MHD simulations of magnetic island stabilization
Event details
| Date | 28.10.2016 |
| Hour | 10:30 › 11:30 |
| Speaker |
Dr. Olivier Février CEA-Cadarache, F |
| Location |
PPB 019
|
| Category | Conferences - Seminars |
The confinement degradation of tokamak plasma by magnetic islands motivates to better understand their possible suppression using Electron Cyclotron Current Drive (ECCD). In this seminar, we present nonlinear simulations of this process with the toroidal MHD code XTOR, which has been extended to incorporate in Ohm's law a source term modelling the RF driven current resulting from the interaction of the RF waves with the plasma. The implementation has been validated, in a single fluid MHD model, against analytical theory regarding the stabilization efficiency, while the effect of the 3D spatial localization of the RF source appears to impact the island dynamics when the plasma is nearly static. We then move on to the topic of control strategies, and evaluate the efficiency of several control methods. A basic control system has been implemented in XTOR, allowing testing advanced strategies that require feedback on island position or phase. We focus in particular on the robustness of the control strategies towards the uncertainties that apply on the control and ECCD systems, such as the risk of misalignment of the current deposition or the possible inability to generate narrow current deposition. We show that the proper choice of stabilization strategy allows alleviating such experimental uncertainties. Finally, we present preliminary results on current work on the modeling of sawtooth control with ECCD. Depending on the radial location of a current deposition, we observe that the shape and period of sawtooth are altered, and the results obtained with XTOR appears to be in qualitative agreement with experimental results.
Practical information
- Informed public
- Free
Organizer
- Prof. P. Ricci
Contact
- Prof. P. Ricci