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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-PR(25)3362025
A method for determining the fast-ion population density in magnetically confined plasmas as a function of pitch-radius, (λ, R), using a solid-state neutral-particle analyzer (ssNPA) signal and neutral-beam injection (NBI) power-output data has been developed. Oscillations in the NBI power output are replicated only in the active part of the ssN…
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UKAEA-CCFE-PR(25)3932024
A Fast-Ion Loss Detector (FILD) was installed for the first time at the MAST-U spherical tokamak during its upgrade in 2021. A CMOS camera was installed in the MAST-U FILD acquisition system to provide high spatial resolution (1.1 MPx) to infer the velocity space of the fast-ion losses. This camera allows up to 3.5 kHz ac…
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UKAEA-CCFE-PR(25)3512024
Fast ion (FI) loss properties in the presence of tearing mode and internal kink perturbations are numerically investigated for discharges in the MAST-U spherical tokamak, utilizing the MARS-F magnetohydrodynamic stability code and the REORBIT test particle guiding-center orbit-following module. Tracing about
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UKAEA-CCFE-PR(25)3442024
By analysing the relative neutron rates measured between multiple fission-chamber (FC) diagnostics – constituting a Fission-Chamber Array (FCA) – the spacial distribution of fusion within a tokamak may be studied. Using the two-FC set-up at MAST-U, analysis methods are presented for both the study of poloidal neutron-emissivity distributions an…
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UKAEA-CCFE-PR(24)2652024
Dedicated experiments were performed on MAST Upgrade to study beam-ion losses caused by charge exchange (CX) with edge neutrals. The fuelling was switched from the high-field side to the low-field side mid-discharge. Direct measurements suggest a strong increase in neutral density around the plasma and a deterioration of the beam-ion confinement…
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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(24)2472023
The JET hybrid scenario has been developed from low plasma current carbon wall discharges to the record-breaking Deuterium-Tritium plasmas obtained in 2021 with the ITER-like Be/W wall. The development started in pure Deuterium with refinement of the plasma current, and toroidal magnetic field choices and succeeded in solving the heat load challeng…
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UKAEA-CCFE-CP(24)112023
The first scintillator-based Fast-Ion Loss Detector (FILD) was installed in MAST-U as part of its main upgrade and it was commissioned during the first experimental campaign. FILD works as a magnetic spectrometer, directly measuring neutral beam injection (NBI) fast-ion losses using a scintillator plate that emits light when fast ions impinge on it…
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UKAEA-STEP-PR(24)012023
Showing 1 - 10 of 78 UKAEA Paper Results