019

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The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m−1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of ‘natural’ no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle—measured for the first time—or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO.

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A new upper divertor with internal coils for ASDEX upgrade – Status of the project

Cited by 14 publications

References 4 publications

Experiments and non-linear MHD simulations of hot vertical displacement events in ASDEX-Upgrade

Experiments and non-linear MHD simulations of hot vertical displacement events in ASDEX-Upgrade

Full-radius integrated modelling of ASDEX Upgrade L-modes including impurity transport and radiation

Overview of physics studies on ASDEX Upgrade

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