Experimental Observation of Plasma Wake-Field Acceleration

Results are reported from an experimental test of the physics of plasma wake-field acceleration performed at the Argonne National Laboratory Advanced Accelerator Test Facility. Megavolt-per-meter plasma wake fields are excited by an intense 21-MeV, multipicosecond bunch of electrons in a plasma of density n(e) = 10 to the 13th/cu cm, and probed by a low-intensity 15-MeV witness pulse with a variable delay time behind the intense bunch. Accelerating and deflecting wake-field measurements are presented, and the results compared to theoretical predictions.