Particle-in-cell simulations of a planar magnetically insulated ion diode for surface modification of materials

Intense pulsed ion beam (IPIB) techniques have been widely investigated in the field of surface modification of materials over the past few years. Most IPIB sources for this purpose consist of a magnetically insulated diode (MID). To study the characteristics of this type of IPIB source, simulations of the time-dependent characteristics of a planar MID have been carried out, based upon a plasma explosive emission model, by using the electromagnetic particle-in-cell MAGIC code. From these numerical simulations, the behavior of the charged particles in the gap of diodes and the distribution of ion current density are derived. The effects of the external insulating magnetic field and the diode voltage on the electron and ion flow are presented; meanwhile, the influences of the magnetic field on the charged particle distribution and of the virtual cathode on the neutralization of ion flow are emphasized.