-
UKAEA-STEP-PR(25)272023
Electron Bernstein current drive (EBCD) systems are sensitive to plasma and launch conditions, and therefore require large parametric scans to optimise their design. One particular bottleneck in the simulation workflow is quasilinear modelling of current drive efficiency. Linear adjoint models are an attractive alternative, offering a ∼103× spee…
-
UKAEA-CCFE-PR(23)1662023
MAST-Upgrade (MAST-U) is undergoing several enhancements to deliver increased performance and functionality. One such enhancement is the design, development, and implementation of an Electron Bernstein Wave (EBW) Heating and Current Drive (HCD) System. The MAST-U EBW System aims to provide experimental data for model validation, and to provide a…
-
UKAEA-STEP-CP(24)022022
The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program has recently taken the decision to use exclusively microwave-based heating and current drive (HCD) actuators for its reactor concepts. This is based on a detailed assessment considering all viable HCD concepts, covering the grid to plasma efficiency (), physics applica…
-
UKAEA-CCFE-CP(23)472022
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…
-
UKAEA-STEP-CP(23)052022
The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program is now exclusively investigating concepts using microwave-based heating and current drive (HCD) systems. Electron Bernstein Wave (EBW) HCD is a relatively immature technology compared to Electron Cyclotron (EC) HCD but is of interest due to the promise of high current…
-
UKAEA-CCFE-PR(22)862022
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…
-
UKAEA-CCFE-PR(22)852022
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…
-
UKAEA-CCFE-CP(20)912020
The experimental validation of turbulence models is a critical part of developing a predictive understanding of plasma transport. Models based on the non-linear gyrokinetic equations are currently the most well understood and experimentally validated models of turbulence available. However, models of reduced complexity are required in order to mak…
-
CCFE-PR(15)722015
The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D Doppler backscattering (DBS) experiments on MAST. SAMI actively probes the plasma edge using a wide ( 40° vertical and horizontal) and tuneable (10-35.5 GHz) beam. The Doppler backscattered signal is digitised in vector form using an array of eight Vival…
-
CCFE-PR(15)1062015
Recent measurements of microwave and x-ray emission during edge localized mode (ELM) activity in tokamak plasmas provide a fresh perspective on ELM physics. It is evident that electron kinetics, which are not incorporated in standard (fluid) models for the instability that drives ELMs, play a key role in the new observations. These effects should b…
Showing 1 - 10 of 14 UKAEA Paper Results