Speaker
Description
When a high-intensity laser interacts with matter, it creates a plasma, thus emitting particles and generating strong electromagnetic (EM) radiation. We focus for this study on the emitted EM fields ranging from MHz to THz, known as electromagnetic pulses (EMPs). These EMPs, originating from various sources in laser-matter interactions [1], can reach peak intensities of the MV/m order, posing risks to electronic devices, spoiling the measurements, and being harmful to individuals. The study of EMPs is then of primary importance in laser-matter experiment to know how to mitigates them. However, they also proved their interest in many applications such as medicine, defense, and aerospace.
Various detectors are typically employed for EMP characterization [2]; this work investigates the possibility of using Thomson Spectrometry which is a commonly used diagnostic in many laser-matter experiment, as an alternative diagnostic tool. This device detects and differentiates laser-accelerated ions, according to their charge-to-mass ratio, via combined electrostatic and magnetostatic fields, producing characteristic parabolic traces on the detector. However, under the influence of EMPs, the particles that enter the spectrometer deviate from their ideal trajectory, producing modulations and ripples on the detected signals, which encode information on the transient electromagnetic fields.
We present an analysis of such EMP-induced distortions, observed during an experiment of high-power laser-plasma interaction, performed with a kJ-class laser at the Prague Asterix Laser System (PALS). This experiment gives a unique opportunity to correlate the spectral deformation of ion parabolas with EMP activity inside the interaction chamber.
Previous investigations mainly focused on EMP-induced distortions of proton signals [3], in this work, we extend the methodology to heavier ions, whose parabolic traces carry complementary information on the EMPs strength. The analysis highlights similarities in the modulations shape and amplitude between proton-associated distortions and those affecting heavier ion traces.
These results demonstrate that the Thomson Spectrometer, traditionally employed for ion diagnostics, can also serve for EMP characterization.
References
[1] Consoli F, Tikhonchuk VT, Bardon M, et al. 2020;8:e22. doi:10.1017/hpl.2020.13
[2] Consoli F et al., Phil. Trans. R. Soc. A 379: 20200022 (2021)
[3] Grepl, F. et al., Appl. Sci. 11, 4484 (2021)
Acknowledgements:
This work is supported by PALS “FUSION: Maximizing the p(11B, a)2a reaction using in-plasma and pitcher target configurations and novel target design” (PID: 26286) financed by LaserLAB Europe and partially supported by INFN-FUSION Experiment. This work has been partially carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No. 101052200—EUROfusion). Views and opinions expressed are, however, those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission.
