Potential and density structures in the vicinity of an radio frequency (RF) electrode/antenna in a magnetized plasma are investigated using an RF‐compensated cylindrical Langmuir probe. These measurements were performed in the ALINE plasma device in which only electrons can be considered well magnetized. Very precise 2‐D maps of the plasma parameters are drawn thanks to a 3‐D automatic manipulator on which the probe is mounted. The effect of the tilted magnetic angle between the RF‐biased surface and the magnetic lines is also studied thanks to a tilting electrode. Comparison of several simplistic models with the experiments proved the reliability of simple Langmuir probe measurements in such an RF and magnetized environment (space potential vs. tilting angle of the antenna with respect to magnetic field lines and recovery of the floating potential structure using measured currents). A fluid model based on total current density and ion diffusion equations over the biased flux tube provides the same density structures in front of the electrode as the measurements. Those density structures display a “bunny ears” shape and can be explained using transverse RF and collisional current behaviour: In front of the antenna, the transverse ion currents deplete the magnetized flux tube, while at the edge of the biased flux tube, the same currents increase the density.

中文翻译：

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相对于磁力线倾斜的射频天线前面的氦等离子体的密度，电势和电流结构的实验和理论研究

使用射频补偿圆柱型Langmuir探针研究磁化等离子体中射频（RF）电极/天线附近的电位和密度结构。这些测量是在ALINE等离子设备中执行的，在该设备中，只有电子可以被磁化。由于安装了探头的3D自动操纵器，可以绘制出非常精确的2D血浆参数图。借助倾斜电极，还可以研究RF偏置表面和磁力线之间倾斜的磁角的影响。几种简单模型与实验的比较证明了在这样的RF和磁化环境中简单的Langmuir探头测量的可靠性（空间电势vs. 天线相对于磁力线的倾斜角和使用测得的电流恢复浮动电位结构。基于总电流密度和离子流在偏流管上的扩散方程的流体模型在电极前提供了与测量相同的密度结构。这些密度结构显示为“兔子耳朵”形状，可以用横向RF和碰撞电流行为来解释：在天线前面，横向离子流耗尽了磁化通量管，而在偏置通量管的边缘，相同电流增加了密度。