CERN Accelerating science

Article
Title	Characteristics of betatron radiation in AWAKE Run 2 experiment
Author(s)	Liang, Linbo (Manchester U. ; SLAC, SSRL) ; Saberi, Hossein (Manchester U. ; SLAC, SSRL) ; Xia, Guoxing (Manchester U. ; SLAC, SSRL) ; Farmer, John Patrick (CERN ; Munich, Max Planck Inst.) ; Pukhov, Alexander (Heinrich Heine U., Dusseldorf)
Publication	2023
Number of pages	17
In:	J. Plasma Phys. 89 (2023) 965890301
DOI	10.1017/s0022377823000491
Subject category	Accelerators and Storage Rings
Accelerator/Facility, Experiment	CERN AWAKE
Abstract	The oscillating relativistic electrons in the accelerating/focusing wakefields of plasma accelerators emit electromagnetic radiation known as betatron radiation (BR). The proton-driven plasma wakefield acceleration has been demonstrated in the Advanced Wakefield Experiment (AWAKE) at CERN; however, its accompanying radiation emission is less explored compared with those in the laser- and electron beam-driven plasma accelerators. In this paper, a detailed simulation study of BR in the AWAKE is presented. Considering the new set-up of the AWAKE Run 2 (2021–), the radiation emission from both the witness electron beam and the seeding electron beam is investigated using particle-in-cell simulations. The influence of radial size mismatch and misaligned off-axis injection on the witness beam dynamics, as well as the spectral features of the relevant BR are studied. These non-ideal electron injections are likely to occur in experiment. The proton self-modulation stage is also investigated with a close look at the seeding electron beam dynamics and its BR. As a footprint of the emitting particles, BR can provide valuable information about the beam dynamics. Some practical challenges to implement the betatron diagnostic in the AWAKE Run 2 experiment are also addressed.
Copyright/License	publication: (License: CC-BY-4.0) © 2023-2025 The Author(s)

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