Identification of Plasma Current Center by Neural Network Inference in EAST
Identification of Plasma Current Center by Neural Network Inference in EAST
复制标题
EAST 中神经网络推理识别等离子体电流中心
DOI：
10.1109/tps.2019.2951367
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发表时间：
2020
影响因子：
1.5
通讯作者：
Yong Guo
中科院分区：
文献类型：
--
作者：
Zi-Jian Zhu;Jian-Gang Li;Bing-Jia Xiao;Xueqiao Xu;Yang Fanjie;Yong Guo
为了保证实验先进超导托卡马克（EAST）的高效安全运行，必须准确识别和控制等离子体电流及其中心位置。本文将神经网络用于等离子体电流中心位置的识别。通过基本反向传播神经网络训练的模型可以很好地匹配电磁诊断信号与等离子体电流中心位置之间的关系。利用噪声仿真数据和实验数据对神经网络推理模型进行训练和测试。实验证明，在训练数据中加入0.1%的噪声可以提高推理模型的抗噪声能力。同时使用噪声仿真数据和实际实验数据训练的基础神经网络在输入充足的情况下，具有良好的训练效果；然而，在这两种情况下，当只给出极向场线圈电流作为输入时，性能显著下降。针对这类时间序列问题，引入了包含延迟和反馈结构的动态神经网络，并训练了一个输入更少的改进模型，并对其进行了电流中心推理测试。本文对该模型的一些参数进行了比较和分析。通过适当的神经网络结构，可以建立被控变量（极向场线圈电流）和响应变量（等离子体电流中心）之间的映射关系。
For the efficient and safe operation of experimental advanced superconducting tokamak (EAST), it is necessary to accurately identify and control the plasma current and its central position. In this article, neural network is used to identify the position of the plasma current center. The model trained by the basic back-propagation neural network can well match the relationship between the electromagnetic diagnostic signals and plasma current center positions. Both noisy simulation data and experimental data are applied to train and test the neural network inference model. Adding 0.1% noise to the training data is proven to improve the noise immunity of the inference model. Basic neural networks trained with both noisy simulation data and actual experimental data show good results with sufficient inputs; however, in both cases, the performance degrades significantly when only the poloidal field coil currents are given as inputs. For this kind of time-series problem, the dynamic neural network containing delay and feedback architecture is introduced, and an improved model requiring much fewer inputs is trained and tested for current center inference. Some parameters of this model are compared and analyzed in this article. With suitable neural network architecture, the mapping between the controlled variables (poloidal field coil currents) and response variables (plasma current center) can be well-established.