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UKAEA-CCFE-CP(23)442022
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
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UKAEA-CCFE-PR(23)102022
The fusion-born alpha-particle heating in magnetically confined fusion machines is a high priority subject for study. The self-heating of thermonuclear fusion plasma by alpha-particles was observed in recent deuterium-tritium (D-T) experiments on the Joint European Torus (JET). This observation was possible by conducting so-called “af…
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UKAEA-CCFE-CP(23)312021
Alfvén eigenmode (AE) instabilities driven by α-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall [Kiptily et al, submitted to Phys. Rev. Letters, 2020]. The impact of these type instabilities on a burning plasma is of crucial relevance for the perfor…
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UKAEA-CCFE-PR(21)782021
Alfvén eigenmode (AE) instabilities driven by alpha-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall (ILW). For the efficient generation of fusion alpha-particles from D-3He fusion reaction, the 3‑ion radio frequency (RF) scenario was used t…
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UKAEA-CCFE-PR(21)362021
The interaction of Alfvén Eigenmodes (AEs) and energetic particles will determine the success of future tokamaks. In JET, eight in-vessel antennas were installed to actively probe stable AEs with frequencies ranging 25 – 250 kHz and toroidal mode numbers abs(n)< 20. During the 2019-2020 deuterium campaign, almost 7500 resonances and …
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UKAEA-CCFE-PR(21)302021
Recent JET Deuterium experiments with an advanced internal transport barrier (ITB) scenario have been performed to clearly observe destabilised toroidicity-induced Alfvén eigenmodes (TAEs) by fast ions; interestingly, these also exhibit unstable electromagnetic (EM) perturbations in the sub-TAE frequency range. We identify such EM perturbations to…
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UKAEA-CCFE-PR(21)212021
In this work, we use reduced and perturbative models to examine the stability of TAEs during the ITB afterglow in JET experiments designed for the observation of alpha driven TAEs. We demonstrate that in JET-like conditions, it is sufficient to use an incompressible cold plasma model for the TAE to reproduce the experimental adiabatic features…
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UKAEA-CCFE-CP(20)712020
The fast-ion transport has been investigated in low-collisionality discharges at ASDEX Upgrade and TCV using offaxis neutral beams. In both devices Alfven eigenmode activity was observed which does, however, not strongly affect the global fast-ion confinement. In contrast, charge exchange losses have been identified to have a strong effect. At TCV …
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UKAEA-CCFE-PR(20)1312020
This paper presents a dedicated study of plasma-antenna (PA) coupling with the Alfvén Eigenmode Active Diagnostic (AEAD) in JET. Stable AEs and their resonant frequencies f, damping rates < 0, and toroidal mode numbers n are measured for various PA separations and limiter versus X-point magnetic cofigurations. Two stable AEs are observed to be …
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UKAEA-CCFE-PR(20)1002020
Dedicated experiments to generate high-energy D ions and D-3He fusion-born alpha particles have been performed at the Joint European Torus (JET) with the ITER-like wall (ILW). Deuterium ions from neutral beam injection (NBI) with acceleration voltage of 100 keV were accelerated to higher energies in the core of mixed D-3He…
Showing 21 - 30 of 80 UKAEA Paper Results