J. W. S. Cook R.O. Dendy S.C. Chapman
A fast Alfven wave with a finite amplitude is shown to grow by a stimulated emission process that we propose for exploitation in toroidal magnetically confined fusion plasmas. Stimulated emission occurs while the wave propagates inward through the outer midplane plasma, where a population inversion of the energy distribution of fusion-born ions is …
Preprint PublishedA. Fernandez-Caballero J.S. Wrobel P.M. Mummery D. Nguyen-Manh
In high-entropy alloys (HEAs), the local chemical fluctuations from disordered solute solution state into segregation, precipitation and ordering configurations are complex due to the large number of elements. In this work, the cluster expansion (CE) Hamiltonian for multi-component alloy systems is developed in order to investigate the dependence o…
Preprint PurchaseL. Yueqiang A. Kirk L. Li Y. In R. Nazikian Y. Sun W. Suttrop B. Lyons D. Ryan S. Wang X. Yang L. Zhou EUROfusion MST1 team
Extensive modelling efforts of the plasma response to the resonant magnetic perturbation fields, utilized for controlling the edge localized mode (ELM), help to identify the edge-peeling response as a key factor, which correlates to the observed ELM mitigation in several tokamak devices, including MAST, ASDEX Upgrade, EAST, and HL-2A. The recently …
PublishedL. Carbajal R. O. Dendy S. C. Chapman J.W. S. Cook
Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity PICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, na=ni, of…
Preprint PublishedB. Chapman R.O. Dendy K.G. McClements S.C. Chapman G.S. Yun S.G. Thatipamula M.H. Kim
Ion cyclotron emission (ICE) is detected during edge localised modes (ELMs) in the KSTAR tokamak at harmonics of the proton cyclotron frequency in the outer plasma edge. The emission typically chirps downward (occasionally upward) during ELM crashes, and is driven by confined 3MeV fusion-born protons that have large drift excursions from the plasma…
Preprint PublishedN.R. Walkden A. Wynn F. Militello B. Lipschultz G. Matthews C.Guillemaut J. Harrison D. Moulton JET Contributors
Statistical analysis of the ion flux to the JET outer-wall is conducted in outer-wall limiter mounted Langmuir probe (OLP) time-series across a wide range of plasma current and line-averaged density during Ohmically heated horizontal target L-mode plasmas. The mean, _, and the standard deviation, _, of the ion-saturation current measured by the OLP…
Preprint PublishedF. Militello T. Farley K. Mukhi N. Walkden J.T. Omotani
A statistical framework was introduced in textit{Militello et al., Nucl. Fusion 56, 104004 (2016)} to correlate the dynamics and statistics of L-mode and inter-ELM plasma filaments with the radial profiles of thermodynamic quantities they generate in the Scrape Off Layer. This paper extends the framework to cases in which the filaments are emitted …
Preprint PublishedZ. Leong J.S. Wróbel S.L. Dudarev R. Goodall I. Todd D. Nguyen-Manh
Multicomponent systems, termed High Entropy Alloys (HEAs), with predominantly single solid solution phases are a current area of focus in alloy development. Although different empirical rules have been introduced to understand phase formation and determine what the dominant phases may be in these systems, experimental investigation has revealed tha…
Preprint PublishedS. Breton F.J. Casson C. Bourdelle C. Angioni E. Belli Y. Camenen J. Citrin X. Garbet Y. Sarazin The JET contributors
Heavy impurities, such as tungsten (W), can exhibit strongly poloidally asymmetric density profiles in rotating or radio frequency heated plasmas. In the metallic environment of JET, the poloidal asymmetry of tungsten enhances its neoclassical transport up to an order of magnitude, so that neoclassical convection is expected to dominate over turbul…
PreprintB. Hnat S. Gadgil A. Kirk F. Militello N. Walkden The MAST Team
Reciprocating Mach probe data is used to estimate the radial wave number of oscillatory zonal flows in Ohmic MAST plasma. An intermittent 10kHz mode is detected in the wavelet decomposition and windowed spectra of plasma potential fluctuations of the MAST tokamak edge plasma. Previously, this mode has been identified as a Geodesic Acoustic Mode (GA…
Preprint Published