Proposals for future high-energy accelerators are characterized by demands for increasingly intense and energetic beams. The classical operation of high-current accelerators is severely constrained by collective electrodynamic phenomena, such as problems related to space-charge, to high-current flow, to beamstrahlung and pair production. These detrimental electrodynamic effects dominate the dynamic s and the collision interactions of high-intensity beams. With the introduction of soft space-charge and current compensation techniques utilizing low- to medium-energy lepton beams with charge polari ty opposite to that of the beams to be neutralized, all electromagnetic high-intensity limitations may be removed. The application of beam compensation is proposed for various sections of different ty pes of classical accelerator systems, such as for ion sources and the low-energy beam transport sections of ion linacs, for the crossing points of circular and linear colliders and for the final focii of ion beam fusion drivers. The design and the operation of partially compensated accelerators becomes much more comfortable and design goals can be reached more easily without any significant electro magnetic perturbation. The ingredients of neutralization technology low-energy electron and positron beams are state-of-the-art and, as such, applicable today. Several methods of smooth beam compe nsation can be identified and must be studied and selected for each specific case. Practical experience has to be gained in dedicated pilot experiments
