Features of focusing of a high-intensity pulsed ion beam formed by a diode with a passive anode

The results of investigating the focusing of a high-power ion beam, which is formed by a diode with a semicylindrical geometry and a passive anode, are presented. Two types of focusing diodes were investigated: with external magnetic insulation (one-pulse mode) and self-magnetic insulation of electrons (twopulse mode). Measurements of the energy-density distribution of the ion beam and the ion-current density were performed. It was found that when the diode operates in the two-pulse mode, the region of the maximum ion-beam energy density in the focal plane is displaced relative to the region of the maximum ion-current density by 5–10 mm. It is shown that the effect of a displacement of the focal spot with the maximum energy density is determined by the presence of a large number of accelerated neutral atoms in the ion beam. These atoms are produced as a result of the ion charge-exchange process in the anode–cathode gap of the ion diode during its operation in the two-pulse mode.