Nonlinear plasma structures in the partially magnetized $\mathrm{E}\times \mathrm{B}$ plasma of a cylindrical magnetron are investigated using 2D3V particle-in-cell Monte Carlo collision simulations. In the early phase of the discharge, plasma gradients and radial electric fields excite a lower hybrid type instability that forms long wavelength rotating density spokes. As the discharge grows in density by ionization and the cathode gets shielded by the formation of an ion sheath, radial electric fields diminish in the quasineutral region of the discharge. This induces a transition of the spokes into short-scale spoke-on-spoke modes. The short wavelength structures can be reversed back into a long spiral spoke by lowering the neutral pressure, which revives the radial electric fields via a turbulent plasma expansion. Plasma phenomena connected to the rotating spoke include the anomalous radial transport and loss of electrons through the spoke, azimuthal dragging of ions by the spoke’s field, plasma temperature modulations by the spoke structure, and formation of electron vortices around equipotential islands, in some cases with opposing rotations to the underlying $\mathrm{E}\times \mathrm{B}$ drift. Electron scattering from non-ionizing collisions with neutrals also has a minor influence on the instability.

中文翻译：

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响应径向电场和圆柱形磁控管等离子体中性压力变化的旋转辐条重构

部分磁化的非线性等离子体结构 $\mathrm{乙}\times \mathrm{乙}$使用 2D3V 细胞内粒子蒙特卡罗碰撞模拟研究了圆柱形磁控管的等离子体。在放电的早期阶段，等离子体梯度和径向电场激发较低的混合型不稳定性，形成长波长旋转密度辐条。随着放电因电离而密度增加，并且阴极因离子鞘的形成而被屏蔽，因此放电的准中性区域中的径向电场减弱。这导致辐条转变为短尺度辐条对辐条模式。通过降低中性压力，短波长结构可以反转回长螺旋辐条，这通过湍流等离子体膨胀恢复径向电场。$\mathrm{乙}\times \mathrm{乙}$漂移。与中性粒子的非电离碰撞产生的电子散射对不稳定性也有轻微影响。