1. Overview of ASDEX upgrade results in view of ITER and DEMO
- Author
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the ASDEX-Upgrade team, Eurofusion Tokamak Exploitation Team, Zohm, H., Alessi, E., Angioni, C., Arden, N., Artigues, V., Astrain, M., Asunta, O., Balden, M., Bandaru, V., Banon Navarro, A., Blanken, T., van den Brand, H., de Baar, M., Felici, F., Jaulmes, F., Kappatou, A., Krebs, I., Linder, O., Maljaars, E., Scholte, J., Shabbir, A., Vanovac, B., Wagner, D., the ASDEX-Upgrade team, Eurofusion Tokamak Exploitation Team, Zohm, H., Alessi, E., Angioni, C., Arden, N., Artigues, V., Astrain, M., Asunta, O., Balden, M., Bandaru, V., Banon Navarro, A., Blanken, T., van den Brand, H., de Baar, M., Felici, F., Jaulmes, F., Kappatou, A., Krebs, I., Linder, O., Maljaars, E., Scholte, J., Shabbir, A., Vanovac, B., and Wagner, D.
- Abstract
Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER and EU DEMO. A major objective of the AUG programme is to shed light on the underlying physics of confinement, stability, and plasma exhaust in order to allow reliable extrapolation of results obtained on present day machines to these reactor-grade devices. Concerning pedestal physics, the mitigation of edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found to be consistent with a reduction of the linear peeling-ballooning stability threshold due to the helical deformation of the plasma. Conversely, ELM suppression by RMPs is ascribed to an increased pedestal transport that keeps the plasma away from this boundary. Candidates for this increased transport are locally enhanced turbulence and a locked magnetic island in the pedestal. The enhanced D-alpha (EDA) and quasi-continuous exhaust (QCE) regimes have been established as promising ELM-free scenarios. Here, the pressure gradient at the foot of the H-mode pedestal is reduced by a quasi-coherent mode, consistent with violation of the high-n ballooning mode stability limit there. This is suggestive that the EDA and QCE regimes have a common underlying physics origin. In the area of transport physics, full radius models for both L- and H-modes have been developed. These models predict energy confinement in AUG better than the commonly used global scaling laws, representing a large step towards the goal of predictive capability. A new momentum transport analysis framework has been developed that provides access to the intrinsic torque in the plasma core. In the field of exhaust, the X-Point Radiator (XPR), a cold and dense plasma region on closed flux surfaces close to the X-point, was described by an analytical model that provides an understanding of its formation as well as its stability, i.e., the conditions under which it transitions into a deleterious MARFE with the potential to re
- Published
- 2024