Scheme for proton-driven plasma-wakefield acceleration of positively charged particles in a hollow plasma channel

Longqing Yi,Xueyan Zhao,Wenpeng Wang,Liangliang Ji,Baifei Shen,Zhizhan Xu,Jiancai Xu,Yahong Yu,Xiaofeng Wang,Konstantin Lotov,Yin Shi,Lingang Zhang,Tongjun Xu,Xiaomei Zhang

doi:10.1103/physrevstab.16.071301

Abstract

A new scheme for accelerating positively charged particles in a plasma wakefield accelerator is proposed. If the proton drive beam propagates in a hollow plasma channel, and the beam radius is of order of the channel width, the space charge force of the driver causes charge separation at the channel wall, which helps to focus the positively charged witness bunch propagating along the beam axis. In the channel, the acceleration buckets for positively charged particles are much larger than in the blowout regime of the uniform plasma, and stable acceleration over long distances is possible. In addition, phasing of the witness with respect to the wave can be tuned by changing the radius of the channel to ensure the acceleration is optimal. Two dimensional simulations suggest that, for proton drivers likely available in future, positively charged particles can be stably accelerated over 1 km with the average acceleration gradient of 1.3 GeV/m.

Highlights

The development of conventional accelerators has brought us to the brink of a new era of particle physics
If the proton drive beam propagates in a hollow plasma channel, and the beam radius is of order of the channel width, the space charge force of the driver causes charge separation at the channel wall, which helps to focus the positively charged witness bunch propagating along the beam axis
High quality proton beams as energetic as 7 TeV are available in Large Hadron Collider (LHC) at European Center for Particle Physics (CERN)

Summary

Published by the American Physical Society

Plasma-wakefield acceleration in channels is not free from transformer ratio limit [22] stating that the energy gain of the witness beam cannot in practice exceed roughly 2 times the driver energy. Since protons can carry much more energy than electrons in nowadays accelerators, they have the potential to excite the wakefield over a long distance and accelerate a witness beam to very high energies [23]. A TeV proton beam is used as the driver to generate strong plasma wakefields, which in principle enables a witness bunch to gain TeV-range energies in a single stage of acceleration.

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Findings

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