Speaker
Description
The X-Point Radiator (XPR) regime is a promising exhaust solution for future large-size tokamaks, featuring a cold, dense, highly radiative region above the X-point, inside the confined region. Such regimes have been achieved experimentally on several tokamaks, with different seeded impurities, and ELM suppression is seen when the XPR reaches a threshold height [1]. Modeling with SOLPS-ITER [2], JINTRAC [3], and GRILLIX [4] has successfully reproduced several features seen in experiments. However, existing simulations have not been able to self-consistently study the dynamical interplay between the XPR and the pedestal which results in ELM suppression. For this an MHD code with realistic scrape-of layer (SOL) physics is needed.
In this contribution, we present the current status of modeling of the XPR regime on the ASDEX Upgrade (AUG) tokamak with the visco-resistive nonlinear MHD code JOREK [5]. The longer-term objective of this work is to extend the modeling to ITER provided the AUG validation is favourable. A two-way coupled particle-in-cell model treats neutrals and impurities kinetically, including their interactions with the background fluid plasma [6,7].
Recently this coupling has been extended to the reduced MHD, two-temperature model of JOREK, allowing for benchmarking with other codes and experimental validation. The validation work focuses on the stationary XPR features and ELM suppression. Nitrogen seeded simulations are compared to SOLPS-ITER and AUG experiments, further modeling is presented using different impurity species such as argon and neon.
[1] M. Bernert, et al Nuclear Materials and Energy 43 (2025): 101916.
[2] O. Pan, et al Nuclear Fusion 63.1 (2022): 016001.
[3] S. Q. Korving, et al EPS (2025).
[4] K. Eder, et al, Nuclear Fusion 65.9 (2025): 096029.
[5] M. Hoelzl, et al Nuclear Fusion 64.11 (2024): 112016.
[6] S. Q. Korving, et al Physics of Plasmas 30.4 (2023).
[7] S. Q. Korving, et al Physics of Plasmas 31.5 (2024).
[8] H. Zohm, et al Nucl. Fusion 64 112001 (2024)