  Molecular dynamics simulations, with full Coulomb interaction and
self-consistent field emission, are used to examine mutual space-charge
interactions between beams originating from several emitter areas, in a planar
infinite diode. The simulations allow observation of the trajectory of each
individual electron through the diode gap. Results show that when the
center-to-center spacing between emitters is greater than half of the gap
spacing the emitters are essentially independent. For smaller spacing the
mutual space-charge effect increases rapidly and should not be discounted. A
simple qualitative explanation for this effect is given.
