Time-dependent probability density function analysis of H-mode transitions

Hiro J. Farre-Kaga, Yasmin Andrew, Jamie Dunsmore, Eun-jin Kim, Terry L. Rhodes, Lothar Schmitz, Zheng Yan

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2 Citations (Scopus)
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The first application of time-dependent probability density function (PDF) analysis to the L-H transition in fusion plasmas is presented. PDFs are constructed using Doppler Backscattering data of perpendicular fluctuation velocity, , and turbulence from the edge region of the DIII-D tokamak. These raw time-series data are sliced into millisecond-long sliding time-windows to create PDFs. During the transition, the PDFs develop strong right tails, indicative of turbulence-suppressing localised flows in the plasma edge; such features and other subtle behaviours are explored using novel information geometry techniques. This letter examines the applicability of these techniques to predict L-H transitions and investigate predator-prey self-regulation theories between turbulence and perpendicular velocity.
Original languageEnglish
Article number64001
Number of pages8
JournalEurophysics Letters
Issue number6
Publication statusPublished - 7 Jun 2023

Bibliographical note

Copyright c 2023 The author(s)
Published by the EPLA under the terms of the Creative Commons Attribution 4.0 International License
(CC BY). Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI:10.1209/0295-5075/acd955


The authors would like to acknowledge the DIII-D team, and give special thanks to Quinn Pratt and Kathreen Thome, for their assistance, support and illuminating discussions. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Award(s) DE-FC02-04ER54698, DE-SC0019352, DE-SC-0020287, and DE-FG02-08ER54999. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclose or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily state of reflect those of the United States Government or any agency thereof.


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