Abstract A new generation of high power laser facilities will provide laser pulses with extremely high powers of 10 Peta-Watt (PW) and even 100 PW, capable of reaching 1023 W/cm2 in the laser focus. These ultrahigh intensities are nevertheless lower than the Schwinger intensity IS = 2.3x1029 W/cm2 at which the theory of Quantum Electrodynamics (QED) predicts that a large part of the energy of the laser-photons will be transformed to hard gamma-ray photons and even to mass, via electron-positron pair production. To enable the investigation of this physics at the intensities achievable with the next generation of high power laser facilities, an approach involving the interaction of two colliding PW laser pulses
is being adopted. Theoretical simulations predict strong QED effects with colliding laser pulses of ≥10 PW focused to intensities ≥1022 W/cm2.
Key words: Quantum Electrodynamics; Colliding PW Laser Pulses; Peta-Watt Laser Facilities; Electron-Positron Pairs; Nonlinear Breit-Wheeler process;
