Spatial and Temporal Structure of Edge-Localized Modes

Abstract

This Letter provides information on the spatial and temporal structure of periodic eruptions observed in magnetically confined laboratory fusion plasmas, called edge-localized modes (ELMs), and highlights similarities with solar eruptions. Taken together, the observations presented in this Letter provide strong evidence for ELMs being associated with a filamentlike structure. These filaments are extended along a field line, are generated on a 100 micros time scale, erupt from the outboard side, and connect back into the plasma. Such structures are predicted by a theoretical model based on the "ballooning" instability, developed for both solar and tokamak applications.

Convective transport by intermittent blob-filaments: Comparison of theory and experiment

“…While the physics of ELM generation is beyond the scope of this paper, it is important to point out that ELMs produce filaments of plasma that propagate across the far SOL in a manner similar to blobs 19,24,[32][33][34][35][36] (see also Sec. V B 2).…”

Enhanced Understanding of MHD Dynamics & ELM Control Physics via 2D/3D ECE Imaging in KSTAR

“…Edge-localized modes (ELMs) are constantly encountered in the high confinement mode (H-mode) of a tokamak plasma, where the edge pressure gradient is large over a short physical distance near the separatrix, and have been extensively studied in many tokamak devices [3][4][5][6][7][8][9][10] for the last three decades since their first observation in ASDEX [11]. The H-mode was adopted as a standard mode of operation in ITER, yet large ELMs can severely limit the life time of the divertor; thus, understanding and control of this instability became an essential research subject for all diverted tokamaks.…”

Application of optical flow method for imaging diagnostic in JET

“…The wide angle view is appropriate for the study of pellet ablation, large scale instabilities and plasma wall interactions. Since the high confinement mode of operation (H-mode) is the standard operating regime envisaged for ITER, Edge Localised Mode instabilities (ELM) [2] are of particular importance considering the power loads they can induce on the plasma facing components. Recently it has been proven that the view of the fast visible camera is able to provide useful information about ELMs [3].…”

“…9 (first row). In order to obtain a more complete picture about the accuracy of the calculated optical flow, three line profiles have been evaluated for the second image 2 I and its reconstruction ( ) rec I 2 obtained from the first image 1 I and the calculated optical flow. The results are presented also in Fig.…”