Publications Details

Particle-in-cell simulations of electron beam control using an inductive current divider

Swanekamp, S.B.; Angus, J.R.; Cooperstein, G.; Ottinger, P.F.; Richardson, A.S.; Schumer, J.W.; Weber, B.V.

Kinetic, time-dependent, electromagnetic, particle-in-cell simulations of the inductive current divider are presented. The inductive current divider is a passive method for controlling the trajectory of an intense, hollow electron beam using a vacuum structure that inductively splits the beam’s return current. The current divider concept was proposed and studied theoretically in a previous publication [Phys. Plasmas 22, 023107 (2015)] A central post carries a portion of the return current (I₁) while the outer conductor carries the remainder (I₂) with the injected beam current given by I_b=I₁+I₂. The simulations are in agreement with the theory which predicts that the total force on the beam trajectory is proportional to (I₂-I₁) and the force on the beam envelope is proportional to I_b. For a fixed central post, the beam trajectory is controlled by varying the outer conductor radius which changes the inductance in the return-current path. The simulations show that the beam emittance is approximately constant as the beam propagates through the current divider to the target. As a result, independent control over both the current density and the beam angle at the target is possible by choosing the appropriate return-current geometry.