Abstract
Alpha particles with energies on the order of megaelectronvolts will be the main source of plasma heating in future magnetic confinement fusion reactors. Instead of heating fuel ions, most of the energy of alpha particles is transferred to electrons in the plasma. Furthermore, alpha particles can also excite Alfvénic instabilities, which were previously considered to be detrimental to the performance of the fusion device. Here we report improved thermal ion confinement in the presence of megaelectronvolts ions and strong fast ion-driven Alfvénic instabilities in recent experiments on the Joint European Torus. Detailed transport analysis of these experiments reveals turbulence suppression through a complex multi-scale mechanism that generates large-scale zonal flows. This holds promise for more economical operation of fusion reactors with dominant alpha particle heating and ultimately cheaper fusion electricity.
| Original language | English |
|---|---|
| Pages (from-to) | 776-782 |
| Journal | Nature Physics |
| Volume | 18 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 1 Jul 2022 |
| MoE publication type | A1 Journal article-refereed |
Funding
The simulations were performed on the IRENE Joliot-Curie HPC system, in the framework of the PRACE projects IONFAST and AFIETC, led by J. Garcia, and on the CINECA Marconi HPC within the project GENE4EP, led by D. Zarzoso. 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. Part of the work by Ye. O. Kazakov and J.Ongena was also carried out in the framework of projects done for the ITER Scientist Fellow Network (ISFN).
