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UKAEA-CCFE-CP(20)742020
Post mortem analysis shows that mid and high atomic number metallic impurities are present in deposits on JET plasma facing components with the highest amount of Ni and W, and therefore the largest sink, being found at the top of the inner divertor. Sources are defined as “continuous” or “specific”, in that “continuous” sources…
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UKAEA-CCFE-PR(20)832020
This paper presents results of extensive analysis of mode excitation observed during the operation of the Alfvén Eigenmode Active Diagnostic (AEAD) in the JET tokamak during the 2019-2020 deuterium campaign. Six of eight toroidally-spaced antennas, each with independent power and phasing, were successful in actively exciting stable MHD modes in…
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UKAEA-CCFE-PR(19)792019
The exhaust (loss) power components due to ELMs, radiation and heat transport across the edge transport barrier (ETB) between ELMs are quantifed for H-mode plasmas in JET-C and JET-ILW to provide data for comparison with simulations of pedestal heat transport. In low-current, JET-ILW pulses with a low rate of gas fuelling, the pedestal heat tran…
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2019
Data on erosion and melting of beryllium upper limiter tiles, so-called dump plates (DP), are presented for all three campaigns in the JET tokamak with the ITER-like wall. High-resolution images of the upper wall of JET show clear signs of flash melting on the ridge of the roof-shaped tiles. The melt layers move in the poloidal direction from the i…
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UKAEA-CCFE-PR(20)1272019
The self-consistent core-pedestal prediction model of a combination of EPED1 type pedestal prediction and a simple stiff core transport model is able to predict type I ELMy pedestals of a large database JET-ILW (ITER-like wall) at the similar accuracy as is obtained when the experimental global plasma b is used as input. The neutral penetration …
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UKAEA-CCFE-PR(20)1222019
We present an ultrafast neural network (NN) turbulent tokamak transport model, QLKNN, for heat and particle fluxes. QLKNN is a surrogate model based on a database of 3 · 108 flux calculations of the quasilinear gyrokinetic transport model QuaLiKiz. To ensure accurate reproduction of the underlying model, we include known features of the…
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UKAEA-CCFE-CP(20)842019
JET has now completed three operating periods, ILW1, ILW2 and ILW3, giving an opportunity to make comparisons between tiles exposed for single operating periods and also comparisons of tiles exposed for all three periods, ILW1-3 (2011-2016). In this contribution, a comprehensive overview of fuel retention and material erosion/deposition patterns…
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UKAEA-CCFE-CP(20)692019
Elliptical AE (EAE) and TAE mode instabilities have been observed in hydrogen-rich (nH/(nH+nD)~70-90% JET discharges of so-called “three-ion scenario”, i.e. D-(3He)-H three ion ICRH scenario [1], which is characterized by strong absorption of radio frequency waves a…
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UKAEA-CCFE-PR(20)172019
Core turbulent particle transport with multiple isotopes can display observable differences in behaviour between the electron and ion particle channels. Experimental observations at JET with mixed H-D plasmas and varying NBI and gas-puff sources [M. Maslov et al., Nucl. Fusion 7 076022 (2018)] inferred source dominated electr…
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2018
The first divertor was installed in the JET machine between 1992 and 1994 and was operated with carbon tiles and then beryllium tiles in 1994–5. Post-mortem studies after these first experiments demonstrated that most of the impurities deposited in the divertor originate in the main chamber, and that asymmetric deposition patterns generally favou…
Showing 71 - 80 of 223 UKAEA Paper Results