This article presents the results of a study on transportation of a pulse ion beam of gigawatt power. This beam is formed by a self-magnetically insulated diode with an explosive-emission cathode. The experiments have been performed using the TEMP-4M pulsed ion accelerator configured in double-pulse formation mode with the first negative pulse (300-500 ns, 100-150 kV), followed by the second positive pulse (150 ns, 250-300 kV). To increase the effectiveness of ion beam focusing, a metal shield is installed on a grounded electrode. Investigations are performed using a strip focusing diode, a cone diode, and a spiral diode with metal shields of different constructions. We observed that the beam diameter at the focus decreases from 60 mm (without shield) to 40-42 mm (with a shield), which leads to an increase in the energy density by a factor of 1.5-2 being 4-5 J/cm2 at the focus. We analyzed different mechanisms for ion trajectories deviation from an ideal one: Coulomb repulsion due to incomplete space charge neutralization, influence of electromagnetic fields, etc. It is found that for a strip focusing diode the concentration of low-energy electrons accompanying the ion beam exceeds the concentration of ions by 1.3-1.5 times. The use of a metal shield improves the transportation properties of the ion beam by keeping neutralizing electrons within the beam volume which ensures its space charge neutralization during the transport.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering