The positive space charge lens for focusing and manipulating high-current beams of negatively charged particles (review)

Abstract

We describe a new approach for creation of effective axially symmetric plasma tools for focusing and manipulating high-current negatively charged particles beams, electrons and negative ions. This approach is based on the fundamental plasma optical concept of magnetic and electrostatic insulation of electrons, and non-magnetized positive ions providing controlled uncompensated positive space charge cloud formation. The recent advances in creation of negative ion sources lead to the problem of elaboration and creation of focusing tools that are capable of manipulating high-current negative ion beams. We present results of experimental investigations of the positive space charge electrostatic plasma lens based on the idea of electron electrostatic insulation first proposed for these goals. Also, we describe novel experimental, theoretical and computer simulation results of the application of electron magnetic insulation concept for generating the stable cloud of positive space charge by focusing the converging flow of heavy ions produced by circular accelerator with closed electron drift onto the axis.