2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/173830Prolific electron-positron pair production is possible at laser intensities approaching 10^{24} W/cm^2 at a wavelength of 1 micron. An analysis of electron trajectories and interactions at the nodes (B=0) of two counter-propagating, circularly polarised laser beams shows that a cascade of gamma-rays and pairs develops. The geometry is generalised qualitatively to linear polarisation and laser beams incident on a solid target.4 pages, 1 figure, minor revisions, accepted for publication in Physical Review LettersHigh Energy Physics - Phenomenologytext