Effect of anisotropic thermal transport on tearing mode stability in negative versus positive triangularity plasmas

• Published in: Physics of plasmas 2024-05, Vol.31 (5)
• Main Authors: Yang, Xu, Liu, Yueqiang, Yuan, Jiao, Bai, Xue, Dong, Guanqi, Xia, Guoliang, Zhou, Lina, He, Yuling
• Format: Article
• Language: English
• Subjects: Curvature; Destabilization; Plasma; Plasmas (physics); Stability; Stabilization; Tearing
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/5.0205397

The combined effects of anisotropic thermal transport and the plasma shaping, including negative triangularity, on the n = 1 (n is the toroidal mode number) tearing mode (TM) stability are numerically investigated utilizing the MARS-F code [Liu et al., Phys. Plasmas 7, 3681–3690 (2000)]. While varying the plasma boundary triangularity, the TM stability is found to be dictated by the competing effects of the Shafranov shift induced stabilization and the bad-curvature induced destabilization. The negative triangularity shape increases the Shafranov shift (stabilizing) in the plasma core but also enlarges bad-curvature regions (destabilizing) near the plasma edge, with the net effect being largely destabilizing for the TM as compared to the positive triangularity counter-part. Large negative triangularity however can also lead to more stabilization for the plasma core-localized TM. Anisotropic thermal transport reduces the stabilizing effect on the TM associated with the favorable averaged curvature, resulting in more unstable core-localized TMs in both negative and positive triangularity plasmas. But the opposite effect can also take place for the edge-localized TM in finite-pressure plasmas with negative triangularity.