标题： 旋转的辐条，势垒和射频磁控放电中的调制电离 显示英文标题

标题： Rotating spokes, potential hump and modulated ionization in radio frequency magnetron discharges

摘要： 在本工作中，通过二维轴向-方位（z-y）粒子-蒙特卡洛碰撞方法观察和分析了射频（RF）磁控管放电中的旋转条纹模式，该模式具有势垒和射频调制的电离特征。 结合扰动线性分析的动能模型表明，阴极鞘层（轴向）电场$E_z$引发了梯度漂移不稳定性（GDI），使局部势能变形，直到不稳定条件不再满足，波动增长停止，在此时刻不稳定性达到饱和。 势能变形随后导致势垒的形成，围绕势垒存在方位电场$E_y$。 发现$E_y$的饱和水平与施加在阴极上的时间变化电压同步且成正比，从而由于$\nabla B$漂移导致$E_y$中电子加热的射频调制。 在不稳定性饱和阶段，显示模拟中出现的条纹旋转速度和方向与实验观测结果高度一致。 在不稳定性线性阶段，不稳定性模式波长和增长率也与GDI线性流体理论的预测良好一致。 显示英文摘要

摘要： In this work, the rotating spoke mode in the radio frequency (RF) magnetron discharge, which features the potential hump and the RF-modulated ionization, is observed and analyzed by means of the two dimensional axial-azimuthal (z-y) particle-in-cell/Monte Carlo collision method. The kinetic model combined with the linear analysis of the perturbation reveals that the cathode sheath (axial) electric field $E_z$ triggers the gradient drift instability (GDI), deforming the local potential until the instability condition is not fulfilled and the fluctuation growth stops in which moment the instability becomes saturated. The potential deformation consequently leads to the formation of the potential hump, surrounding which the azimuthal electric field $E_y$ is present. The saturation level of $E_y$ is found to be synchronized with and proportional to the time-changing voltage applied at the cathode, resulting in the RF-modulation of the electron heating in the $E_y$ due to $\nabla B$ drift. In the instability saturated stage, it is shown that the rotation velocity and direction of the spoke present in the simulations agree well with the experimental observation. In the instability linear stage, the instability mode wavelength and the growth rate are also found to be in good agreement with the prediction of the GDI linear fluid theory.