Open AccessUnderstanding JET-C quiescent phases with edge harmonic magnetohydrodynamic activity and comparison with behaviour under ITER-like wall conditioning
Author(s) -
D. Brunetti,
Christopher Ham,
J. P. Graves,
E. Lazzaro,
S. Nowak,
A. Mariani,
Christer Wahlberg,
W. A. Cooper,
E.R. Solano,
S. Saarelma,
L. Frassinetti,
M. Fontana,
Andreas Kleiner,
Guillermo Bustos Ramirez,
E. Viezzer
Publication year - 2022
Publication title -
plasma physics and controlled fusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.328
H-Index - 111
eISSN - 1361-6587
pISSN - 0741-3335
DOI - 10.1088/1361-6587/ac4d3a
Subject(s) - pedestal , collisionality , jet (fluid) , harmonic , magnetohydrodynamic drive , enhanced data rates for gsm evolution , mechanics , plasma , materials science , tokamak , physics , magnetohydrodynamics , nuclear physics , acoustics , telecommunications , archaeology , computer science , history
An analysis of edge localised mode-free (quiescent) H-mode discharges exhibiting edge harmonic magnetoydrodynamic activity in the JET-carbon wall machine is presented. It is observed that the otherwise quiescent pulses with multiple- n harmonic oscillations are sustained until a threshold in pedestal electron density and collisionality is crossed. The macroscopic pedestal parameters associated with the quiescent phase are compared with those of a database of JET-ELMy discharges with both carbon and ITER-like wall (ILW). This comparison provides the identification of the existence regions in the relevant pedestal and global plasma parameters for edge harmonic oscillations (EHOs) in JET plasmas. Although the ELMy database scans pedestal collisionality and β values typical of ET-carbon quiescent operation, shaping and current are not simultaneously compatible with EHO existence. Nevertheless, ILW operation with JET-carbon quiescent-like parameters could in principle be achieved, and improved pedestal performance could be observed in more recent JET-ILW pulses.