Extreme light infrastructure (ELI): Physics and lasers at the ultra-intense frontier

ELI has been put on the European Roadmap for Research infrastructures by the European Strategy Forum on Research Infrastructures (ESFRI). It will be the first Paneuropean Infrastructure utilizing an ultra-intense laser with a peak-power of 200 PW for interaction experiments with electric field strength well above the PV/m (10
¹⁵
V/m ). With the high focused intensity (above 4 × 10
²⁴
W/cm
²
) it will be possible to enter the ultra-relativistic regime when protons are accelerated to nearly the speed of light at a distance in the order of the wavelength of the driving extreme light. Fundamental physics phenomena can be investigated for the first time including nonlinear vacuum interaction and pair generation. ELI intermediate beam lines with peak-powers in the few PW range but higher repetition rates (10 Hz) will enable scientific and societal including medical applications based on laser particle acceleration (proton therapy) and x-ray generation. The photonuclear facility will explore nuclei with hard x-ray and gamma-ray photons produced by high intensity interaction with matter. The Attosecond science laser driver with its high repetition rate (1 kHz) and high average power (>1 kW, 5-10fs) opens the way to ultrafast investigations in different scientific and technological areas with time resolutions in the Attosecond and may by even faster (zeptosecond) time domains using very brilliant VUV-light and x-rays generated by harmonics from gases or solids.