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UKAEA-CCFE-PR(26)4552024
The linear MHD peeling-ballooning stability analysis on the ELM-free phase of MAST Upgrade H-mode plasma is presented. In contrast to other similar discharges, #47018 is found to have significantly higher and wider pedestal during an ELM-free H-mode phase that lasts for approximately 80ms, which is made possible by the reduced core MHD mode acti…
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UKAEA-CCFE-PR(25)2972024
During detachment, a buffer of neutral atoms and molecules builds up between the target and the ionising plasma. Collisions between the plasma and the molecules play an important role in the detachment process. Studies of plasma-molecular kinetics indicate that the gas temperature is increased during detachment for a wide range of conditions on …
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UKAEA-CCFE-PR(24)2162023
The first pedestal stability analysis on the new MAST Upgrade (MASTU) spherical tokamak H-mode plasma is presented. Our results indicate that MAST-U pedestals are close to the low toroidal mode number (n) peeling branch of the peelingballooning instability, in contrast with MAST H-mode pedestals which were deeply in the high-n ballooning branch. Th…
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UKAEA-CCFE-PR(23)1632023
High resolution D2 Fulcher band spectroscopy was used in the MAST-U divertors during Super-X and elongated conventional divertor density ramps with D2 fuelling from the mid-plane high-field side. In the Super-X case (density ramp from Greenwald fraction 0.12 to 0.24), the upper divertor showed ground state rotational tempe…
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UKAEA-CCFE-PR(23)1322023
First quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor show an unprecedented impact of plasma-molecular interactions involving molecular ions (likely $D_2^+$), resulting in strong ion sinks, leading to a reduction of ion target flux. This starts to occur as the ionisation source detaches from the target, lea…
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UKAEA-CCFE-PR(23)942022
Divertor detachment requires plasma-neutral interactions which dissipate momentum, power and particles simultaneously. Plasma-molecular interactions can result in molecular ions which react with the plasma. This can contribute to detachment through molecular activated recombination (MAR) and molecular activated dissociation (MAD), both of which cre…
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UKAEA-CCFE-PR(22)232022
In this paper we a first qualitative analysis of the atomic and molecular processes at play during detachment in the MAST-U Super-X divertor, using divertor spectroscopy data. Our analysis indicates a wide operational regime of detachment of the MAST-U super-X divertor, which can be roughly separated in four phases: 1) The ionisation fro…
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UKAEA-CCFE-PR(21)042021
In preparation for the upcoming MAST-U campaign, pedestal stability of spherical tokamaks is revisited by investigating standard H-mode discharges on MAST. As a step beyond previous studies, both ion and electron profiles are used for obtaining equilibria and a diverse set of pedestals is evaluated. Stability analysis with the ELITE and CGYRO codes…
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2012
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2011
Detailed 2D measurements of long-wavelength density fluctuations in the pedestal region with beam emission spectroscopy during the period between edge localized modes (ELMs) indicate two distinct bands of fluctuations propagating in opposite poloidal directions in the plasma frame: one lower frequency band (50–150 kHz) advects in the ion-diamagne…
Showing 1 - 10 of 11 UKAEA Paper Results