Dynamics and statistics of a self-organized staircase-like electron temperature corrugation in KSTAR plasmas

Turbulent transport near the marginal stability of tokamak plasmas is dominated by non-diffusive avalanche transport events in gyrokinetic simulations. The avalanche transport events are found to interact with self-organized shear flow layers, or the E x B staircase generating a staircase-like pressure corrugation. Various models have been suggested for the relation between the avalanche transport events and the shear flow layers, or the pressure corrugation. While intensive simulation studies have been conducted to advance the understanding of their relation, the experimental researches have been mostly limited to the demonstration of their existence. For example, in KSTAR tokamak plasmas, the co-existence of the avalanche-like electron heat transport events and the staircase-like electron temperature corrugation was confirmed [1]. In this work, further analyses of dynamics and statistics of the self-organized temperature corrugation are provided to understand its evolution and reveal the relation with the avalanche-like events. The avalanche-like events are found to have strong influences on the evolution of the self-organized temperature corrugation.

[1] M. J. Choi et al., Nuclear Fusion 59, 086027 (2019)