Measurements and kinetic modeling of energy coupling in volume and surface nanosecond pulse discharges
Measurements and kinetic modeling of energy coupling in volume and surface nanosecond pulse discharges
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DOI：
10.1088/0963-0252/22/1/015013
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发表时间：
2012
影响因子：
3.8
通讯作者：
K. Takashima;Z. Yin;I. Adamovich
中科院分区：
文献类型：
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作者：
K. Takashima;Z. Yin;I. Adamovich
利用纳秒脉冲放电等离子体成像、耦合脉冲能量测量和动力学建模，分析了高重复率、空间均匀、纳秒脉冲在平面几何空气中的能量耦合机理。在这些条件下，耦合脉冲能量几乎与压力（数密度）成线性关系，每个分子耦合的能量几乎是恒定的，与动力学模型预测很好地吻合。尽管击穿前达到了峰值电场，E/N ~ 500-700 Td，击穿后等离子体中的电场要低得多，E/N ~ 50-100 Td，预测耦合到空气等离子体的很大一部分能量，高达30-40%，被加载到氮振动模式。建立了一个自相似的局部电离动力学模型，预测了纳秒电压脉冲产生的表面电离波放电中与等离子体的能量耦合。该模型预测了电离波速度和传播距离、电场、电子密度、等离子体层厚度、耦合到等离子体的脉冲能量等关键放电参数，与实验数据和二维动力学建模计算结果具有较好的定性一致性。该模型提供了一个解析解，并可与现有的可压缩流代码相结合，以极低的计算成本，对纳秒放电等离子体流控制机制进行深入分析。该模型的使用将主要强调由排放产生的局部热扰动与通过压缩波的流动的耦合，并将在长时间尺度上定量地了解流动控制机制。
Nanosecond pulse discharge plasma imaging, coupled pulse energy measurements, and kinetic modeling are used to analyze the mechanism of energy coupling in high repetition rate, spatially uniform, nanosecond pulse discharges in air in plane-to-plane geometry. Under these conditions, coupled pulse energy scales nearly linearly with pressure (number density), with energy coupled per molecule being nearly constant, in good agreement with the kinetic model predictions. In spite of high-peak reduced electric field reached before breakdown, E/N ∼ 500–700 Td, the reduced electric field in the plasma after breakdown is much lower, E/N ∼ 50–100 Td, predicting that a significant fraction of energy coupled to the air plasma, up to 30–40%, is loaded into nitrogen vibrational mode. A self-similar, local ionization kinetic model predicting energy coupling to the plasma in a surface ionization wave discharge produced by a nanosecond voltage pulse has been developed. The model predicts key discharge parameters such as ionization wave speed and propagation distance, electric field, electron density, plasma layer thickness, and pulse energy coupled to the plasma, demonstrating good qualitative agreement with experimental data and two-dimensional kinetic modeling calculations. The model allows an analytic solution and lends itself to incorporation into existing compressible flow codes, at very little computational cost, for in-depth analysis of the nanosecond discharge plasma flow control mechanism. The use of the model would place the main emphasis on coupling of localized thermal perturbations produced by the discharge with the flow via compression waves and would provide quantitative insight into the flow control mechanism on a long time scale.