High quality electron beam generation in a proton-driven hollow plasma wakefield accelerator

Simulations of proton-driven plasma wakefield accelerators have demonstrated substantially higher accelerating gradients compared to conventional accelerators and the viability of accelerating electrons to the energy frontier in a single plasma stage. However, due to the strong intrinsic transverse fields varying both radially and in time, the witness beam quality is still far from suitable for practical application in future colliders. Here we demonstrate efficient acceleration of electrons in proton-driven wakefields in a hollow plasma channel. In this regime, the witness bunch is positioned in the region with a strong accelerating field, free from plasma electrons and ions. We show that the electron beam carrying the charge of about 10% of 1 TeV proton driver charge can be accelerated to 0.6 TeV with preserved normalized emittance in a single channel of 700 m. This high quality and high charge beam may pave the way for the development of future plasma-based energy frontier colliders.Comment: 10 pages, 7 figure

Proposition ou suite de mots ? (Le problème de la prédication dans la linguistique soviétique des années 40).

Proton-driven plasma wakefield acceleration has been demonstrated in simulations to be capable of accelerating particles to the energy frontier in a single stage, but its potential is hindered by the fact that currently available proton bunches are orders of magnitude longer than the plasma wavelength. Fortunately, proton micro-bunching allows driving plasma waves resonantly. In this paper, we propose using a hollow plasma channel for multiple proton bunch driven plasma wakefield acceleration and demonstrate that it enables the operation in the nonlinear regime and resonant excitation of strong plasma waves. This new regime also involves beneficial features of hollow channels for the accelerated beam (such as emittance preservation and uniform accelerating field) and long buckets of stable deceleration for the drive beam. The regime is attained at a proper ratio among plasma skin depth, driver radius, hollow channel radius, and micro-bunch period.Comment: 15 pages, 9 figure