Different phases of the fast magnetosonic (fms) pulse current sheet interaction in a large system. The pulse propagates upwards into the upstream. We display the current density (bottom panel), as well as out-of-plane electric field of the emerging fast wave signal (top panel). The compression triggers reconnection in the otherwise stable current sheet. Small plasmoids appear and merge to form hierarchically larger ones under the emission of a firework of high-frequency fms waves.