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UKAEA-CCFE-PR(26)4262025
The first results of studies of high-power (≥ 3 MW) H-mode discharges in double-null X-point-target (XPT) divertor configuration on MAST-U are presented. By combining the large strike point radius of the Super- X divertor with an additional X-point in the baffled outer divertor chambers, further exhaust benefits in strongly detached conditions…
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UKAEA-CCFE-PR(26)4232025
The MAST Upgrade Super-X divertor protects plasma-facing components from heat fluxes during steady-state operation and transient events. This paper examines heat loads from sawtooth events with energies of ΔWsawtooth ≈ 2–9 kJ in lower single null plasmas. The impact of deuterium and nitrogen gas pressures on mitigating these transients is inve…
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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)3052025
The MAST Upgrade Super-X divertor is typically seen to detach in steady state discharges. However, divertor re-attachment is observed to occur during fast transient heat loads. In this paper the effect of edge localised modes (ELMs) on the divertor are diagnosed on fast time scales with Thomson scattering and with a new ultrafast divertor spectrosc…
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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)3692024
Plasma detachment in tokamaks is useful for reducing heat flux to the target. It involves interactions of the plasma with impurities and neutral particles, leading to significant losses of plasma power, momentum, and particles. Accurate mapping of plasma emissivity in the divertor and X-point region is essential for assessing the rel…
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UKAEA-CCFE-PR(25)3602024
Determination of the absolute neutron rate production in any fusion device and in particular for ITER and future power plants is essential for their operation and for the optimization of the fusion power. A common calibration approach is to use a well characterized neutron sources placed inside the vacuum vessel combined with Monte Carlo simula…
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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…
Showing 1 - 10 of 30 UKAEA Paper Results