The effects of magnetic field and negative DC voltage on the capacitive argon discharge
The effects of magnetic field and negative DC voltage on the capacitive argon discharge
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DOI：
10.1063/5.0171740
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发表时间：
2023-11
影响因子：
3.2
通讯作者：
Shali Yang;Minghan Yan;H. Lin;Huanhuan Wu;Hao Wu;Yanli Peng
中科院分区：
文献类型：
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作者：
Shali Yang;Minghan Yan;H. Lin;Huanhuan Wu;Hao Wu;Yanli Peng
采用一维隐式粒子模拟方法研究了均匀弱磁场和负直流电压对射频电容耦合等离子体（CCP）的影响.模拟结果表明，在射频/直流混合电源驱动的等离子体放电中施加磁场，可以提高等离子体密度，并使其呈现非对称分布。当磁场强度增加时，在电子加热率和电离率的时空图中可以观察到DC鞘内的明显条纹。这归因于DC电极产生大量二次电子。这些二次电子被鞘层电压加速并经历E × B漂移运动。当这些电子的能量达到氩气的电离阈值时，发生电离。在这一点上，电子仍然位于DC鞘层内，因此，它们重复地经历这个过程，直到它们离开DC鞘层。此外，电子能量分布函数揭示了磁场的增加可以引起从随机加热到欧姆加热的转变。负直流电压影响下的磁化等离子体放电模拟结果表明，增加负直流电压可以有效提高等离子体密度。施加负直流电压和磁场强度对加热条纹现象的影响相似。随着负直流电压的增加，条纹现象变得更加明显。
A one-dimensional implicit particle-in-cell/Monte Carlo collision simulation was employed to study the effects of a uniform weak magnetic field and negative direct-current (DC) voltage on a radio frequency capacitively coupled plasma (CCP). The simulation results indicate that the application of a magnetic field to RF/DC hybrid power-driven CCP discharge can increase the plasma density and cause it to exhibit an asymmetric distribution. When the magnetic field strength increases, pronounced striations can be observed within the DC sheath in the spatiotemporal plots of an electron heating rate and an ionization rate. This is attributed to the generation of a large number of secondary electrons by the DC electrode. These secondary electrons are accelerated by the sheath voltage and undergo E × B drift motion. When the energy of these electrons reaches the ionization threshold of an argon gas, ionization occurs. At this point, the electrons are still situated within the DC sheath, and hence, they repeatedly undergo this process until they exit the DC sheath. Additionally, the electron energy distribution function reveals that an increase in a magnetic field can cause a transition from stochastic heating to ohmic heating. The simulation results of magnetized CCP discharge under the influence of negative DC voltage show that increasing negative DC voltage can effectively improve plasma density. The application of negative DC voltage and magnetic field strength has similar effects on the heating stripe phenomenon. As the negative DC voltage increases, the striation phenomenon becomes more pronounced.