Research and development on the technologies for transport and application of “Giga-watts-class short-pulse microwave"

新型高功率微波源是最近由俄罗斯理论界提出并由我国自行研制的高功率微波源。这种类型的高功率微波的特点是脉冲强烈而尖锐。HPM振荡器工作在超辐射区域，在SR区域，能量从电子束单向流向HPM，且不反转。虽然单脉冲总焦耳较低，但高功率微波具有较强的电场。HPM的峰值功率从几兆瓦到几吉瓦，大约是恒波型振荡器的几千倍。它可以在自由空间的气体中引起击穿，并产生等离子体。这种应用不仅适用于雷达(无线电探测和测距)，例如，在大型和高温等离子体中的诊断。HPM还将实现基础等离子体科学的其他独特方法。它可以应用于自由空间的等离子体产生、非线性现象的研究、介质表面烧蚀等。在本研究中，我们研究了包括SR的产生和这些应用的输运。我们已经为5 GHz的HPM研制出了功能强大的BWO。这一次，权力变得更大了。为了在自由空间实现更高的功率密度，研制了10 GHz高频宽带宽带光天线。本文对一种被称为“弗拉索夫天线”的准光天线进行了深入的研究。它使从波导向自由空间发射高功率微波成为可能。对几种天线设计进行了测试，并对其在6 cm，即5 GHz波段的转换效率进行了研究。与波导的直径相比，波长并不短。增加最终波导的直径可以提高转换效率。在实验中，它从15%变化到75%。

New type of high power microwave sources, HPM, are recently proposed by Russian theorist and developed by us. This type of HPM is characterized by a strong sharp pulse. The oscillator of HPM is operated in superradiative regime, “SR" In the SR regime, energy flows from electron beam to HPM in one direction, and is not reversed. The HPM has strong electric field, though the total joule per one pulse is low. The peak power of HPM is a few Mega-watts to a few Giga-watts, which is about thousands times larger than the constant wave type oscillators. It can induce breakdown in the gas in free space, and produces plasma. The application is not only for radar (radio detection and ranging), for example, diagnostic in large and high temperature plasma. HPM will realize other unique methods to basic plasma science. It can be applied to plasma production in free space, study on non-linear phenomena, ablation on dielectric surface, etc. In this research, we studied the generation that includes SR, and the transport for these applications.Backward wave oscillator, BWO, is one of the most powerful microwave source for Giga-watts. Powerful BWO is already developed for HPM of 5 GHz by us. This time, the power became much higher. BWO for higher frequency, 10 GHz, is newly developed to achieve higher power density in free space.A quasi-optical antenna, called “Vlasov antenna", is studied intensively in this research. It makes possible launching HPM from waveguides to free space. Several antenna designs are tested and its conversion efficiency is investigated at the wavelength 6 cm, i. e. 5 GHz. The wavelength is not short compared to the diameter of wave guide. The conversion efficiency can be improved by increasing the diameter of the final waveguide. It changes from 15% to 75% in the experiment.