Abstract
A model for simulating charge exchange (CX) of fast ions with background atoms in magnetically confined fusion plasmas has been implemented in the ASCOT orbit-following code. The model was verified by comparing simulated reaction mean free paths to analytical values across a range of fusion-relevant parameters. ASCOT was used to simulate beam ions slowing down in the presence of CX reactions in a MAST-U target scenario. ASCOT predicts the CX-induced loss of beam power to be 22%, which agrees to within 15% with the TRANSP prediction. Due to CX, plasma heating and current drive by beam ions are strongly reduced towards the edge. However, an overall lower but noticeable increase of up to 20% in current drive is predicted closer to the core. The simulated deposition of fast CX atoms on the wall is concentrated around the outer midplane, with estimated peak power loads of 70-80 kW m-2 on the central poloidal field coils (P5) and the vacuum vessel wall between them. This analysis demonstrates that ASCOT can be used to simulate fast ions in fusion plasmas where CX reactions play a significant role, e.g. in spherical tokamaks and stellarators.
| Original language | English |
|---|---|
| Article number | 035014 |
| Journal | Plasma Physics and Controlled Fusion |
| Volume | 64 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Mar 2022 |
| MoE publication type | A1 Journal article-refereed |
Funding
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 Grant No. EP/T012250/1. This work was partially funded by the Academy of Finland Project Nos. 328874 and 324759.
Keywords
- ASCOT
- beam ions
- charge exchange
- fast ions
- MAST-U
