Speaker
Description
MeV-range Neutral Beams (NBs) in ITER plasmas are essential for heating and sustaining plasma scenarios through, e.g., current-drive and torque injection. However, NB injection into low-density plasmas can result in inefficient beam ionisation and localised high-energy neutral particle losses on the Plasma-Facing Components (PFCs). This well-known phenomenon, shine-through, poses a significant risk to the PFCs’ lifetime. This contribution presents the recent modelling work that led to defining the unrestricted operational boundaries for NB injection in ITER plasmas regarding beam power and energy, preventing excessive power load on PFCs caused by shine-through. The initial ITER NB operations will occur during the DT-1 phase of the new ITER Research Plan, starting with hydrogen (H) injection. This configuration results in nearly double the shine-through losses compared to deuterium (D) injection, limiting the operational space to higher plasma densities. Nevertheless, the recent redesign of the PFCs in the NB footprint area has significantly increased the permitted shine-through power load. Possible NBI power restrictions will be compensated by the increased availability of wave-heating in the new ITER baseline. Through extensive parameter scans using state-of-the-art NB injection modelling codes, we determined the available beam power and the minimum plasma density for unrestricted NB operations as a function of the injected and plasma species, injection energy and plasma density profile peaking. Additionally, the effects of plasma electron temperature and impurity content were evaluated. This work constitutes the basis of a recently started project aimed at employing Artificial Intelligence (AI) and Machine Learning (ML) techniques to develop NB fast particle predictive tools for ITER and JT-60SA NB operations, significantly reducing computational time and resource demands.
| Presentation type | Oral |
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