中文摘要：

为了研究电极结构对大气压等离子体射流放电特性的影响，通过氩等离子体射流的电压电流波形和Lissajous图形等电气特性的测量以及发射光谱及发光图像的光学特性的诊断，研究了内电极直径对氩等离子体射流放电特性的影响。实验研究了内电极直径分别为0．5、0．95、1．6mm时，氩等离子体射流放电的演变规律，并进一步计算得到了放电功率、传输电荷、电子激发温度、分子转动温度和振动温度等，分析了它们随内电极直径变化的规律及机理。结果表明，氩等离子体射流放电可分为电晕放电、DBD以及射流形成3个阶段，这3个阶段可通过测得的电气特性和发光特性进行区分。内电极直径对氩射流特性的影响主要表现在射流阶段：随着电极直径逐渐减小，放电面积增加，放电变强，相应的放电电流脉冲的幅度和激发态粒子数量增加，放电功率和传输电荷也更多。内电极直径越小，分子振动温度、分子转动温度和电子激发温度也越小。分子振动温度和分子转动温度随电压幅值的增加而增大。

英文摘要：

We experimentally investigated the discharge characteristics of Ar atmosphere pressure plasma jet （APPJ） with inner electrodes of different radii by means of electrical measurements （including voltage-current waveforms and Lissaj- ous figures） and optical diagnosis （including emission spectra and light-emission pictures） to understand the effect of electrode arrangement on the characteristics. With inner electrode of 0.5 mm, 0.95 mm and 1.6 mm in diameter, we ob- served the changing of APPJ in Ar, obtained some main discharge parameters including discharge power, transported charges, electronic excitation temperature, molecular vibrational temperature and molecular rotational temperature through further calculation, and explained the experimental results through analyzing the discharge mechanism. The re- suits show that the discharge process of APPJ in Ar can be divided into three phases, namely corona, dielectric barrier discharge （DBD） and plasma jet, which can be distinguished obviously by electrical characteristics and light-emission pictures. The influence of inner electrode＇s diameter on APPJ in Ar mainly shows in plasma jet stage： Ar volume in tube increases with decreasing inner electrode diameter; this increases discharge area and enhances discharge, and accordingly the pulsed current peak, discharge power and transported charges all become larger. For the APPJ in Ar, smaller inner electrode corresponds to lower rotational temperature and vibrational temperature of molecular and lower excitation tem- perature of electrons, while the rotational temperature and vibrational temperature of molecular increase with applied voltage.