Dominant two-fluid magnetohydrodynamic instabilities in CFETR upgrade phase-I scenario in presence of perfect conducting wall
Abstract
The dominant two-fluid magnetohydrodynamic (MHD) stabilities of China Fusion Engineering Test Reactor upgrade phase-I baseline equilibria in presence of perfect conducting wall have been evaluated using the initial value code NIMROD. Our MHD simulations show that for equilibrium with qaxis < 1, high-n edge localized modes are slightly stabilized by toroidal shear flow, and n = 1 mode is found to be unstable in the core region with the characteristic of sawtooth instability. For qaxis > 2 equilibrium, all modes are found to be unstable but edge localized both in single-fluid and two-fluid MHD models. Specifically for n ≤ 13 modes, the two-fluid MHD model gives a slightly higher growth rate than the single-fluid MHD model, while for n > 13 modes, this trend becomes the opposite, which means the two-fluid MHD model is needed for high-n mode analysis. In addition, n = 1-10 modes are found to be more unstable with increasing wall position and eventually their growth rates approach values in the no-wall limit.
- Publication:
-
Plasma Physics and Controlled Fusion
- Pub Date:
- April 2019
- DOI:
- 10.1088/1361-6587/ab0090
- Bibcode:
- 2019PPCF...61d5009C
- Keywords:
-
- CFETR;
- macroscopic stability;
- two-fluid MHD;
- NIMROD;
- conducting wall