Gas-dynamic density downramp injection in a beam-driven plasma wakefield accelerator
Jurjen Couperus Cabadağ, Richard Pausch, Susanne Schöbel, Michael Bußmann, Yen-Yu Chang, S. Corde, Alexander Debus, Hao Ding, A. Döpp, F. Foerster, M. Gilljohann, Florian Haberstroh, T. Heinemann, B. Hidding, S. Karsch, Alexander Koehler, Olena Kononenko, A. Knetsch, Thomas Kurz, A. Martínez de la Ossa, Alastair Nutter, Gaurav Raj, Klaus Steiniger, U. Schramm, Patrick Ufer, Arie Irman
Abstract
We present the experimental demonstration of density downramp injection at a gas-dynamic shock in a beamdriven plasma accelerator. The ultrashort driver electron beam with a peak-current exceeding 10 kA allows operation in the blowout regime and enables injection of electron witness bunches at gentle density ramps, i.e., longer than the plasma wavelength, which nurtures prospects for ultralow bunch emittance. By precision control over the position of injection we show that these bunches can be energy-tuned in acceleration gradients of near 120 GV m -1 .