ECLIM2022

Electro-optical sensing of intense electromagnetic pulses in a multi-hundred joule laser facility

Not scheduled

20m

Bruno Brunelli Hall (Frascati)

oral Session 7

Speaker

Massimiliano Sciscio

Description

Electromagnetic pulses (EMPs) generated by the interaction between energetic laser pulses and matter represent a hazard for the safe operation of laser-plasma experiments at high-power facilities and, at the same time, they promise interesting applications where intense (up to the MV/m) pulsed fields (with durations in the order of ns) are required. Therefore, their characterization and absolute measurement is a topic of high interest. In the last years, numerous measuring techniques and devices have been implemented for detecting EMPs, in terms of both electric and magnetic component of the generated wave, among which conductive probes and electro-optical sensors have been used.
The latter have the potential advantage (over the more commonly used conductive probes) of being less subject to the interaction with plasma particles and radiation and electromagnetically couple less efficiently with surrounding metal objects, due to the absence of conductive components. These features make them very useful for EMP measurements close to the interaction point, but they were only tested in facilities with tens of Joules energy, nanosecond long laser pulses. When higher energies are involved, even electro-optical methods for EMP detection might be affected by the large amount of produced ionizing radiation.
Here we present experimental data obtained at the PALS laser facility (∼600 J pulses in 350 ps) where electro-optical detectors have been successfully implemented at short distance from target (<0.5 m). We addressed the delicate issue of high ionizing radiation produced, and we characterized the EMP emission in terms of intensity and spectral components with these probes. We compared the results with those from a conductive probe placed close to the electro-optical ones. The electro-optical probes, here used for the first time on a multi-hundred Joule facility, provided results consistent with the ones of the conductive antenna and proved therefore to be a suitable alternative of high performance for EMP measurements.