摘要
Low-density polymer foams pre-ionized by a well-controlled nanosecond pulse are excellent plasma targets to trigger direct laser acceleration(DLA)of electrons by sub-picosecond relativistic laser pulses.In this work,the influence of the nanosecond pulse on the DLA process is investigated.The density profile of plasma generated after irradiating foam with a nanosecond pulse was simulated with a two-dimensional hydrodynamic code,which takes into account the high aspect ratio of interaction and the microstructure of polymer foams.The obtained plasma density profile was used as input to the three-dimensional particle-in-cell code to simulate energy,angular distributions and charge carried by the directional fraction of DLA electrons.The modelling shows good agreement with the experiment and in general a weak dependence of the electron spectra on the plasma profiles,which contain a density up-ramp and a region of near-critical electron density.This explains the high DLA stability in pre-ionized foams,which is important for applications.
基金
funded by the German Ministry for Education and Research(BMBF)under contract No.05P21SJFA2
the Ministry of Science and Higher Education of the Russian Federation(Agreement No.075-15-2021-1361)
the Czech Ministry of Education,Youth and Sports(Project No.CZ.02.2.69/0.0/0.0/18_053/0016980)
the Grant Agency of the Czech Republic(Grant No.GM23-05027M)。
