Real-time equilibrium reconstruction by neural network based on HL-3 tokamak

Fuente: arXiv
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Main Authors: Zheng, Guohui, Liu, Songfen, Yang, Zongyu, Ma, Rui, Gong, Xinwen, Wang, Ao, Wang, Shuo, Zhong, Wulyu
Format: Preprint
Published: 2024
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author Zheng, Guohui
Liu, Songfen
Yang, Zongyu
Ma, Rui
Gong, Xinwen
Wang, Ao
Wang, Shuo
Zhong, Wulyu
author_facet Zheng, Guohui
Liu, Songfen
Yang, Zongyu
Ma, Rui
Gong, Xinwen
Wang, Ao
Wang, Shuo
Zhong, Wulyu
contents A neural network model, EFITNN, has been developed capable of real-time magnetic equilibrium reconstruction based on HL-3 tokamak magnetic measurement signals. The model processes inputs from 68 channels of magnetic measurement data gathered from 1159 HL-3 experimental discharges, including plasma current, loop voltage, and the poloidal magnetic fields measured by equilibrium probes. The outputs of the model feature eight key plasma parameters, alongside high-resolution ($129\times129$) reconstructions of the toroidal current density $J_{\text P}$ and poloidal magnetic flux profiles $Ψ_{rz}$. Moreover, the network's architecture employs a multi-task learning structure, which enables the sharing of weights and mutual correction among different outputs, and lead to increase the model's accuracy by up to 32%. The performance of EFITNN demonstrates remarkable consistency with the offline EFIT, achieving average $R^2 = 0.941, 0.997$ and $0.959$ for eight plasma parameters, $Ψ_{rz}$ and $J_{\text P}$, respectively. The model's robust generalization capabilities are particularly evident in its successful predictions of quasi-snowflake (QSF) divertor configurations and its adept handling of data from shot numbers or plasma current intervals not previously encountered during training. Compared to numerical methods, EFITNN significantly enhances computational efficiency with average computation time ranging from 0.08ms to 0.45ms, indicating its potential utility in real-time isoflux control and plasma profile management.
format Preprint
id arxiv_https___arxiv_org_abs_2405_11221
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Real-time equilibrium reconstruction by neural network based on HL-3 tokamak
Zheng, Guohui
Liu, Songfen
Yang, Zongyu
Ma, Rui
Gong, Xinwen
Wang, Ao
Wang, Shuo
Zhong, Wulyu
Plasma Physics
A neural network model, EFITNN, has been developed capable of real-time magnetic equilibrium reconstruction based on HL-3 tokamak magnetic measurement signals. The model processes inputs from 68 channels of magnetic measurement data gathered from 1159 HL-3 experimental discharges, including plasma current, loop voltage, and the poloidal magnetic fields measured by equilibrium probes. The outputs of the model feature eight key plasma parameters, alongside high-resolution ($129\times129$) reconstructions of the toroidal current density $J_{\text P}$ and poloidal magnetic flux profiles $Ψ_{rz}$. Moreover, the network's architecture employs a multi-task learning structure, which enables the sharing of weights and mutual correction among different outputs, and lead to increase the model's accuracy by up to 32%. The performance of EFITNN demonstrates remarkable consistency with the offline EFIT, achieving average $R^2 = 0.941, 0.997$ and $0.959$ for eight plasma parameters, $Ψ_{rz}$ and $J_{\text P}$, respectively. The model's robust generalization capabilities are particularly evident in its successful predictions of quasi-snowflake (QSF) divertor configurations and its adept handling of data from shot numbers or plasma current intervals not previously encountered during training. Compared to numerical methods, EFITNN significantly enhances computational efficiency with average computation time ranging from 0.08ms to 0.45ms, indicating its potential utility in real-time isoflux control and plasma profile management.
title Real-time equilibrium reconstruction by neural network based on HL-3 tokamak
topic Plasma Physics
url https://arxiv.org/abs/2405.11221