Abstract Details
| status: | file name: | submitted: | by: |
|---|---|---|---|
| approved | sherwood23abs.pdf | 2023-03-25 09:13:03 | Linjin Zheng |
Abstracts
Author: Linjin Zheng
Requested Type: Poster
Submitted: 2023-03-25 09:07:35
Co-authors: M. T. Kotschenreuther, F. L. Waelbroeck, and M. E. Austin
Contact Info:
Institute for Fusion Studies, The University of Te
2515 Speedway
Austin, TX 78712
USA
Abstract Text:
There is renewed interest in the negative triangularity (NT) tokamaks. The TCV and DIII-D experiments found that the low (L) mode discharges in the negative triangularity discharges can reach about the same level beta normal as the H mode confinement [1,2]. Since they are L mode discharges, there are no ELMs. Furthermore, the turbulence level in NT is considerably lower than typical L mode discharges. These observations are found to be consistent with the MHD stability analyses with the AEGIS and DCON codes for DIIID-like equilibria [3,4]. Further investigation of NT configuration in Ref. [3] points out another distinguished and important feature: the NT configuration can generate the rotation transform of magnetic field lines more effectively. It indicates that the NT configuration is potentially preferred for the advanced tokamak scenario with high fraction of bootstrap current and steady-state confinement. In this work, we further exploit this feature. We first use the semi-analytical method to examine how the positive and negative triangularity affects the safety factor profile with the Solovev equilibrium solution. The X point effects are taken into account in this case. The local and nonlocal field line rotation transform will be examined and their effects on the stability will be assessed. The bootstrap current will be introduced afterwards to exploit the possibility of steady state confinement. The comparison with the numerical equilibria with VMEC and ATEQ will also be discussed. This research is supported by Department of Energy Grants DE-FG02-04ER54742.
[1] Camenen Y. et al 2007 Nucl. Fusion 47 510.
[2] Austin M. E. et al. 2019 Phys. Rev. Lett. 122 115001.
[3] Linjin Zheng, M.T. Kotschenreuther, F.L. Waelbroeck, et al. 2018 IAEA-FEC, TH/P5-31.
[4] Linjin Zheng, M.T. Kotschenreuther and F.L. Waelbroeck, 2021 Nucl. Fusion 61 116014.
Comments:
Topics: Plasma equilibrium, stability, and transport