Abstract:
A numerical and experimental study of the trace temperature of a microwave discharge initiated by a laser in air is carried out. The amplitude of the microwave field strength is 2.0 kV/cm, discharge is ignited at pressures up to 6.66 kPa; the duration of the microwave radiation pulse is 2.5 $\mu$s. The use of 10 ns laser pulses with an energy of 200 mJ and a wavelength of 532 nm makes it possible to obtain an initiated subcritical microwave discharge at a pressure of 10.6 kPa. The dependences of the discharge trace temperature on time with initiation up to 200 $\mu$s and a pressure of 5.33–10.0 kPa are given. The trace of the discharge is hot, the temperature is about 1000 K, which corresponds to the trace of a filament discharge. The numerical model confirms the possibility of obtaining a filament subcritical microwave discharge at low pressures of about 10 kPa in a few $\mu$s due to laser initiation. The model is based on those known in the literature and is modified with explicit consideration of photoeffects during the solution. The consistency of the results of trace temperature calculations and interferometry, taking into account the uncertainty of 25%, is achieved in the first 20 $\mu$s after switching off the microwave radiation.
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