Beam optics in inertial electrostatic confinement fusion

We study the transport of ions and electrons near the cathode of the inertial electrostatic confinement fusion that is expected to be a portable neutron source. We carry out a PIC particle simulation in order to obtain the self-consistent electrostatic potential and the transparency of the cathode for the accelerated ions. The transparency is shown to be much less than a geometrical transparency and possesses a strong dependence on the energy of ions. The increase of the applied voltage results in larger neutron production due to increased fusion cross section and also increased ion current by the improved transparency.