Description
In tokamak disruptions, a runaway electron (RE) beam carrying multiple MAs of current in the form of multi-MeV electrons poses an intolerable risk to plasma-facing components. Knowledge of the RE distribution function is necessary to test the performance of mitigation schemes. Previous studies of the RE distribution based on synchrotron imaging have been performed in AUG1 and TCV2. To further explore RE physics and mitigation concepts, RE expulsion from the plasma core using ECRH has recently been investigated in TCV3.
We study the RE transport by approximating RE diffusion coefficients using Bayesian optimisation on DREAM fluid simulations4. This helps to reduce the parameter space before implementing the same approach on kinetic simulations that are significantly more expensive to run. Using the simulated distribution functions we generate synthetic synchrotron radiation images using SOFT5.These images are then compared to the experimental measurements that were performed using a multi-spectral imaging system (MANTIS6).
In this contribution we summarise the RE scenario under ECRH in TCV and the DREAM and SOFT modelling results, including a comparison of experimental and synthetic synchrotron images. We also discuss the approximated RE diffusion under ECRH.
References
[1] M. HOPPE ET AL. Journal of Plasma Physics, 87 (1):855870102 (2021).
[2] T. WIJKAMP ET AL. Nuclear Fusion, 61 (4):046044 (2021).
[3] J. DECKER ET AL. Nuclear Fusion, 64 (10):106027 (2024).
[4] M. HOPPE ET AL. Computer Physics Communications, 268:108098 (2021).
[5] M. HOPPE ET AL. Nuclear Fusion, 58 (2):026032 (2018).
[6] A. PEREK ET AL. Review of Scientific Instruments, 90 (12):123514 (2019).