Two-Dimensional Visualization of Growth and Burst of the Edge-Localized Filaments in KSTAR $H$-Mode Plasmas

Two-Dimensional Visualization of Growth and Burst of the Edge-Localized Filaments in KSTAR $H$ -Mode Plasmas

G. S. Yun, W. Lee, M. J. Choi, J. Lee, H. K. Park, B. Tobias, C. W. Domier, N. C. Luhmann, Jr., A. J. H. Donné, and J. H. Lee (KSTAR Team)

Phys. Rev. Lett. 107, 045004 – Published 22 July 2011

Abstract

The filamentary nature and dynamics of edge-localized modes (ELMs) in the KSTAR high-confinement mode plasmas have been visualized in 2D via electron cyclotron emission imaging. The ELM filaments rotating with a net poloidal velocity are observed to evolve in three distinctive stages: initial linear growth, interim quasisteady state, and final crash. The crash is initiated by a narrow fingerlike perturbation growing radially from a poloidally elongated filament. The filament bursts through this finger, leading to fast and collective heat convection from the edge region into the scrape-off layer, i.e., ELM crash.