Computer simulations (without actual experiments) of improved advanced techniques to produce a "shower" of electrons and positrons by hitting a metal target wit

Computer simulations (without actual experiments) of improved advanced techniques to produce a "shower" of electrons and positrons by hitting a metal target with a laser, which are then accelerated and confined with a second laser driving plasma waves. The figures in the article, with lasers reflected by mirrors and particle beams going through the mirrors, suggest a very small but decently powerful single stage accelerator; using this technique as a building block for a large accelerrator isn't discussed.