Experiments with combined laser and gamma beams at ELI-NP

We briefly describe in this paper some of the proposed experiments for the E7 and E4 experimental areas at ELI-NP. Our experiments tackle fundamental problems in physics, taking advantage of the unique configuration (high intensity laser plus gamma/electron beam) at ELI-NP in Magurele, Romania. We discuss the gradual approach from a complexity point of view, from “commissioning” or “day 1” experiments to the ones needing key results from the previously proposed ones and R&D advances in fields such as laser wakefield acceleration of electrons, extremely high vacuum or synchronization at tens of femtoseconds level between the pulses. The high repetition rate of the ultra-short laser pulses at E4 is a key factor for the success of the proposed experiment.