Transformer-ratio optimization in nonlinearly driven hollow plasma channels

Abstract

Acceleration to high energies in electron-driven wakefield accelerators requires a carefully tailored drive beam. High driver currents can, however, modify the accelerating structure response, shifting the optimal driver profile. In this work we present a simple model to describe this nonlinear beamloading in hollow plasma channels. The increase in channel radius and the generation of a return current in the bulk plasma act to modify the resonant frequency and accelerator loss factor. Modeling these effects allows the optimal driver profile to be calculated.