Probabilistic theory of the L-H transition and causality

Eun-jin Kim; Abhiram Anand Thiruthummal

doi:10.1088/1361-6587/adab1c

Probabilistic theory of the L-H transition and causality

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Abstract

The low-to-high confinement (L-H) transition is critical for understanding plasma bifurcations and self-organization in high-temperature fusion plasmas. This paper reports a probabilistic theory of the L-H transition, in particular, a probability density function of power threshold Qc for the first time. Specifically, by utilizing a stochastic prey-predator model with energy-conserving zonal flow-turbulence interactions and extensive GPU computing, we investigate the effects of stochastic noises, external perturbations, time-dependent input power ramping, and initial conditions on the power threshold uncertainty. The information geometry theory (information rate, causal information rate) is employed to highlight how statistical properties of turbulence, zonal flows, and mean pressure gradient change over the transition, clarifying self-regulation and causal relations among them.

Original language	English
Article number	025025
Number of pages	11
Journal	Plasma Physics and Controlled Fusion
Volume	67
Issue number	2
DOIs	https://doi.org/10.1088/1361-6587/adab1c
Publication status	Published - 24 Jan 2025
Event	50th European Physical Society Conference on Plasma Physics, EPS - Salamanca, Spain Duration: 8 Jul 2024 → 12 Jul 2024 Conference number: 50 https://epsplasma2024.com

Bibliographical note

© 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Publisher: IOP Publishing

This is the Accepted Manuscript version of an article accepted for publication in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6587/adab1c

Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.

This document is the author’s post-print version, incorporating any revisions agreed during the peer-review process. Some differences between the published version and this version may remain and you are advised to consult the published version if you wish to cite from it.

Funding

This research is supported by Brain Pool Program funded by the Ministry of Science and ICT through the National Research Foundation of Korea (RS-2023-00284119). E K thanks Seoul National University for support and hospitality and M Leconte for useful discussion.

Funders	Funder number
Ministry of Science and ICT
National Research Foundation of Korea	RS-2023-00284119

Keywords

L-H transition
information geometry
self-regulation
stochastic noises
time-dependent probability density function
zonal flows

ASJC Scopus subject areas

Nuclear Energy and Engineering
Condensed Matter Physics

Access to Document

10.1088/1361-6587/adab1c

Kim2025AAMAccepted author manuscript, 13.1 MBLicence: CC BY-NC-ND

Cite this

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Probabilistic theory of the L-H transition and causality

Abstract

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Keywords

ASJC Scopus subject areas

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