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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)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-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-CP(26)322024
Tikhonov regularization has so far been the method par excellence applied to Fast Ion Loss Detector (FILD) [1] measurements to obtain an accurate fast ion velocity distribution [2]. To address two major drawbacks of Tikhonov regularization, the computational expense and the critical reliance on the optimal value of a hyperparameter, iterative algor…
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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(24)2612024
The fusion reaction between deuterium and tritium, D(T,n)4He is the main source of energy in future thermonuclear reactors. Alpha-particles (4He-ions) born with an average energy of 3.5MeV transferring energy to the thermal plasma during their slowing down, they should provide the self-sustained D-T
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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…
Showing 1 - 10 of 16 UKAEA Paper Results