Abstract—

Electrodynamic characteristics of a low-pressure (electron collision frequency much lower than the field frequency) capacitive HF discharge maintained by an electromagnetic field with a frequency between 13 and 900 MHz are studied analytically and numerically. It is demonstrated that the field of both the fundamental mode (the field in the metal–space-charge sheath–plasma–space-charge sheath–metal structure) and the field of the higher-order evanescent modes must be taken into account for correct calculation of discharge characteristics under such conditions in a wide range of electron densities. Expressions governing the amplitudes of excited waves, along with expressions governing the discharge impedance in the presence of these waves, are derived by using field expansion in eigenwaves of an empty waveguide and eigenmodes of the three-layer structure. The case in which the size of plasma is smaller than the size of the electrodes is analyzed in detail. In this case, excitation of higher-order types of waves in the plasma column is generated by axial plasma inhomogeneity and is not related to electrodynamic effects near the electrode boundaries. It is demonstrated that the positions of current and voltage resonances related to propagation of surface waves along the three-layer structure becomes substantially modified due to excitation of higher-order field modes of the same structure. In addition, resonances caused by excitation of standing surface waves near the lateral surface (resonances of higher-order modes of the three-layer structure and an empty waveguide) can take place. Variation of relative position of resonances caused by changes in the discharge chamber geometry is investigated. Obtained results qualitatively agree with the results of numerical calculation of the discharge impedance and field propagation in the discharge by COMSOL Multiphysics^® software package.

中文翻译：

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电容性HF放电中的电磁场激励特性。三，对称排放部分填充了排放室

摘要-

通过分析和数值研究了由电磁场保持的低压（电子碰撞频率远低于电场频率）电容性HF放电的电动力特性。结果表明，必须考虑基本模式的场（金属-空间电荷鞘-等离子体-空间电荷鞘-金属结构中的场）和高阶渐逝模式的场。在很宽的电子密度范围内，在这种条件下计算放电特性。控制激发波幅度的表达式，以及控制存在这些波时的放电阻抗的表达式，通过使用空波导的本征波中的场扩展和三层结构的本征模来推导它们。详细分析等离子体的尺寸小于电极的尺寸的情况。在这种情况下，等离子体列中更高阶类型的波的激发是由轴向等离子体不均匀性产生的，并且与电极边界附近的电动力效应无关。已经证明，由于激发相同结构的高阶场模，与表面波沿三层结构的传播有关的电流和电压谐振的位置变得基本上改变了。另外，由于侧面附近的立面波的激发而引起的共振（三层结构和空波导的高阶模式的共振）会发生。研究了由放电室几何形状的变化引起的共振的相对位置的变化。获得的结果与COMSOL Multiphysics对放电阻抗和放电中的场传播进行数值计算的结果在质量上吻合^®软件包。