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Reference Number EP/R034737/1
Title Multiscale turbulent dynamics of tokamak plasmas
Status Started
Energy Categories NUCLEAR FISSION and FUSION(Nuclear Fusion) 100%;
Research Types Basic and strategic applied research 100%
Science and Technology Fields PHYSICAL SCIENCES AND MATHEMATICS (Physics) 100%
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Professor H Wilson
No email address given
University of York
Award Type Standard
Funding Source EPSRC
Start Date 01 October 2018
End Date 31 March 2024
Duration 66 months
Total Grant Value £4,349,473
Industrial Sectors Energy
Region Yorkshire & Humberside
Programme NC : Physical Sciences
Investigators Principal Investigator Professor H Wilson , Physics, University of York (99.990%)
  Other Investigator Mr F I Parra Diaz , Oxford Physics, University of Oxford (0.001%)
Dr A Schekochihin , Oxford Physics, University of Oxford (0.001%)
Dr M Barnes , Oxford Physics, University of Oxford (0.001%)
Dr BF McMillan , Physics, University of Warwick (0.001%)
Dr RGL Vann , Physics, University of York (0.001%)
Dr D Dickinson , Physics, University of York (0.001%)
Dr I Cziegler , Physics, University of York (0.001%)
Professor ADR Phelps , Physics, University of Strathclyde (0.001%)
Dr K Ronald , Physics, University of Strathclyde (0.001%)
Professor S (Steven ) Cowley , Culham Centre for Fusion Energy, EURATOM/CCFE (0.001%)
  Industrial Collaborator Project Contact , United Kingdom Atomic Energy Authority (UKAEA) (0.000%)
Web Site
Abstract Plasma turbulence underpins a wide range of phenomena, including the formation of stars and galaxies; the properties of the solar wind, and - the focus of this programme - the confinement of plasmas in tokamaks. It is complicated by feedback mechanisms that couple space and time scales spanning several orders of magnitude. The full problem is extremely challenging, and so to make progress for real world applications we must develop reduced models that capture the essential physics. The goal of our proposed programme is to address this by advancing our understanding of these multi-scale interactions at a fundamental science level. This will be achieved by coupling analytic theory, advanced computation and experimental capabilities, including the newly upgraded MAST-U tokamak.Plasma turbulence is complicated by the fact that there are at least two types of interacting "fluids" - electrons and ions - and these are charged. Fluctuations in density therefore drive charge separation and hence fluctuations in the electrostatic field, while fluctuations in velocity drive currents and hence fluctuations in the magnetic field. These fields then couple the relative motions of the electron and ion "fluids". The situation is further complicated by the rich variety of waves that a magnetised plasma supports, and the resonances that exist when the phase velocity of a wave matches the particle velocity. To properly treat these resonances requires knowledge of the particle velocity distribution; this, in turn, requires either a kinetic or an advanced fluid approach - a daunting task.Turbulence, typically at the millimetre-centimetre scale in tokamaks, interacts in a complex way with the global equilibrium profiles (density, temperature and flow gradients, for example), which are on the metre-scale. To quantify the complex, multi-scale feedback mechanisms between tokamak plasma turbulence and profiles, and so provide a predictive capability for the quasi-steady final states, we will address and integrate a number of topics. We will first learn how mean flows interact with electrostatic turbulence (ie neglecting fluctuations in the magnetic field), requiring coupling between fluctuations with characteristic scales ranging from the electron Larmor radius (sub-mm) through to the ion Larmor radius (few mm) and beyond (cm), to the system length scale of the profiles (m). Our new theory and simulations will inform experiments on MAST-U, exploiting two diagnostic instruments already planned for the device (beam emission spectroscopy and doppler back-scattering). It is likely there will be gaps in the wavelength range that these instruments can measure, so we anticipate a need to develop and install a new microwave imaging system. This will be designed using knowledge gained from the early phase of the programme, and deployed for further experiments towards the end.Understanding of electromagnetic turbulence is less developed and new theoretical models will be required. Building on the knowledge gained from the electrostatic turbulence, we will seek to again understand the multi-scale interactions and feedbacks, including flows. However, now the situation is more complicated as electromagnetic turbulence can drive large scale currents, modifying the magnetic field which confines the plasma, and coupling into large scale electromagnetic modes.A key motivation is to optimise tokamak plasmas for fusion performance, and this requires us to understand the impact of fast particles. These can drive turbulence directly through the instabilities they excite, or influence the turbulence driven by the thermal particles. Our simulations will assess the impact of the fast particles created by the neutral beam heating systems on MAST-U, and also the impact of energetic alpha particles from fusion reactions on future devices like ITER, as well as experiments planned on JET with the deuterium-tritium mix fusion fuel.
Publications (none)
Final Report (none)
Added to Database 28/01/19