Ablation of a graphite anode by an arc is used to produce nanoparticles. The flow of the ablated carbon particles hampers access of plasma ions to the anode sheath. While the ablation rate is low, ions are still capable of reaching the sheath, where they counter the electric charge of electrons, anode voltage drop is negative. At ablation rates higher than some critical value, the flow of the ablating particles sweeps the plasma ions from the anode proximity; electron electric charge dominates in the sheath and the anode voltage drop turns positive. In these regimes, ions in the plasma move away from the anode and, therefore, they should be generated inside the sheath. The processes in the plasma in the case of positive anode voltage drop together with the process of ion generation inside the sheath are considered. The dependence of the anode voltage drop on the ablation rate is calculated and compared with available experimental data. A good correspondence is found.

中文翻译：

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用于纳米颗粒生产的碳弧：阳极烧蚀速率和阳极电压降值

通过电弧烧蚀石墨阳极用于生产纳米颗粒。烧蚀的碳颗粒的流动阻碍了等离子体离子进入阳极护套。虽然烧蚀率低，但离子仍然能够到达鞘层，在那里它们对抗电子的电荷，阳极电压降为负。在烧蚀速率高于某个临界值时，烧蚀粒子流从阳极附近扫过等离子体离子；电子电荷在鞘中占主导地位，阳极电压降变为正。在这些状态下，等离子体中的离子会远离阳极，因此它们应该在鞘层内产生。考虑了阳极正压降情况下等离子体中的过程以及鞘内离子产生的过程。计算阳极电压降对消融速率的依赖性，并与可用的实验数据进行比较。找到了一个很好的对应关系。