M. Giacomin D. Dickinson D. Kennedy B. Patel C. M. Roach
Linear and nonlinear gyrokinetic simulations are performed in experimentally relevant scenarios built from a MAST case where a microtearing mode instability dominates at ion Larmor radius scale. This collisional microtearing mode instability appears only when a vel…
PreprintS. Elmore A. J. Thornton R. Scannell A. Kirk the MAST Team
Understanding the plasma parameters that affect the scrape off layer (SOL) width is a key issue for future tokamaks as the power entering the SOL (of order 100 MW [1] in ITER) and the SOL width (of order millimetres [2]) determine the heat flux to the divertor surfaces. The Eich scaling [2] can be used to characterise the divertor heat flux prof…
Preprint PublishedFabio Federici Matthew L. Reinke Bruce Lipschultz Andrew J. Thornton James R. Harrison Jack J. Lovell Peter Ryan Matthias Bernert Hendrik F. Meyer the MAST Upgrade team
A prototype infrared video bolometer (IRVB) was succesfully deployed in MAST-U, the first deployment of such a diagnostic in spherical tokamaks. The IRVB was designed to study the radiation around the x-point and has the potential to return emissivity profiles of unprecedented spatial resolution. The system was fully characterised prior installatio…
Preprint PurchaseM Cecconello
Spherical tokamaks are key for the successful design of operating scenarios of future fusion reactors in the areas of divertor physics, neutral beam current drive and fast ion physics. MAST Upgrade, which has successfully concluded its first experimental campaign, was specifically designed to address the role of the radial gradient of the fast ion…
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 for…
PreprintJ. 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 Purchase