Comparative investigation of resistance and ability to trigger high voltage discharge for single and multiple femtosecond filaments in air

A comparative investigation of resistance and ability to trigger high voltage (HV) discharge for single filament (SF) and multiple filaments (MF) has been carried out. The experimental results show that the trend of the breakdown threshold of the SF exactly follows that of its resistance, but this is not the case for the MF. The MF's resistance is much smaller than SF's. However, the MF shows a bit higher HV breakdown threshold than the SF. The underlying physics is that the measured resistance of the MF is collectively contributed by every filament in the MF while the HV breakdown threshold is determined by only one single discharging path.