Table of Content

15 May 2022, Volume 42 Issue s1

Previous Issue    Next Issue

Nuclear Fusion Engineering

Study on high temperature performance of second generation HTS tapes

QIAO Qi, WANG Meng-lin, PEI Ya-tian, LI Dao-zheng, YIN Shao-wu, ZHAO Ling, ZHU Zi-an, NING Fei-peng

2022, 42(s1):  97-101.  DOI: 10.16568/j.0254-6086.2022s1001

Asbtract ( )   PDF (53525KB) ( )  

References | Related Articles | Metrics

The temperature distribution of 20 layers of high temperature superconducting (HTS) tapes is simulated by using finite element software, the simulation results show that both sides of the tape will experience a high temperature of more than 420°C in the process of aluminum coating. The experiments of high temperature heat on ReBCO side, Hastelloy side and both sides of the HTS tapes were carried out under different temperatures and durations, the degradation of critical current of each tape was measured. The results show that high temperature will degrades the ReBCO performance, while the degradation of different tapes is different.

Study of dipole field application with DCT coil

MEI En-ming, , WU Wei, SUN Liang-ting, ZHANG Jing-jing, ZHANG Xiang, , YANG Jing, OU Xian-jin, YOU Wei, YANG Yan-bing, LIANG Yu, ZHAO Li-xia, ZHENG Ya-jun

2022, 42(s1):  102-107.  DOI: 10.16568/j.0254-6086.2022s1002

Asbtract ( )   PDF (19196KB) ( )  

References | Related Articles | Metrics

This paper introduces the electromagnetic design,fabrication and verification of a superconducting dipole with the discrete cosine-theta(DCT) coil of accelerator.

Effects of narrow-stacked wires with different stacking structure on critical current for an HTS cable-in-conduit conductor

SHEN Jian-xia, LI Zhu-yong, XI Dong-min, ZHANG Long, SONG Meng, XIA Ya-jun

2022, 42(s1):  108-113.  DOI: 10.16568/j.0254-6086.2022s1003

Asbtract ( )   PDF (53586KB) ( )  

References | Related Articles | Metrics

In order to improve the structural performance of the superconducting cable, 2mm wide superconducting wires will be used to fabricate narrow-stacked wires, which are embedded in a slotted aluminum tube to prepare a high temperature superconducting (HTS) cable-in-conduit conductor. The effects of different numbers of wires and different twisting pitches on the critical current of the HTS cable-in-conduit conductor are studied. The results show that when the twisting pitch is constant, the larger the number of wires is stacked, the larger the critical current loss rate; when the twisting pitch is 100mm, the superconducting characteristics of the narrow-stacked wires can still be maintained and the critical current does not reduce too much.

Study on the temperature-changing crystal structure of topological material γ-PtBi2

ZHANG Shi-ju, LIU Wei, YANG Meng, LIN Yu, FENG Ya, SHI You-guo, Kenya Shimada, YANG Xiao-feng, Darren C Peets, HE Shao-long

2022, 42(s1):  114-119.  DOI: 10.16568/j.0254-6086.2022s1004

Asbtract ( )   PDF (41990KB) ( )  

References | Related Articles | Metrics

The crystal structure of γ-PtBi₂ at different temperatures was studied by using X-ray diffraction (XRD), angle-resolved photoemission spectroscopy (ARPES) and band-structure calculation methods. The crystal structure at room temperature was determined to be P31m by single crystal XRD. In order to determine the crystal structure of the sample at low temperature, we measured the electronic structure of the sample by ARPES and compared it with the calculated results. The results show that the structure of the sample is consistent with that of P31m, which indicates that the sample still maintains the P31m structure at low temperature. Furthermore, the high temperature XRD study shows that the crystal structure of the sample is still the P31m structure at high temperature.

