Simulations of the interaction of high-power microwave (HPM) pulses with air-SF
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mixtures at high pressure in the fluid model are presented, where various reaction sets of air and SF
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are taken into account. Introducing a small amount of SF
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in air can drastically increase the breakdown threshold. At a higher pressure or for a larger pulse width, the breakdown threshold increases more significantly as the percentage of SF
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in the mixture increases. The amplitude of the transmitted pulse in the air breakdown decreases with time and its width is shortened. Due to the higher attachment frequencies in the air-SF
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mixture and SF
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, the amplitude of the transmitted pulse keeps almost unchanged after it experiences a short-time attenuation, and the pulse width is not strongly influenced. Most of the energy loss of the transmitted pulse in the gas breakdown propagates in the opposite direction, and the rest of energy loss is due to electron heating. The accuracy of the fluid model is verified by experimental results.
