Nonlaminar multicomponent models for electron flow in positive polarity multigap accelerators

Abstract

Electron flow in multigap positive-polarity inductive accelerators is studied by numerical simulation and modeling. The objective of this work is to determine the operating principles of the electron flow such that an optimally efficient design of such machines can be achieved for intense ion beam generation. Because the electrons emitted in different gaps have different energies and canonical momenta, the theory of single-component magnetic insulation has to be extended in order to describe such multicomponent electron flows. A two-dimensional electromagnetic particle-in-cell code is used to simulate multicomponent electron flow in multigap accelerators with two, three, and four gaps. Observations from these simulations lead to new one-dimensional, time-independent models for these flows that incorporate the time-averaged effects of diamagnetic electron vortices. Equivalent circuits are constructed for simulated accelerators using voltage–current relations predicted by the models. These circuit models are incorporated into a software package to aid in the design of multigap inductive accelerators.