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С использованием метода лазерного зондирования исследован искровой разряд в промежутке острие (катод)-плоскость длиной 1.5 mm в интервале времени от момента пробоя до 200 ns. Установлено, что разряд развивается в виде пучка микроканалов. Определена динамика пространственной структуры разряда, концентрации электронов, температуры газа в канале и скорости его радиального расширения. Ключевые слова: искровой разряд, микроструктура, интерферометрия, концентрация электронов.

The results of studies of the microstructure in the initial phase of the discharge in air in the gap between the pin and a plane 1.5 mm long are presented. Measurements show that within 15 ns after breakdown, the channel is a bundle of a large number of microchannels, the current in the channel grows almost linearly up to 1 kA, and the electron concentration reaches 2 × 1019 cm−3. Taking into account the experimental data, the electron temperature dynamics in a separate microchannel was calculated. It was found that the average electron temperature is from 4 to 8 eV, the electric field strength is ∼300 kV/cm, and the electrical conductivity is ∼10 Ω−1 cm−1. The obtained results indicate that it is the microstructure of the discharge that determines the relatively high values of the average temperature of electrons in combination with a sufficiently high degree of ionization.

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The formation of the microchannel structure of a spark dischargein the gap spike (cathode)-plane of 1.5 mm length in the air of atmosphericpressure was studied by the method of shadow photography.The images with the concurrent descent of microchannel diameter sand thenumber of microchannel increase in the cathode region on the time intervalof 5 ns were recorded. The obtained data are explained in the frames ofthemicrostructure formation mechanism at the expense of the front instabilityof the ionization wave. The parameters characterizing the process of themicrostructure formation are estimated, and they agree with the experimentaldata. Keywords: spark discharge, ionization wave, ionization instability, microstructure, method of shadow photography.\