First ion temperature measurements in the MAST-U divertor via Retarding Field Energy Analyzer

Damizia, Y ORCID: 0009-0006-0612-6300, Elmore, S, Ryan, P, Allan, S, Federici, F ORCID: 0000-0002-9354-7309, Osborne, N and Bradley, JW ORCID: 0000-0002-8833-0180 (2025) First ion temperature measurements in the MAST-U divertor via Retarding Field Energy Analyzer Nuclear Materials and Energy, 43. p. 101912. ISSN 2352-1791, 2352-1791

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Abstract

This study presents the first ion temperature (T<inf>i</inf>) measurements from the MAST-U divertor using a Retarding Field Energy Analyzer (RFEA). Embedded within the flat tile of the closed divertor chamber, the RFEA captures T<inf>i</inf> profiles across various plasma scenarios, including transitions to the Super-X configuration. Measurements were conducted under steady-state and transient plasma conditions characterized by a plasma current (I<inf>p</inf>) of 750 kA, electron density (n<inf>e</inf>) between 2.2×10¹⁹ and 4.4×10¹⁹m⁻³, and Neutral Beam Injection (NBI) power ranging from 3.0 MW to 3.2 MW. The ion temperatures, peaking at approximately 17 eV in steady state, were compared with electron temperatures (T<inf>e</inf>) obtained from Langmuir probes (LP) at identical radial positions. Preliminary findings reveal a T<inf>i</inf>/T<inf>e</inf> ratio ranging from 1 to 2.2. Additionally, high temporal resolution measurements (100μs) captured the dynamics of Edge Localized Modes (ELMs), showing T<inf>i</inf> peaks at 16 ±1.8 eV during ELM events, nearly three times higher than inter-ELM temperatures.

Item Type:	Article
Uncontrolled Keywords:	5106 Nuclear and Plasma Physics, 51 Physical Sciences
Divisions:	Faculty of Science & Engineering Faculty of Science & Engineering > School of Electrical Engineering, Electronics and Computer Science
Depositing User:	Symplectic Admin
Date Deposited:	14 Mar 2025 11:23
Last Modified:	23 Jan 2026 18:27
DOI:	10.1016/j.nme.2025.101912
Open Access URL:	https://doi.org/10.1016/j.nme.2025.101912
Related Websites:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3190819
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