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UKAEA-CCFE-PR(26)4302026
In the paper we present validated integrated modelling of JET experiments in which fusion performance is driven by reactions between fast ions and intrinsically present metal wall impurities. A steady-state L-mode plasma with dominant proton-beryllium fusion and neutron yields of up to ≈ 6 x 1013 s-1 is developed in He and D…
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UKAEA-CCFE-PR(26)4222025
Dedicated experiments were conducted on Alfvénic instabilities in the ion sub-cyclotron frequency range excited by energetic beam ions in the MAST-Upgrade tokamak. Losses of the beam ions associated with plasma instabilities were measured with a scintillator-type fast ion lost detector (FILD), which provided a 2D image of the losses as functions o…
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UKAEA-CCFE-PR(25)4002025
The first measurements of energetic particle-driven ion cyclotron emission (ICE) in the Mega-Amp Spherical Tokamak Upgrade (MAST-U) have been obtained by adding a high sampling rate (250MHz) capability to one coil of the existing OMAHA array, oriented to measure fluctuations in the toroidal magnetic field component. All these measurements were carr…
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UKAEA-CCFE-PR(25)3422025
We report the observation and analysis of ion cyclotron emission (ICE) in the Wendelstein 7-X (W7-X) stellarator during discharges without a significant fast-ion population. In these experiments, ICE is observed using the strap of the ICRF antenna, while remaining undetectable on the B-dot probes during ECRH-only phases. At low electron densities, …
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UKAEA-CCFE-CP(26)342024
The MAST-U spherical tokamak (ST) is equipped with on-axis and off-axis neutral beam injectors (NBI), external sources of super-Alfvénic fast ions that provide opportunities for studying a wide range of phenomena relevant to the physics of alpha-particles in future burning plasma devices such as STEP or ITER. High performance of MAST-U plasmas rel…
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UKAEA-CCFE-PR(24)2152024
The first observations and classification of sub-cyclotron frequency range Alfvén eigenmodes (AEs) are presented for the MAST Upgrade tokamak. Sets of observed eigenmodes are separated by approximately 200 kHz. We observe a low frequency separation of ~10 kHz within the set, and the toroidal mode number n increases with frequency sequentially. …
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UKAEA-CCFE-CP(25)282023
MAST-U is equipped with on-axis and off-axis neutral beam injectors (NBI), external sources of super-Alfvénic fast-ions that provide opportunities for studying a wide range of phenomena relevant to the physics of alpha-particles in burning plasmas. Clear evidence of fast-ion redistribution and loss due to sawteeth (ST), fishbones (FB), long-liv…
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UKAEA-CCFE-PR(25)2882023
Dedicated experiments were performed in JET DTE2 plasmas for obtaining α-particle bump-on-tail (BOT) distribution aiming at exciting Alfvén Eigenmodes (AEs) in baseline tokamak plasma scenario with safety factor q(0)~1. NBI-only heating with modulated power was used so that fusion-born α-particles were the only ions present in the MeV energy ran…
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UKAEA-CCFE-PR(25)2872023
Fast-particle driven Alfvén Eigenmodes have been observed in low-collisionality discharges with off-axis neutral beam injection (NBI), electron cyclotron resonance heating (ECRH) and a reduced toroidal magnetic field. During NBI and ECRH, toroidicity induced Alfvén Eigenmodes (TAEs) appear in frequency bands close to 200 kHz and energetic-part…
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UKAEA-CCFE-PR(25)2862023
A forward modeling technique is developed for determining the characteristic features of observed MHD modes from the line-of-sight data of the soft x-ray (SXR) diagnostics with 64 vertical lines-of-sight in theTokamak `a Configuration Variable tokamak. Using diagnostics with excellent spatial resolution, this technique is shown to evaluate the polo…
Showing 1 - 10 of 18 UKAEA Paper Results