2-D fluid simulation of a rigid relativistic electron beam driven wakefield in a cold plasma

TL;DR

This paper uses 2-D fluid simulations to study wakefield behavior driven by relativistic electron beams in cold plasma, showing good agreement with previous models and experimental results, and analyzing electron acceleration outcomes.

Contribution

It demonstrates the effectiveness of 2-D fluid simulations in modeling relativistic beam-driven wakefields and reproduces key features observed in prior 1-D and PIC studies.

Findings

Good agreement with 1-D results for large transverse beam dimensions.

Recovery of blow-out structures in overdense, narrow beams.

Maximum electron energy gain of 2.6 GeV in 10 cm plasma, doubled near the axis.

Abstract

Fluid simulations, which are considerably simpler and faster, have been employed to study the behavior of the wakefield driven by a relativistic rigid beam in a 2-D cold plasma. When the transverse dimensions of the beam are chosen to be much larger than its longitudinal extent, a good agreement with our previous 1-D results [\textcolor{red}{\it Physics of Plasmas 22, 073109 (2015)}] are observed for both under-dense and over-dense beams. When the beam is overdense and its transverse extent is smaller or close to the longitudinal extension, the 2-D blow-out structure, observed in PIC simulations and analytically modeled by Lu et al. [\textcolor{red}{\it Phys. Rev. Lett., 96, 165002 (2006)}] are recovered. For quantitative assessment of particle acceleration in such a wake potential structure test electrons are employed. It is shown that the maximum energy gained by the test electrons placed at the back of the driver beam of energy $\sim 28.5$ GeV, reaches up to $2.6$ GeV in a 10 cm long plasma. These observations are consistent with the experimental results presented in ref. [\textcolor{red}{\it Phys. Rev. Lett. 95, 054802 (2005)}]. It is also demonstrated that the energy gained by the test electrons get doubled ($\sim 5.2$ GeV) when the test particles are placed near the axis at the end of the first blowout structure.