Speaker
Description
During the second Deuterium-Tritium campaign (DTE2) at the Joint European Torus (JET), critical physical phenomena relevant to ITER operations were extensively studied. Among these, the detection and analysis of fusion-born alpha particles were of particular importance due to their role in plasma self-heating [1, 2]. This work presents a novel diagnostic approach leveraging bulk electron heating to detect alpha particles [1]. The method employed modulated ion cyclotron resonance heating (ICRH) under a fundamental deuterium scheme in tritium-rich hybrid plasmas with deuterium neutral beam injection (NBI) [3, 4]. The modulation of the iontemperature ($T_i$) and of the ICRH accelerated deuterons leads to modulated alpha particle production. Fusion-born alpha particles, characterized by their high energy, predominantly transfer energy to bulk electrons, resulting in a measurable phase delay between the electron temperature ($T_e$) and $T_i$. By optimizing the plasma conditions for dominant collisional ion heating, other electron heating mechanisms were minimized, isolating the alpha particle contribution. A significant phase delay of approximately 40º was observed between central $T_e$ and $T_i$, providing direct evidence of alpha particle heating. Integrated modelling using frameworks such as ETS, TRANSP, and JINTRAC qualitatively reproduces the observed behaviour, supporting the experimental findings. This diagnostic technique represents a promising tool for alpha particle detection in fusion plasmas, especially in dominant collisional ion heating scenarios.
*See the author list of Maggi et al 2024 Nucl. Fusion 64 112012
[1] P. Mantica et al 2024 Nucl. Fusion 64 086001
[2] V. Kiptily et al 2023 Phys. Rev. Lett. 131, 075101
[3] J. Hobirk et al 2023 Nucl. Fusion 63 112001
[4] M. Maslov et al 2023 Nucl. Fusion 63 112002
| Presentation type | Oral |
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