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UKAEA-CCFE-PR(21)082021
A survey of the correlation between temperature and density gradient lengths ( and ) has been performed for the near SOL regions in the ASDEX Upgrade tokamak. In common with previous studies, the near SOL temperature and density gradient length ratio, , is found to be close to unity across a wide range of plasmas. However, it is found that it is po…
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UKAEA-CCFE-PR(21)072021
A study of a dataset of JET plasma with the Be/W ITER-like wall (JET-ILW) shows that reaching the edge MHD ballooning limit leads to confinement degradation. However, unlike JET plasma with a carbon wall (JET-C), the JET-ILW plasma stays in a marginal dithering phase for a relatively long period, associated with a higher a ( 20%) H-mode density lim…
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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-CP(20)1212020
While current tokamak experiments are beginning to utilise real-time feedback control systems to manage the plasma exhaust, future tokamaks still require validation of theoretical models used to predict the threshold impurity concentration required to facilitate stationary divertor operation. This work exploits new spectroscopic measurements of …
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UKAEA-CCFE-CP(20)912020
The experimental validation of turbulence models is a critical part of developing a predictive understanding of plasma transport. Models based on the non-linear gyrokinetic equations are currently the most well understood and experimentally validated models of turbulence available. However, models of reduced complexity are required in order to mak…
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UKAEA-CCFE-PR(20)182019
It is demonstrated that tokamak plasma can be fuelled by pellets while simultaneously maintaining ELM suppression by external resonant magnetic perturbations (RMPs). Pellets are injected from vertical high field site and deposited at outer part of plasma cross section. Each pellet triggers benign MHD event followed by short lived ELM free phase. Th…
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2018
Access conditions for full suppression of edge localised modes (ELMs) by magnetic perturbations (MP) in low density high confinement mode (H-mode) plasmas are studied in the ASDEX Upgrade tokamak. The main empirical requirements for full ELM suppression in our experiments are: 1. The poloidal spectrum of the MP must be aligned for best plasma respo…
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UKAEA-CCFE-CP(20)882018
The ASDEX Upgrade (AUG) programme is geared towards developing the physics basis for ITER and (EU)-DEMO and is jointly executed with the EUROfusion Medium Size Tokamak task force. Integrated scenario development to prepare future device operation, detailed physics studies to improve predictability of fusion devices and testing of fusion relevant t…
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UKAEA-CCFE-PR(20)052019
Resistive plasma response to the n = 1 (n is the toroidal mode number) RMP field is systematically investigated for a high-beta hybrid discharge on ASDEX Upgrade. Both linear and quasi-linear response are modelled using the MARS-F and MARS-Q codes, respectively. Linear response computations show a large internal kink response when the plasma centra…
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UKAEA-CCFE-CP(19)282019
A detailed cross-device investigation on the role of filamentary dynamics in high density regimes has been performed within the EUROfusion framework comparing ASDEX-Upgrade (AUG) and TCV tokamaks. Both devices have run density ramp experiments at different levels of plasma current, keeping toroidal field or q95 constant in order to disentangle the …
Showing 11 - 20 of 52 UKAEA Paper Results