Plasma and Fusion Research

Volume 17, 2403038 (2022)

Regular Articles

Comparison of MHD Stability between Positive- and Negative-Triangularity Tokamak Plasmas with Internal Transport Barriers
Yusai MASAMOTO, Nobuyuki AIBA1) and Masaru FURUKAWA
Tottori University, 4-101 Minami, Koyama-cho, Tottori-shi, Tottori 680-8552, Japan
National institutes for Quantum and Radiological Science and Technology (QST), Naka, Ibaraki 311-0193, Japan
(Received 10 January 2022 / Accepted 9 March 2022 / Published 13 May 2022)


Ideal magnetohydrodynamics (MHD) stability of tokamak plasmas is compared between positive and negative triangularity cross sections. The bootstrap current is included that is determined from the density and temperature profiles. This is crucial for a DEMO reactor design. The density and temperature profiles are chosen to have internal transport barriers (ITBs), which are necessary if an H-mode edge cannot be expected. The ideal MHD stability is examined in a wide range of the ITB position and the central temperature. We confirmed that ballooning modes are prone to be unstable when the ITB is located near the plasma edge for negative triangularity. Internal kink modes become dominant instability when the ITB is located inner side of the plasma for both positive and negative triangularities. We have succeeded to stabilize both ballooning and internal kink modes by introducing additional currents to control the safety factor profiles in a favorable manner.


DEMO reactor, internal transport barrier, negative triangularity, bootstrap current, ideal MHD stability

DOI: 10.1585/pfr.17.2403038


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