In this work, we investigate the landscape of quasi-isodynamic stellarators using the near-axis expansion of the magnetic field. Building on recent theoretical developments, we construct a database of more than 800,000 stable, approximately quasi-isodynamic vacuum magnetic configurations. These configurations span a range of field period numbers and other geometric control parameters, including the magnetic axis shape and plasma elongation. To evaluate each configuration, we use a broad set of measures, including effective ripple, sensitivity of the Shafranov shift to changes in plasma beta, the prevalence of maximum-J trapped particles, and the Rosenbluth-Hinton residual, among others. This enables an exhaustive, thorough and quantitative characterization of the database. Statistical analysis and modern machine learning techniques are then employed to find correlations, and identify key descriptors and heuristics to help understand tendencies that govern the behaviour of numerical optimization. The database provides baseline configurations for further studies, and to serve as tailored initial conditions for optimization. With this work we initiate a long term program to complete a systematic exploration of quasi-isodynamic stellarator design space.
Direct construction of stellarator-symmetric quasi-isodynamic magnetic configurations
针对准等动力学、N场周期、仿星器对称、单阱磁场平衡的情况，发展了Garren & Boozer（1991）、Plunk et al.（2019）和Plunk et al.（2021）中描述的MHD平衡方程的一阶近轴展开形式。的磁轴形状的重要性进行了研究，我们得出结论，控制的曲率和扭转是至关重要的，以获得具有有限的纵横比和低有效纹波的全能配置，特别是对于一个较高的字段周期数。基于此，本文提出了一种构造具有良好曲率和挠率的轴类的方法。提出了解决方案，包括一个三场周期的配置构造在纵横比为A=20，与e=3.2的最大延伸率和有效波纹小于1%，这表明，高延伸率不是一个必要的功能QI仿星器。
On shear Alfvén wave-induced energetic ion transport in optimized stellarators
Columbia University（哥伦比亚大学）；Max Planck Institute for Plasma Physics（马克斯·普朗克等离子体物理研究所）；Cornell University（康奈尔大学）；Oak Ridge National Laboratory（橡树岭国家实验室）
Characterizing Flux-Surface Shapes in Tokamaks and Quasi-Symmetric Stellarators
University of Wisconsin-Madison（威斯康星大学麦迪逊分校）；Max Planck Institute for Plasma Physics（马普等离子体物理研究所）；Dutch Institute for Fundamental Research（荷兰基础研究所）；Eindhoven University of Technology（埃因霍温理工大学）；Ruhr-Universität Bochum（波鸿鲁尔大学）
