Real-time density profile simulations on ASDEX Upgrade and the impact of the edge boundary condition

IF 1.9 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Fusion Engineering and Design Pub Date : 2025-06-16 DOI:10.1016/j.fusengdes.2025.115196

D. Kropackova , F. Pastore , O. Kudlacek , O. Sauter , E. Fable , P. David , EUROfusion Tokamak Exploitation Team , ASDEX Upgrade Team

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引用次数: 0

Abstract

The plasma density is a crucial parameter of tokamak discharge as it impacts the fusion power, stability limits, influences detachment onset and impurities transport. The electron density profile shaping affects the deposition location of the external heating power, thereby playing a role, for instance, in NTM control. Therefore, the real-time estimation of the density profile is essential for high performance tokamak operation.

The real-time density profile reconstruction can be provided by the RAPDENS code (Blanken et al. 2018), which collects density measurements, like interferometers and Thomson scattering (Pastore et al. 2023) and combines them with the solution obtained by its 1.5D particle transport model using the Extended Kalman Filter technique. RAPDENS can be employed in various applications including real-time dynamic state observation, offline reconstruction of the electron density profile with diagnostics not available in real-time, density controller design (owing to its provision of analytical Jacobians), and fast offline density profile simulation.

This contribution presents the improvements made to its predictive model by introducing different boundary conditions, in particular a non-zero, time-varying density at the separatrix. Incorporating the dependence of separatrix density on gas fueling in the non-zero boundary condition improves the quality of the offline simulations used for controller design. Furthermore, this adjustment enhances the versatility of the RAPDENS predictive model, allowing for more efficient density profile reconstruction across a broader range of discharge scenarios and reducing the effort needed to find a suitable combination of tuning parameters to match the density profile at the edge.

A method using a real-time compatible empirical formula (Kallenbach et al. 2018) to determine the separatrix density as a boundary condition for AUG discharges is proposed, and the results of offline RAPDENS simulations are compared with the density profile reconstructed using integrated data analysis (IDA) (Fischer et al. 2010).

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基于ASDEX升级的实时密度分布仿真及边缘边界条件的影响

等离子体密度是托卡马克放电的一个重要参数，它影响聚变功率、稳定极限、分离起始和杂质输运。电子密度分布的成形会影响外部加热功率的沉积位置，从而在NTM控制等方面发挥作用。因此，密度分布的实时估计对托卡马克的高性能运行至关重要。RAPDENS代码（Blanken et al. 2018）可以提供实时密度剖面重建，该代码收集密度测量数据，如干干仪和汤姆森散射（Pastore et al. 2023），并将其与使用扩展卡尔曼滤波技术的1.5D粒子输运模型获得的解相结合。RAPDENS可用于各种应用，包括实时动态观测、无法实时诊断的电子密度分布图离线重建、密度控制器设计（由于其提供解析雅可比矩阵）和快速离线密度分布图模拟。本文通过引入不同的边界条件，特别是分离矩阵处的非零时变密度，对其预测模型进行了改进。在非零边界条件下，结合分离矩阵密度对气体加注的依赖关系，提高了用于控制器设计的离线仿真的质量。此外，这种调整增强了RAPDENS预测模型的通用性，允许在更大范围的放电情况下更有效地重建密度剖面，并减少了寻找合适的调整参数组合以匹配边缘密度剖面所需的工作量。提出了一种使用实时兼容经验公式（Kallenbach et al. 2018）确定分离矩阵密度作为AUG放电边界条件的方法，并将离线RAPDENS模拟结果与使用集成数据分析（IDA）重建的密度剖面进行了比较（Fischer et al. 2010）。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Fusion Engineering and Design 工程技术-核科学技术

CiteScore

3.50

自引率

23.50%

发文量

275

审稿时长

3.8 months

期刊介绍： The journal accepts papers about experiments (both plasma and technology), theory, models, methods, and designs in areas relating to technology, engineering, and applied science aspects of magnetic and inertial fusion energy. Specific areas of interest include: MFE and IFE design studies for experiments and reactors; fusion nuclear technologies and materials, including blankets and shields; analysis of reactor plasmas; plasma heating, fuelling, and vacuum systems; drivers, targets, and special technologies for IFE, controls and diagnostics; fuel cycle analysis and tritium reprocessing and handling; operations and remote maintenance of reactors; safety, decommissioning, and waste management; economic and environmental analysis of components and systems.