发表机构
École Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在TORPEX环形装置中首次详细表征了螺旋波，发现主导m=+1模式，振幅随功率线性增加并饱和，且与低频湍流存在非线性耦合。
AI 中文摘要
螺旋波被广泛用于低温装置中的高效等离子体产生，并最近作为聚变等离子体中电流驱动的候选方案而受到关注。然而，关于螺旋波在环形几何结构中的实验研究，以及它们与等离子体动力学的相互作用，仍然极为有限。在本工作中，我们展示了据我们所知首次在环形位形中对螺旋波进行的详细实验表征。一个工作在13.56 MHz的鸟笼式谐振天线被用于在环形基础等离子体物理装置TORPEX中发射螺旋波，既可以注入到预先存在的磁控管产生的等离子体中，也可以作为等离子体源。测量在纯环形和简单磁化环的磁位形中进行，分别使用氩气和氢气等离子体。三轴磁探针测量使我们能够在我们的参数空间内清晰识别出一个占主导的m=+1螺旋波模式。发现螺旋波振幅与天线功率呈线性关系，并随约束磁场幅度的增加而减小。当天线功率增加时，螺旋波振幅出现饱和，这与增强的低频涨落和湍流输运相关。此外，观察到螺旋波与低频密度涨落之间的强相互作用，揭示了射频波与等离子体湍流之间的非线性耦合。这些结果提供了在环形低温等离子体装置中螺旋波的首次详细实验表征，并确立了TORPEX作为在受控且诊断良好的条件下研究环形螺旋波物理的独特试验平台。
英文摘要
Helicon waves are widely used for efficient plasma production in low-temperature devices and have recently attracted attention as a candidate for current drive in fusion plasmas. Yet experimental investigations of helicon waves in toroidal geometries, and of their interaction with plasma dynamics, remain extremely limited. In this work, we present, to our knowledge, the first detailed experimental characterization of helicon waves in a toroidal configuration. A birdcage resonant antenna operating at 13.56 MHz is used to launch helicon waves in the toroidal basic plasma physics device TORPEX, either into a pre-existing magnetron-generated plasma, or as the plasma source. Measurements are performed in pure toroidal and simple magnetized torus magnetic configurations, for both argon and hydrogen plasmas. Three-axis magnetic probe measurements enable clear identification of a dominant m=+1 helicon mode over our parameter space. The helicon amplitude is found to scale linearly with the antenna power, and decreases with the confining magnetic field amplitude. As the antenna power is increased the helicon amplitude exhibits a saturation, correlated with enhanced low-frequency fluctuations and turbulent transport. In addition, a strong interaction between helicon waves and low-frequency density fluctuations is observed, revealing a non-linear coupling between RF waves and plasma turbulence. These results provide the first detailed experimental characterization of helicon waves in a toroidal low-temperature plasma device and establish TORPEX as a unique testbed for studying toroidal helicon wave physics under controlled and well-diagnosed conditions.