Optimization of the magnets of a compact high temperature superconducting tokamak based on genetic algorithm

LIANG Han-yu, SHENG Jie

2022, 42(s1):  120-124.  DOI: 10.16568/j.0254-6086.2022s1005

Asbtract ( )   PDF (24821KB) ( )  

References | Related Articles | Metrics

Based on the co-simulation of two-dimensional axisymmetric finite element model of magnetic field and genetic algorithm, the iterative optimization of the magnet parameters of a compact high temperature superconducting (HTS) tokamak was performed. The length of superconducting tapes used is taken as the optimized objective function. Combined with the design indexes of given magnetic flux and background field and the critical current data of HTS tapes under different background field at 50K, the physical parameters and operating current of magnet can be optimized. Finally, the desired results were obtained with a co-simulation of optimization.

Research on the application of deep neural network in automatic targeting technology

XIA Li-qiong, CHEN Bo-lun, WANG Peng, WANG feng

2022, 42(s1):  125-130.  DOI: 10.16568/j.0254-6086.2022s1006

Asbtract ( )   PDF (23192KB) ( )  

References | Related Articles | Metrics

Using the Mask R-CNN to segment the key structure of the CCDs image in inertial confinement fusion (ICF) experimental research, the center of the entrance hole is calculated as the position of the target, and the rationality and feasibility is verified with the simulated image data. Firstly, the program generates batches of simulated images with different structure parameters and different angles as a data set, secondly the operation of noise enhancement and position transformation are made to expand the samples, finally the algorithm model is trained and tested based on the samples, and the center of the entrance hole can be located as the position of the target. The test results show that the accuracy rate and recall rate are above 97%, and the target recognition accuracy is better than 10 pixels.

Applications of AI technique in the diagnostic integrated management and control system in laser facility experiments

CHEN Bo-lun, WANG Peng, XIA Li-qiong, TONG Jie, YANG Chuan, SU Chun-xiao, WANG Feng, YANG Jia-min

2022, 42(s1):  131-136.  DOI: 10.16568/j.0254-6086.2022s1007

Asbtract ( )   PDF (18136KB) ( )  

References | Related Articles | Metrics

A novel integrated computer management and control system is designed with procedure driven framework to manage and control different types of the diagnostics in inertial confinement fusion (ICF) facility. The AI technique is also considered to apply in the control system to implement the autonomous control instead of manual operations in diagnostic setup, system alignment and spatial interference checking. The researches and explores are carried out recently and established on parameters setup of oscilloscope with convolutional neural network (CNN), auto-alignment of diagnostics with Mask-CNN and interference checking and warning with image fusion.

Design of space interference detection and early warning system for inertial confinement fusion experiments

WANG Peng, CHEN Bo-lun, XIA Li-qiong, SU Chun-xiao, WANG Feng

2022, 42(s1):  137-143.  DOI: 10.16568/j.0254-6086.2022s1008

Asbtract ( )   PDF (55669KB) ( )  

References | Related Articles | Metrics

Aiming at the problem of collision risk caused by the simultaneous operation of multiple diagnostic systems in limited space in inertial confinement fusion (ICF) experiments, a space interference detection and early warning system is designed based on the methods of collision target detection and space distance measurement. The applicable conditions and feasibility of different realization methods are analyzed under the specific environment of the vacuum target chamber. The simulation results under the laboratory condition indicate that the depth sensing method based on structured light achieves high spatial distance measurement accuracy, and the distance error is no more than 3cm in the target chamber radius range, which provides a feasible solution for the detection and early warning of target chamber space interference in laser fusion experiments.

Plasma Physics

Discharge simulation and electromagnetic simulation analysis of CFETR snowflake divertor configuration

SONG Qiang, YANG Jin-hong, LU Ye, GUI Teng, WANG Wei-hua

2022, 42(s1):  144-151.  DOI: 10.16568/j.0254-6086.2022s1009

Asbtract ( )   PDF (60004KB) ( )  

References | Related Articles | Metrics

The discharge of CFETR (China Fusion Engineering Test Reactor) is simulated by TSC code, and the discharge configurations of lower single null divertor and snowflake divertor are obtained. The simulation results of the two kinds of divertor discharge configurations in TSC are imported into the finite element analysis software as the source term for electromagnetic simulation calculation. On the established three-dimensional simulation models such as CFETR blanket and divertor, the electromagnetic loads of the blanket and divertor under the discharge potential of the two kinds of divertor configuration are analyzed and compared. The results can provide reference for the physical and engineering design of CFETR.

