Physical Processes in Compensated Negative-Ion Beams and Related Beam   Transport Problems
  This paper reviews resent theoretical and experimental research on physical processes in compensated negative-ion beams. A previous review was published by one of the authors in Ref. [1]. The present paper summarizes the new results of numerical calculations of the stationary electric field in negative-ion beams, and the resent results of experimental studies of suppression of ion-ion instability at low gas pressures. As in Ref. [1], the review addresses the following three main issues of the physics of compensated beams: 1) Spatial charge compensation in steady beams; 2) Dynamic decompensation of spatial charge, which occurs as a result of beam current modulation due to plasma instabilities in the ion source; 3) Collective processes. The results presented in this review enable one to determine how non-compensated spatial charge, nonresonant oscillations of the beam current, and collective oscillations of the ion-beam plasma influence the propagation properties of the beam. With this information, one can determine the optimal ion transportation parameters. 
I.A.Soloshenko (Institute of Physics, National Academy of Sciences,   Ukraine, Kiev), V.N.Gorshkov (CNLS and Theoretical Div...