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Continuous observation of filaments from the confined region to the far scrape-off layer

Authors :
E. Wolfrum
M. Faitsch
M. Griener
R. Fischer
G. F. Harrer
G. Fuchert
D. Wendler
U. Stroth
P. Manz
G. Birkenmeier
L. Gil
ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society
EUROfusion MST1 Team
Source :
Nuclear Materials and Energy, Nuclear Materials and Energy, Vol 25, Iss, Pp 100854-(2020)
Publication Year :
2020

Abstract

The thermal helium beam diagnostic at ASDEX Upgrade can access the whole plasma edge region simultaneously with a high spatiotemporal resolution. Manifold dynamics of plasma edge transport is observed for different plasma confinement regimes, comprising L- and H-mode scenarios with type-I and small ELMs as well as ELM free EDA regimes. The measurements show that the plasma dynamics in the confined region close to the separatrix is often dominated by regular high frequency modes (10–100 kHz), whereas filaments with an intermittent occurrence rate of 0.1–2 kHz dominate in particular the far scrape-off layer (SOL). The comparison among different regimes shows a similar filamentary activity between L-mode and inter-ELM H-mode phases. An increased filamentary activity in H-mode, however, is found for rising densities n ∕ n GW . This is the case for the regime of quasi continuous exhaust (QCE) with three times higher filament velocities compared to a clean inter-ELM H-mode.

Details

Language :
English
Database :
OpenAIRE
Journal :
Nuclear Materials and Energy, Nuclear Materials and Energy, Vol 25, Iss, Pp 100854-(2020)
Accession number :
edsair.doi.dedup.....ecc87b9f017d6e6dd1d903875459749a