Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST

In the Experimental Advanced Superconducting Tokamak (EAST), a transition from electromagnetic to electrostatic turbulence is observed in the pedestal region as plasma density ramps up. This transition is manifested by the suppression of magnetic fluctuations and the presence of broadband electrosta...

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Main Authors: You Li, Ning Yan, Guosheng Xu, Ziqiang Zhou, Ganjun Zhang, Shaocheng Liu, Jilei Hou, Qingquan Yang, Kedong Li, Wenxiang Shi, Guangle Lin, Lin Yu, Yifeng Wang, Xiang Jian, Genfan Ding, Ran Chen, Yuqi Xu, Rui Ding, Jingsen Geng, Wenxue Fu, Qian Long, Panjun Tang, Yufei Zhang, Ang Ti, Haiqing Liu, Liang Wang, Qing Zang, Jinping Qian, the EAST Team
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:Nuclear Fusion
Subjects:
Online Access:https://doi.org/10.1088/1741-4326/adf34b
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author You Li
Ning Yan
Guosheng Xu
Ziqiang Zhou
Ganjun Zhang
Shaocheng Liu
Jilei Hou
Qingquan Yang
Kedong Li
Wenxiang Shi
Guangle Lin
Lin Yu
Yifeng Wang
Xiang Jian
Genfan Ding
Ran Chen
Yuqi Xu
Rui Ding
Jingsen Geng
Wenxue Fu
Qian Long
Panjun Tang
Yufei Zhang
Ang Ti
Haiqing Liu
Liang Wang
Qing Zang
Jinping Qian
the EAST Team
author_facet You Li
Ning Yan
Guosheng Xu
Ziqiang Zhou
Ganjun Zhang
Shaocheng Liu
Jilei Hou
Qingquan Yang
Kedong Li
Wenxiang Shi
Guangle Lin
Lin Yu
Yifeng Wang
Xiang Jian
Genfan Ding
Ran Chen
Yuqi Xu
Rui Ding
Jingsen Geng
Wenxue Fu
Qian Long
Panjun Tang
Yufei Zhang
Ang Ti
Haiqing Liu
Liang Wang
Qing Zang
Jinping Qian
the EAST Team
author_sort You Li
collection DOAJ
description In the Experimental Advanced Superconducting Tokamak (EAST), a transition from electromagnetic to electrostatic turbulence is observed in the pedestal region as plasma density ramps up. This transition is manifested by the suppression of magnetic fluctuations and the presence of broadband electrostatic turbulence. The frequency domain of the electrostatic turbulence is typically beyond 300 kHz. It leads to a rapid build-up of density gradient and a sharp degradation of energy confinement. By reducing the gas puffing rate, a prolonged intermediate transition phase is observed, and the confinement improved with increasing density in this phase. The emergence of broad electrostatic turbulence is associated with the enhanced turbulence control parameter α _t , together with a weaken edge radial electric field. Furthermore, the impact of the turbulence transition to scrape-off layer (SOL) transport is evaluated. Measurements suggested that radial particle flux and intermittent structures are strengthened after the transition. Moreover, the profiles in the far SOL are broaden with increase of α _t . The properties of the magnetic fluctuations are consistent with the nature of the magnetic coherent mode previously observed in EAST, while the broad electrostatic turbulence is proposed to be an ion temperature gradient mode by the Gyrokinetic Electromagnetic Numerical Experiment simulation. It is clarified that the energy confinement degradation in high-density regimes is primarily driven by the broadband turbulence rather than divertor detachment. These findings advance our understanding of high-density H-mode plasmas and provides additional insights into the interplay between edge turbulence and global confinement properties.
