Ponderomotive effects on charged particle beam limiting current

The physical mechanism responsible for the space-charge-limiting current in a wave cavity and in the presence of electromagnetic fields is addressed. It is found that the ponderomotive energy alters radically the buildup of beam electrostatic energy. As a consequence, the limiting current can be greatly decreased or enhanced depending on whether the ponderomotive energy is positive or negative, respectively. This effect could be observed experimentally, and it is anticipated to have important practical consequences for present high-current particle beam experiments