Experimental studies of edge shear flow and poloidal residual stress in proximity to the density limit of HL-2A tokamak

LONG Ting, Diamond P H, KE Rui, HONG Rong-jie, XU Min, NIE Lin, WANG Zhan-hui, LI Bo, GAO Jin-ming, HL-M Team

2022, 42(s1):  152-157.  DOI: 10.16568/j.0254-6086.2022s1010

Asbtract ( )   PDF (40978KB) ( )  

References | Related Articles | Metrics

Recent experimental results about the edge shear flow and poloidal residual stress near the density limit of HL-2A tokamak are reported in this paper. The studies found that the plasma response passes from adiabatic to hydrodynamic response as the plasma density approaches Greenwald density, therefore the residual stress, which is the non-diffusive item in the turbulent Reynolds stress, is reduced. The plasma intrinsic poloidal torque characterized by the divergence of residual stress decreases drastically. The reduction of turbulent generation of edge poloidal flow leads to the decreased edge E×B poloidal flow shearing rate. These experimental results demonstrate the important role of reduced residual stress in the edge poloidal shear layer collapse in the proximity of tokamak density limit.

Inversion of emissivity and flow velocity measured by coherence imaging spectroscopy diagnostic with Tikhonov method

LI Bing-li, WANG Tian-bo, NIE Lin, LONG Ting, ZHANG Xiao-yi, WANG Hao, ZHANG Xiao-long, JIAO Shao-dong, QING Wan-jun, TIAN Ye, PAN Yuan

2022, 42(s1):  158-163.  DOI: 10.16568/j.0254-6086.2022s1011

Asbtract ( )   PDF (55836KB) ( )  

References | Related Articles | Metrics

Inversion of emissivity measured by coherence imaging spectroscopy diagnostic (CIS) in HL-2A tokamak with Tikhonov algorithm is introduced. After correcting the problems such as visual string deviation caused by camera positioning in HL-2A tokamak,and then the inversion of emissivity and velocity in J-TEXT tokamak is carried out with Tikhonov algorithm.

H mode period recognition in HL-2A tokamak based on convolutional neural network

LIANG Jia-he, LIU Song-fen, WANG Hong-peng, DU Yue, WANG Zhan-hui, CHEN Yi-hang, XU Min, XIA Fan, YANG Zong-yu, ZHONG Wu-lü

2022, 42(s1):  164-169.  DOI: 10.16568/j.0254-6086.2022s1012

Asbtract ( )   PDF (43576KB) ( )  

References | Related Articles | Metrics

A machine learning method has been adopted to train models for H-mode prediction from the HL-2A experimental data. Stored energy and deuterium alpha signals from 206 discharges are selected for training, 15 for validation and 474 for testing. H-mode period of all the data is marked previously. Instances of 2-channel time sequence are generated in the way of time window. Finally, a 21 layers convolutional neural network was developed. It scored 98.17% of accuracy in test set and the recognized H-mode beginning and ending time error were lower than 10ms, which can be applied to the high confinement mode research.

Study on the interaction between high power microwave and atmospheric plasma

WANG Hua-jie, MA Zhe, GONG Shao-bo, ZHOU Jie, JIANG Lai, ZHU Yun-liang, XIAO Chen-yu, XU Min

2022, 42(s1):  170-174.  DOI: 10.16568/j.0254-6086.2022s1013

Asbtract ( )   PDF (78522KB) ( )  

References | Related Articles | Metrics

The evolution of plasma generated by high power microwave continuously penetrating the atmosphere is studied, and the results of black barrier effect of microwave interference on given plasma are obtained.