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spelling doaj-art-6114022fe4e6455e87981449985151c22025-08-20T02:46:32ZengIOP PublishingNuclear Fusion0029-55152025-01-0165808604610.1088/1741-4326/adf34bStudy on the turbulence transition in the pedestal of high-density H-mode plasmas in EASTYou Li0Ning Yan1https://orcid.org/0000-0002-2536-5853Guosheng Xu2https://orcid.org/0000-0001-8495-8678Ziqiang Zhou3Ganjun Zhang4https://orcid.org/0000-0002-3500-5501Shaocheng Liu5https://orcid.org/0000-0002-7298-0680Jilei Hou6https://orcid.org/0000-0002-7109-5700Qingquan Yang7https://orcid.org/0000-0002-6354-1408Kedong Li8https://orcid.org/0000-0003-0486-7368Wenxiang Shi9https://orcid.org/0009-0005-7223-3748Guangle Lin10Lin Yu11Yifeng Wang12https://orcid.org/0000-0002-0368-9566Xiang Jian13https://orcid.org/0000-0003-3052-1694Genfan Ding14Ran Chen15Yuqi Xu16Rui Ding17https://orcid.org/0000-0003-2880-9736Jingsen Geng18https://orcid.org/0000-0002-0077-4052Wenxue Fu19Qian Long20Panjun Tang21Yufei Zhang22Ang Ti23Haiqing Liu24https://orcid.org/0000-0001-6892-358XLiang Wang25Qing Zang26Jinping Qian27https://orcid.org/0000-0002-2646-6509the EAST TeamHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaUniversity of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaHefei Institutes of Physical Science, Chinese Academy of Sciences , Hefei 230031, ChinaIn the Experimental Advanced Superconducting Tokamak (EAST), a transition from electromagnetic to electrostatic turbulence is observed in the pedestal region as plasma density ramps up. This transition is manifested by the suppression of magnetic fluctuations and the presence of broadband electrostatic turbulence. The frequency domain of the electrostatic turbulence is typically beyond 300 kHz. It leads to a rapid build-up of density gradient and a sharp degradation of energy confinement. By reducing the gas puffing rate, a prolonged intermediate transition phase is observed, and the confinement improved with increasing density in this phase. The emergence of broad electrostatic turbulence is associated with the enhanced turbulence control parameter α _t , together with a weaken edge radial electric field. Furthermore, the impact of the turbulence transition to scrape-off layer (SOL) transport is evaluated. Measurements suggested that radial particle flux and intermittent structures are strengthened after the transition. Moreover, the profiles in the far SOL are broaden with increase of α _t . The properties of the magnetic fluctuations are consistent with the nature of the magnetic coherent mode previously observed in EAST, while the broad electrostatic turbulence is proposed to be an ion temperature gradient mode by the Gyrokinetic Electromagnetic Numerical Experiment simulation. It is clarified that the energy confinement degradation in high-density regimes is primarily driven by the broadband turbulence rather than divertor detachment. These findings advance our understanding of high-density H-mode plasmas and provides additional insights into the interplay between edge turbulence and global confinement properties.https://doi.org/10.1088/1741-4326/adf34bturbulence transitionH-modehigh-densityconfinementpedestalscrape-off layer parameters
spellingShingle You Li
Ning Yan
Guosheng Xu
Ziqiang Zhou
Ganjun Zhang
Shaocheng Liu
Jilei Hou
Qingquan Yang
Kedong Li
Wenxiang Shi
Guangle Lin
Lin Yu
Yifeng Wang
Xiang Jian
Genfan Ding
Ran Chen
Yuqi Xu
Rui Ding
Jingsen Geng
Wenxue Fu
Qian Long
Panjun Tang
Yufei Zhang
Ang Ti
Haiqing Liu
Liang Wang
Qing Zang
Jinping Qian
the EAST Team
Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST
Nuclear Fusion
turbulence transition
H-mode
high-density
confinement
pedestal
scrape-off layer parameters
title Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST
title_full Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST
title_fullStr Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST
title_full_unstemmed Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST
title_short Study on the turbulence transition in the pedestal of high-density H-mode plasmas in EAST
title_sort study on the turbulence transition in the pedestal of high density h mode plasmas in east
topic turbulence transition
H-mode
high-density
confinement
pedestal
scrape-off layer parameters
url https://doi.org/10.1088/1741-4326/adf34b
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