Abstract

In the subthreshold microwave discharge (the wavelength of 4 mm) in argon at the pressure of 750 Torr at intensities of the wave beam from 3 to 7.8 kW/cm², the velocity of the ionization front, measured from the phase change of the reflected wave, increases approximately as the intensity on the wave beam axis in the power of 3/2 from 0.5 × 10⁵ to 2.9 × 10⁵ cm/s. This velocity of the discharge front in argon is 20–30 times higher than the velocity of the discharge front in air at the same intensities in the microwave beam. The glow structure of the discharge at intensities higher than 3 kW/cm² is similar to the glow structure in molecular gases. An even finer structure of the discharge is observed at glow intensities on the wave beam axis below 3 kW/cm². The gas temperature in the discharge at radiation intensity of 6 kW/cm² is 6 kK. It is concluded that the volume of high-temperature regions in the discharge is 0.01 of the volume of the discharge region. The problem of the mechanism of the argon ionization and the possibility of the development of ionization-overheating instability in a non-self-sustained microwave discharge in the UV halo of the discharge front are discussed.

中文翻译：

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亚阈值微波场中大气压下氩气中超音速电离波的特征

摘要

在3到7.8 kW / cm ^2的光束强度下，在750 Torr压力下的氩气中的亚阈值微波放电（波长为4 mm）中，电离锋的速度是从反射的相变测量的大约在3/2的功率范围内随着光束轴上的强度从0.5×10 ⁵增大到2.9×10 ⁵ cm / s。在相同的微波束强度下，氩气放电前沿的速度比空气放电前沿的速度高20-30倍。强度高于3 kW / cm ²的放电的辉光结构与分子气体中的辉光结构相似。在低于3kW / cm ^2的光束轴上的辉光强度下观察到放电的甚至更精细的结构。辐射强度为6 kW / cm ²的放电中的气体温度为6 kK。结论是放电中的高温区域的体积为放电区域的体积的0.01。讨论了在放电前沿的紫外光晕中，非自持微波放电中氩离子化机理的问题以及发展电离过热不稳定性的可能性。