Compensated ion beams

Ion beams have found wide application in many areas of science and technology, in nuclear physics, in the field of controlled thermonuclear fusion, and for various purposes in technology. At the present time, the currents in ion beams have reached hundreds of amperes in the steady-state regime or hundreds of kiloamperes pulsed. The mutual repulsion of charged particles of the same sign causes ion beams to diverge, even for considerably lower currents, over only a short propagation path length if their space charge is not compensated by charges of opposite sign. Thus, intense ion beams usually exist in the compensated state and constitute a special type of plasma: an ion-beam plasma. The present work presents experimental results obtained at the Institute of Physics of the Academy of Sciences of the Ukrainian SSR and constituting the basis for a new branch of plasma physics: the physics of ion-beam plasma. The work is reviewed under the headings: space-charge compensation of ion beams; collective oscillations in compensated ion beams (electron plasma (Langmuir) oscillations, ion oscillations, instability of a synthesized ion-ion beam, instability of ion beams in a magnetic field); transport and focusing of compensated ion beams. (U.K.)