Research is centered on exploring the physics of charged particle beams at the extreme frontier of intensity. For many applications the intensity or luminosity frontier is as important as the energy frontier. Examples of such applications include high-luminosity colliders, spallation neutron sources and X-ray free electron lasers and related intense light sources, high-average-power free electron lasers, and future heavy ion-driven inertial fusion concepts. The group operates two world-class research facilities: the University of Maryland Electron Ring (UMER), and the Laboratory for Photocathode Research.. In addition, group members participate in experiments at a number of research laboratories worldwide. Some members of this group participate in the Center for Applied Electromagnetics (AppEl). This group graduates approximately two PhD students per year.