Pedestal particle balance studies in JET-ILW H-mode plasmas

L. Horvath*, B. Lomanowski, Juuso Karhunen, M. Maslov, P. A. Schneider, J. Simpson, M. Brix, B. Chapman-Oplopoiou, G. Corrigan, L. Frassinetti, M. Groth, K. Lawson, C. F. Maggi, S. Menmuir, R. B. Morales, D. Moulton, O. Myatra, D. Nina, T. Pereira, D. I. RéfyS. Saarelma, M. Vécsei, JET Contributors

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

10 Citations (Scopus)

Abstract

JET-ILW type I ELMy H-modes at 2.5 MA/2.8 T with constant NBI heating (23 MW) and gas fuelling rate were performed, utilising edge localised mode (ELM) pacing by vertical kicks and plasma shaping (triangularity, δ) as tools to disentangle the effects of ELMs, inter-ELM transport and edge stability on the pedestal particle balance. In agreement with previous studies, the pedestal confinement improves with increasing δ, mostly due to a significant increase in pedestal density while the ELM frequency (ƒELM) is decreased. Improved pedestal confinement with increasing δ was observed even when the pedestal MHD stability was degraded artificially by vertical kicks, implying that increased triangularity may favourably affect the inter-ELM pedestal recovery. The workflow developed to quantify the pedestal particle balance uses high time-resolution profile reflectometry to characterise the inter-ELM evolution of the plasma particle content (dN/dt), the NEO drift-kinetic solver to evaluate the neoclassical fluxes and interpretative EDGE2D-EIRENE simulations to estimate the edge particle source. The edge particle source is then constrained by deuterium Balmer-α line intensity measurements in the main chamber, which are, however, strongly affected by reflections from the metal walls. The reflections are accounted for by the CHERAB code taking the divertor emission (the brightest light source in the torus) distribution from imaging spectroscopy measurements as input. Our analysis shows that in the second half of the ELM cycle, the volume-integrated particle source is larger than dN/dt , indicating that transport plays a key role in the inter-ELM pedestal recovery.

Original languageEnglish
Article number044003
Number of pages13
JournalPlasma Physics and Controlled Fusion
Volume65
Issue number4
DOIs
Publication statusPublished - Apr 2023
MoE publication typeA1 Journal article-refereed
Event48th EPS Conference on Plasma Physics: Online - Virtual
Duration: 27 Jun 20221 Jul 2022

Funding

This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200—EUROfusion) and from the EPSRC [Grant Number EP/W006839/1].

Keywords

  • EDGE2D-EIRENE
  • EIRENE
  • fuelling
  • H-mode
  • JET-ILW
  • particle transport
  • pedestal

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