Radio frequency wave interactions with a plasma sheath: the role of wave and plasma sheath impedances

The accompanying files contain digital data for figures in the article "Radio frequency wave interactions with a plasma sheath: the role of wave and plasma sheath impedances" by J.R. Myra and H. Kohno, to be submitted to the journal Physics of Plasmas. <br> Abstract:<br> RF sheaths form near surfaces where plasma and strong RF fields coexist. The effect of these RF sheaths on wave propagation near the boundary can be characterized by an effective sheath impedance that includes both resistive and capacitive contributions describing RF sheath rectification and RF power absorption in the sheath [J. R. Myra and D. A. D'Ippolito, Phys. Plasmas 22, 062507 (2015)]. Here we define a dimensionless parameter, the ratio of incoming wave impedance to the sheath impedance, which determines the characteristics of the interaction, ranging from quasi-conducting to quasi-insulating, or in the case of matched impedances, to a sheath-plasma resonance. A semi-analytical analysis is carried out for electrostatic slow waves in the ion cyclotron range of frequencies (ICRF). For the propagating slow wave case, where the incident wave is partially reflected, the fraction of power dissipated in the sheath is calculated. For the evanescent slow wave case, which admits a sheath-plasma resonance, an amplification factor is calculated. Using the impedance ratio approach, RF sheath interactions are characterized for a range of RF wave and plasma parameters including plasma density, magnetic field angle with respect to the surface, wave frequency and wave-vector components tangent to the surface. For a particularly interesting example case, results are compared with the rfSOL code [H. Kohno and J. R. Myra, Comput. Phys. Commun. 220, 129 (2017)]. Finally electromagnetic effects, absent from the semi-analytical analysis, are assessed.随附文件包含J.R. 迈拉（J.R. Myra）与H. 今野（H. Kohno）合著的、已投稿至《等离子体物理学（Physics of Plasmas）》期刊的论文《射频波与等离子体鞘层相互作用：波与等离子体鞘层阻抗的作用》中各图表的数字化数据。 摘要： 射频鞘层（Radio Frequency sheath, RF sheath）会在等离子体与强射频场共存的表面附近形成。这类射频鞘层对边界附近波传播的影响，可以通过等效鞘层阻抗进行表征，该阻抗包含电阻性与电容性分量，用于描述鞘层内的射频鞘层整流与射频功率吸收过程[J.R. 迈拉与D.A. 迪波利托（D.A. D'Ippolito, 《等离子体物理学（Physics of Plasmas）》, 22, 062507 (2015)]。 本文定义了一个无量纲参数——入射波阻抗与鞘层阻抗的比值，该参数决定了相互作用的特性：从准导电到准绝缘的过渡，在阻抗匹配的情况下，还会出现鞘层-等离子体共振现象。 本文针对离子回旋频段（Ion Cyclotron Range of Frequencies, ICRF）中的静电慢波开展了半解析分析。 对于入射波发生部分反射的传播型慢波场景，本文计算了鞘层内耗散的功率占比。 对于存在鞘层-等离子体共振的倏逝型慢波场景，本文计算了其放大因子。 借助阻抗比值方法，本文针对一系列射频波与等离子体参数（包括等离子体密度、与表面成一定夹角的磁场、波频率以及与表面相切的波矢分量）表征了射频鞘层的相互作用特性。 针对一个极具研究价值的示例场景，本文将计算结果与rfSOL代码[H. 今野与J.R. 迈拉, 《计算机物理通讯（Comput. Phys. Commun.》, 220, 129 (2017)]进行了对比。 最后，本文评估了半解析分析中未纳入考量的电磁效应。