Abstract

The evolution of the kinetics of plasma moving from the outlet of a plasma torch to the object of impact is studied in order to study the effectiveness of action of a nitrogen plasma flow on graphite surfaces. The motion is accompanied by a decrease in temperature from 10 to 7 kK with a loss of ~60% of the input energy and an increase in the density of carbon-containing admixtures with partial conservation of the local thermodynamic equilibrium. The main reactions are the thermal processes of the formation and dissociation of molecules, the dissociative recombination and recharge of nitrogen ions, and, in the presence of carbon admixtures, the substitution reaction С + N₂ ↔ CN + N, the electron-collisional processes of stepwise ionization and recombination, and the entire ionic–molecular cascade of recharges and substitutions. It is found that a small amount of carbon impurity (~0.1%) manifests itself only in ionic–molecular kinetics. It increases the electron concentration, determines the ionic composition of the plasma, and thereby violates the equilibrium between its neutral and charged components. This leads, in particular, to a recombination nonequilibrium of distribution of carbon atoms over the electron states. Other carbon-containing impurities (CN and C₂) are insignificant.

中文翻译：

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含碳混合物的氮等离子体流过程的动力学

摘要

为了研究氮等离子流在石墨表面上的作用效果，研究了从等离子炬出口到撞击对象的等离子动力学变化。运动伴随着温度从10 kK降低到7 kK，损失约60％的输入能量，含碳混合物的密度增加，局部保持了局部热力学平衡。主要反应是分子形成和解离的热过程，氮离子的解离重组和再充电，以及在存在碳混合物的情况下的取代反应С+ N ₂↔CN + N，逐步电离和重组的电子碰撞过程以及整个离子-分子级的电荷和取代级联。发现少量的碳杂质（〜0.1％）仅在离子分子动力学中表现出来。它增加了电子浓度，确定了等离子体的离子组成，从而违反了其中性和带电成分之间的平衡。特别地，这导致碳原子在电子态上的分布的重组不平衡。其他含碳杂质（CN和C ₂）微不足道。