Abstract Details
Abstracts
Author: Jeronimo Garcia
Requested Type: Pre-Selected Invited
Submitted: 2019-02-06 07:15:56
Co-authors: A. Banon-Navarro, T. Goerler, C. Maggi
Contact Info:
CEA
13108 Saint Paul-Lez-Durance C
Saint Paul-Lez-Durance, 13108
France
Abstract Text:
For more than thirty years, core transport deviations from the expected Gyro-Bohm (GB) scaling with the main ion isotope mass have puzzled the fusion community, leading to the so called isotope effect. A significant effort towards a better understanding has been carried out with the GENE code by performing non-linear gyrokinetic simulations on a large variety of JET plasma conditions in H and D [1] (both in L and H-modes) and ITER extrapolations.
A continuous transition from GB scaling for the ion heat flux to strong deviations has been obtained depending on a variety of effects such as increased collisionality, adiabatic or kinetic electrons or external ExB shearing. An important aspect is the stronger coupling with zonal flows with increasing mass, which is additionally boosted through electromagnetic effects. These elements point out to especial plasma conditions where core isotope effects on transport could be clearly identified, i.e. plasmas at high input power (and beta) and significant torque [2].
Gyrokinetic simulations performed for ITER DT extrapolated high beta plasmas show that isotope effects could be very strong due to the relatively closeness of such plasmas to turbulence threshold. Furthermore, the presence of a significant population of fast ions from the DT reactions lead to even stronger isotope effects, with ion fluxes in DT three times lower than in DD.
Such studies are helping to understand and guide the JET operation, as one of its main goals is the understating of the isotope effect physics. For that purpose, several campaigns in H, D and T are scheduled for the period 2019-2020 and a strong link between experiment and modelling /theory has been established. The final goal is to perform a dedicated and successful DT campaign in 2020 with the aim of addressing ITER DT physics [3].
[1] MAGGI C. F. et al Plasma Phys. Control. Fusion 60 (2018) 014045
[2] GARCIA J et al Nucl. Fusion 57 (2017)
[3] JOFFRIN E. et al submitted to Nuc. Fus
Comments:
Plasma Properties, Equilibrium, Stability, and Transport
Computer Simulation of Plasmas
