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In this paper, we present the study realized on three experimental setups that produce in laboratory a free arc channel subjected to the transient phase of a lightning current waveform. This work extends the high current pulsed arc characterization performed on previous studies for peak levels up to 100 kA. Eleven high current waveforms with peak value ranging from 100 kA to 250 kA with different growth rates and action integrals are studied, allowing the comparison of different test benches. These waveforms correspond to standard lightning ones used in aircraft certification processes. Hydrodynamic properties such as arc channel evolution and shock wave propagation are determined by high speed video imaging and Background-Oriented Schlieren method. The arc diameter reaches around 90 mm at 50 µs for a current of 250 kA peak. Space-and time-resolved measurements of temperature, electron density and pressure are assessed by optical emission spectroscopy associated with the radiative transfer equation. It is solved across the arc column and takes into account the assumption of non-optically thin plasma at local thermodynamic equilibrium. For a 250 kA waveform, temperatures up to 43000 K are found, with pressures in the order of 50 bar. The influence of current waveform parameters on the arc properties are analysed and discussed.

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Aims: This article shows the effect of nanosecond pulsed electric field (nsPEF) on Escherichia coli, which could imply a durable change in protein expressions and then impacted the phenotype of surviving bacteria that might lead to increase pathogenicity. Methods and Results: The effects of nsPEF on E. coli viability and membrane permeabilization were investigated. One log 10 reduction in bacterial counts was achieved at field strength of 10 7 V m À1 with a train of 500 successive pulses of 60 9 10 À9 s. Incubation of germs after treatment with propidium iodide showed that membrane permeabilization was reversible. Possible protein changes of surviving bacteria were checked to assess potential phenotypical changes using two-dimensional electrophoresis. In our study, after 40 generations, only UniProt #P39187 was up-regulated with P ≤ 0Á05 compared with the control and corresponded to the uncharacterized protein YtfJ. Antibiograms were used to check whether or not the pattern of cultivable bacteria after nsPEF deliveries changed. Conclusions:The results tend to show that nsPEFs are able to inactivate bacteria and have probably no serious impact in E. coli protein patterns. Significance and Impact of the Study: The use of nsPEF is a safe promising new nonthermal method for bacterial inactivation in the food processing and environmental industry.