Abstract Details
Abstracts
Author: Michael R. Hardman
Requested Type: Pre-Selected Invited
Submitted: 2019-02-20 06:31:44
Co-authors: M.Barnes, C.M.Roach, and F.I.Parra
Contact Info:
University of Oxford
Clarendon Laboratory, Parks R
Oxford, OX1 3PU, Note my po 00000
UK
Abstract Text:
Turbulence in magnetic confinement fusion devices has a multi-scale character, due to the smallness of the electron-to-ion mass ratio, and the distinct micro-instabilities driven at the scales of the electron and ion gyroradii. Multi-scale gyrokinetic simulations show the effect of cross-scale interactions [1,2], which can significantly change the character and saturated level of the turbulent transport in multi-scale simulations compared to single scale simulations. We obtain a model of multi-scale turbulence by expanding the gyrokinetic equation in mass ratio [3]. We find gyrokinetic equations describing coupled, scale-separated ion and electron scale turbulence. The cross-scale terms in our equations provide scale-separated mechanisms for cross-scale interactions seen in multi-scale simulations. Our model is solved in a system of coupled flux tubes, making simulations of multi-scale turbulence possible at reduced cost. We present a study exploring the effect of ion scale turbulence on electron scale physics using the flux tube code GS2. We find that electron scale turbulence can be strongly modified in the presence of both weakly and strongly driven ion scale turbulence. We discuss the dominant interaction mechanisms in our model.
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No 633053 and from the RCUK Energy Programme [grant number EP/P012450/1]. The views and opinions expressed herein do not necessarily reflect those of the European Commission. The authors acknowledge EUROfusion, the EUROfusion High Performance Computer (Marconi-Fusion), and the use of ARCHER through the Plasma HEC Consortium EPSRC grant number EP/L000237/1 under the projects e281-gs2.
1. Howard et al. Nucl. Fusion 56:014004 (2016)
2. Maeyama et al. Nucl. Fusion 57:066036 (2017)
3. Hardman et al. ArXiv 1901.07062 (2019)
Comments:
As this work is funded by EUROfusion, I cannot agree to any transfer of copyright -- if an agreement is required it must be the "EUROfusion Permission to Publish Agreement".
