中文摘要：

利用10 kHz的正弦波高压电源驱动在大气环境中产生了稳定的Ar等离子体射流。结合射流的图像,基于Ar在空气中的摩尔分数分布和不同放电位置处光谱的变化,研究了Ar和空气之间的交互影响。随着外加电压的升高射流经历三个阶段：低电压阶段,射流刚能产生,长度较短,Ar在放电中起主导作用;中电压阶段,放电沿射流通道发展,射流长度逐渐增加,在射流的前端Ar与空气的最强光谱强度大致相当;高电压阶段,射流前端流注头携带的能量更大,足以电离空气含量更大的混合气体,此时射流长度线性缓慢增加,整体变粗,并且呈现剑状。研究发现在射流向空气传播的过程中,Ar的各谱线强度衰减速率不同,这可能是激发态的氩原子与基态的氮分子发生了近共振能量转移碰撞导致的。最后分析了射流光谱中OH自由基谱线的产生及减弱的原因,发现空气在其中发挥着重要的作用。

英文摘要：

The interaction of air and the argon-plasma jet, generated in the ambient environment and driven by 10 kHz sinuseidal high voltage, was investigated by evaluating its image, its Ar mole fraction distribution and its spectrum emitted from different spots.As the voltage increases, three growth stages of the jet were identified. In the 1st stage,a low voltage, about 4.3 kV, initiates the short plasma jet, growing in length with an increasing voltage; in the 2nd stage, a volt- age, ranging from 5 ~ 7 kV, associates with a long needle-shaped jet along the Ar-channel and with steady discharge; and in the 3rd stage, a voltage, around 9 - 10 kV, correlates with a jet resembling a thin-waisted conical spike and a strong dis- charge. The jet becomes longer and thicker possibly because of the field ionization of some species in air. The voltage-de- pendent decay rate of Ar spectral intensity, observed in jet propagation in air, may possibly stem from the resonant energy transfer in collision between ground-stated N2 molecules and Ar atoms . We found that air strongly affects the emerging and weakening of the OH radicals in the spectrum.