Particle-in-cell simulations of electron beam control using an inductive current divider
Abstract
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 [Swanekamp et al., 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 Ib = 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 Ib. Independent control over both the current density and the beam angle at the target is possible by choosing the appropriate current-divider geometry. The root-mean-square (RMS) beam emittance (εRMS) varies as the beam propagates through the current divider to the target. For applications where control of the beam trajectory is desired and the current density at the target is similar to the current density at the entrance foil, there is a modest 20% increase in εRMS at the target. For other applications where the beam is pinched to a current density ∼5 times larger at the target, εRMS is 2–3 times larger at the target.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2015
- Source ID
- 10.1063/1.4935893
Entities
People
- A. S. Richardson
- Bruce V. Weber
- Gerald Cooperstein
- J. R. Angus
- J. W. Schumer
- P. F. Ottinger
- S. B. Swanekamp
Organizations
- Office of Naval Research
- United States Naval Research Laboratory