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Title: Assessment of Edge Turbulence and Convective Transport through Velocity Field Analysis

Over the course of this grant period, we have conducted three major studies, each of which has resulted in a primary publication (described below): First, we investigated the flow and shear behavior of the edge plasma and scrape-off layer (SOL) in NSTX using the GPI diagnostic. Calculation of local, time resolved velocity maps using the hybrid optical flow and pattern matching velocimetry code enabled analysis of turbulent flow and shear behavior in these plasmas. Second, we used GPI measurements made during RF heated H-mode operation, to identify intermittent periodic edge intensity fluctuations which precede ELMs and ELM-induced back transitions from H-mode to Lmode. These edge oscillations have a well-defined mode structure and are visible up to 100-200 μs preceding the ELM events. Finally, we performed an in-depth investigation between the fluctuation measurements made by the GPI and BES diagnostics on NSTX.
Authors:
 [1]
  1. Univ. of Colorado, Boulder, CO (United States). Center for Integrated Plasma Studies
Publication Date:
OSTI Identifier:
1176964
Report Number(s):
DOE-Colorado--11111
DOE Contract Number:
FG02-08ER54995
Resource Type:
Technical Report
Research Org:
Univ. of Colorado, Boulder, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY Plasma; Turbulence; Imaging