AI 中文总结
介绍北极星这一新型小型仿星器实验，其采用模块化线圈设计，通过射频天线产生等离子体，具备实验灵活性，能测量多种等离子体参数，为仿星器边缘物理研究提供首个试验台。
AI 中文摘要
我们介绍了位于瑞士等离子体中心的新型小型仿星器实验北极星（大半径R~0.4米）的设计、建造和首次等离子体实验。北极星有一个主要由玻璃窗制成的较大真空容器（~0.5立方米），内部可安装不同的磁线圈组。设计了第一种模块化线圈配置，六个相同的圆形水冷铜线圈以最佳方式环形排列，在真空中产生大量磁面和旋转变换（iota~0.3）。每个线圈的总电流高达~5kA，轴上磁场B~0.03T。专门设计用于在真空中运行的射频天线通过感应耦合和电子碰撞电离提供高达2.5kW的功率来产生等离子体。我们展示了北极星设计所采用的工程解决方案，并说明了它所具备的巨大实验灵活性。在不同环形位置测量了等离子体密度、电子温度和浮动电位的时间平均值及波动情况，这有助于深入了解等离子体平衡、静电湍流及相关输运。北极星的玻璃真空室还为整个等离子体体积提供了前所未有的光学通道。凭借其独特、灵活的设计，北极星是一个‘仿星器鱼缸’，允许使用可互换的线圈组并探索各种磁配置。此外，其低温、低密度、高中性压力等离子体与仿星器边缘物理相关，使北极星成为研究仿星器边缘相关物理基础的首个试验台。
英文摘要
We present the design, construction, and first plasma experiments of Polaris, a new small-scale stellarator experiment (major radius R ~ 0.4 m) located at the Swiss Plasma Center. Polaris consists of a relatively large vacuum vessel (~0.5 m^3) predominantly made of glass windows and inside which different sets of magnetic coils can be installed. A first modular coil configuration has been designed with six identical, circular, water-cooled copper coils toroidally arranged in an optimal way so that they generate a large volume of magnetic surfaces and rotational transform in vacuum (iota ~ 0.3). The total current in each coil goes up to ~ 5 kA, producing a magnetic field on-axis of B ~ 0.03 T. An RF antenna specifically designed to operate in vacuum delivers up to 2.5 kW of power to produce plasma via inductive coupling and electron-impact ionization. We present the engineering solutions adopted for the design of Polaris and illustrate the great experimental flexibility it enables. Time-averaged values and fluctuations of plasma density, electron temperature, and floating potential are measured at various toroidal locations, providing insights into the plasma equilibrium, electrostatic turbulence, and associated transport. The glass vacuum chamber of Polaris additionally provides unprecedented optical access to the entire plasma volume. With its original, flexible design, Polaris is a 'stellarator fish-tank', allowing interchangeable coil sets and exploration of various magnetic configurations. Furthermore, its low-temperature, low-density, high-neutral-pressure plasmas are relevant to stellarator edge physics, making Polaris a first-of-kind testbed for the fundamental investigation of stellarator edge-relevant physics.
