P. Ollus S. Allan J.R. Harrison A. Jackson T. Kurki-Suonio K.G. McClements C.A. Michael D. Moulton B.S. Patel M. Robson A. Snicker J. Varje C. Vincent the MAST-U team the EUROfusion WPTE team
Predictions of the impact of charge-exchange (CX) reactions on beam ions in the MAST Upgrade spherical tokamak have been compared to measurements carried out with a fission chamber (neutron fluxes) and a Fast Ion Deuterium-Alpha (FIDA) diagnostic. A simple model was developed to reconstruct the outer-midplane neutral density based on Thomson sca…
PreprintL. Howlett I. Cziegler S. Freethy H. Meyer
A comprehensive L-H power threshold study of MAST data is presented, with a detailed categorisation of transition and intermediate behaviour and a comparison of the results to scaling laws. Preliminary studies into the ion and electron heat flux for transitions at different densities are introduced. The first results of an L-H transition study o…
PreprintJ.F. Rivero-Rodriguez S. Sharapov K. McClements M. Garcia-Muñoz N. Crocker M. Dreval D. Dunai N. Fil M. Fitzgerald J. Galdon-Quiroga C. Michael D. Ryan L. Velarde the MAST-U Team
Due to their relatively higher Vbeam/VAlvén ratio, spherical tokamaks are ideal to investigate high-frequency modes such as Compressional Alfvén Eigenmodes (CAEs) and Global Alfvén Eigenmodes (GAEs), and so they have been previously studied in MAST [1, 2]. Besides, the recently installed scintillator-based Fast-Ion Loss …
PreprintR. Scannell the MAST Upgrade EUROfusion Tokamak Exploitation Teams
MAST Upgrade (MAST-U) is a new low aspect ratio device (R/a = 0.85/0.65 ~ 1.3) based on the MAST tokamak that started plasma operations in October 2020. It has substantial new capabilities compared with the original MAST device, with 19 new poloidal field coils (14 of which are within the vacuum vessel) and new, closed, up-down symmetric diverto…
PreprintV.H. Hall-Chen F.I. Parra J.C. Hillesheim J. Ruiz Ruiz N.A. Crocker P. Shi H.S. Chu S.J. Freethy L.A. Kogan W.A. Peebles Q.T. Pratt T.L. Rhodes K. Ronald R. Scannell D.C. Speirs S. Storment J. Trisno
Doppler reflectometry, or the Doppler backscattering (DBS) diagnostic, enables the measurement of turbulent density fluctuations of intermediate length scales, typically $10 gtrsim k_perp rho_i gtrsim 1$; here $k_perp$ is the turbulence’s wavenumber and $rho_i$ is the ion gyroradius. The backscattered power is proportional to the power of the tur…
PreprintL. Howlett I. Cziegler S.J. Freethy H. Meyer
Spherical tokamaks are known to differ from conventional tokamaks in a number of physics areas, but our understanding is limited by a comparative lack of experimental data. A comprehensive study of the density dependence of the H-mode power threshold PLH on the Mega-Amp Spherical Tokamak (MAST) is presented, mapping out the low-density a…
PreprintV.H. Hall-Chen J. Damba F.I. Parra Q.T. Pratt C.A. Michael S. Peng T.L. Rhodes N.A. Crocker J.C. Hillesheim R. Hong S. Ni W.A. Peebles C.E. Png J. Ruiz Ruiz
We use the beam model of Doppler backscattering (DBS), which was previously derived from beam tracing and the reciprocity theorem, to shed light on mismatch attenuation. This attenuation of the backscattered signal occurs when the wavevector of the probe beam’s electric field is not in the plane perpendicular to the magnetic field. Correcting …
PublishedJ. Lovell M. L. Reinke A. R. Field B. A. Lomanowski the MAST Upgrade team
The MAST Upgrade tokamak has a suite of foil bolometers to measure the total radiated power from the plasma. Arrays of bolometers provide coverage of the main chamber and lower divertor radiation. Data is digitised and processe…
Preprint PurchaseNick Walkden Fabio Riva James Harrison Fulvio Militello Tom Farley John Omotani
Fusion power plant designs based on magnetic confinement, such as the tokamak design, offer a promising route to sustainable fusion power but require robust exhaust solutions capable of tolerating intense heat and particle fluxes from the plasma to material surfaces. Turbulent plasma transport in the divertor volume – the region where the plasma-…
Preprint PublishedC. Vincent S. Allan G. Naylor R. Stephen S. Bray A. Thornton A. Kirk
Neutron flux measurements are important in fusion devices for both safety requirements and physics studies. A newsystem has been built for the Mega Amp Spherical Tokamak Upgrade (MAST Upgrade) that provides neutron count,DC and Campbell mode measurements for a 1μsperiod at 1 MHz. The acquisition system uses a Red Pitaya board tosample current from…
Preprint Published