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UKAEA-CCFE-CP(23)402022
Shattered pellet injection (SPI), with research started in recent years, is the current concept for the ITER disruption mitigation system (DMS) to prevent disruption-related damage. Compared with impurity SPI, pure deuterium (D2) SPI could contribute to runaway electron (RE) avoidance in ITER via a strong dilution cooling before the thermal quen…
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UKAEA-CCFE-PR(22)312022
Unusually high power loads on the Beryllium limiter caused by Neutral Beam re-ionisation, and much cooler divertor target surfaces were observed during the recent JET tritium campaign. As both phenomena are driven by scrape-off layer (SOL) physics, the SOL features of 72 tritium H-mode discharges and their deuterium references have been studied. …
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UKAEA-CCFE-CP(23)132021
JET has investigated one the key issues for the baseline scenario in ITER, the integration of a radiative divertor for heat load control with the use of neon and nitrogen as seed impurity. A characterization of the choice of the impurity seed on plasma confinement, neutrons, pedestal MHD stability, pedestal instabilities, core transport is given…
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UKAEA-CCFE-CP(21)072021
The disruption mitigation system at ITER will include four shattered pellet injectors (SPI), which will be dedicated to the mitigation of electro-magnetic loads (EML), thermal loads and the avoidance and suppression of runaway electrons. Recently the JETILW was equipped with an SPI with a wide capability. Specifically: pellet diameter d = [4.57, 8.…
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UKAEA-CCFE-PR(21)712020
In this paper, the pixelated phase mask (PPM) method of interferometry is applied to coherence imag-ing (CI) — a family of passive, narrowband spectro-polarimetric imaging techniques for diagnosing plasmas. Compared to designs using a linear phase mask, PPM is more compact, rugged and has a higher spatial resolution (averaged across both image…
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2020
A robust impurity detection and tracking code, able to generate large sets of dust tracks from tokamak camera footage, is presented. This machine learning–based code is tested with cameras from the Joint European Torus, Doublet-III-D, and Magnum-PSI and is able to generate dust tracks with a 65–100% classification accuracy. Moreover, the number…
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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-PR(20)1202019
A Doppler coherence imaging spectroscopy diagnostic has been developed on the HL- 2A tokamak for scrape-off-layer impurity plasma flow measurements. Two- dimensional imaging of line-averaged C2+ flow in the high-field-side scrape off layer with time resolution up to 1 ms, has been achieved successfully by this system. The spatial angular resolut…
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UKAEA-CCFE-PR(20)192019
A study of mixed hydrogen-deuterium H-mode plasmas has been carried out in JET-ILW to strengthen the physics basis for extrapolations to JET D-T operation and to support the development of strategies for isotope ratio control in future experiments. Variations of input power, gas fuelling and isotopic mixture were performed in H-mode plasmas of the…
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UKAEA-CCFE-CP(20)832018
The authors exposed a radiatively cooled, lithium-filled tantalum heat pipe (HP) to a hydrogen plasma in DIFFER’s linear plasma source Magnum PSI continuously for ~2 hours. The beam made a saddle-shaped footprint along the side of the inclined ~195-mm-long HP. During several steps with constant overall heat load, we tilted the HP to vary the peak…
Showing 11 - 20 of 33 UKAEA Paper Results