大气压反常辉光放电特性

为研究大气压反常辉光放电的特性,用50 Hz交流电驱动1:500的高压变压器产生稳定的大气反常辉光放电,并利用示波器对其作了测量。维持稳态放电的典型参数为电压400~850 V,电流60~110 mA,其伏安特性曲线表明放电处于反常辉光区。当放电的原始驱动电动势取为余弦波形时,放电端电压呈方波形,放电电流呈正弦波形。对放电过程的电路分析表明,高压变压器次级线圈固有的高感抗产生的负反馈避免了放电进入弧光区,由于电路的感抗特性,余弦电动势驱动了正弦形放电电流。而等离子体电阻对放电电流的非线性响应使得放电端电压呈近似方波形。估算得到放电通道中电子平均温度和电子密度分别为2.73 eV和3.45μm-3。用热电偶测得等离子气体温度为700~900 K。该种等离子体相对于其它冷等离子体具有较高的等离子体气体温度和能量密度,更适宜于一些化学气相反应。

Character of Atmospheric Pressure Abnormal Glow Discharge

Atmospheric pressure abnormal glow discharge(APAGD) was generated simply with a transformer of 1:500 driven by 50 Hz alternating current.The discharge characteristic was detected by oscillograph.It showed that the parameter domain for stable discharge was 400-850 V of voltage,60-110 mA of current.The I-U characteristic measured by oscillograph verified the discharge was an abnormal glow discharge mode.Though the original electromotive potential was cosine-like,the discharge current behaved sinuous and the voltage between electrodes was square-like.Simulation for discharge process suggested that stable discharge be supported by the inherent impedance from secondary coil of the transformer,which offered a negative feedback to avoid the discharge into arc and drived the sine-like current.The square-like voltage on generator was due to the nonlinear response of plasma resistance to discharge current.Furthermore,the electron temperature and electron density averaged in discharge channel were estimated.Also the gas temperature of the plasma was 700~900 K measured by digital thermocouple.Compared with other cold plasma,atmospheric pressure abnormal glow discharge had a higher temperature and higher energy density in reaction spaces.These characteristics provided the discharge with the advantages of both thermal plasma and cold plasma.This kind of plasma was preferable to some chemical gas reactions.