Abstract
A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. The capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.
Highlights
Few μm and a temporal resolution of as small as a few fs is necessary
We propose a new method of using a femtosecond relativistic electron probe (FREP) to directly map out the plasma based wakefield structure
We first show the concept through PIC simulations using the code OSIRIS28 where the wakes are probed by an ideal electron beam, i.e., with zero energy spread, zero emittance, flat-top current profile and very short pulse length (6.8 fs, limited by the grid size of the simulation box)
Summary
Few μm and a temporal resolution of as small as a few fs is necessary These rigorous constraints can be met if a few fs long, relativistic electron bunch is used as a probe. Such a probe can in principle be generated from a laser wakefield accelerator (LWFA)[27]. We propose a new method of using a femtosecond relativistic electron probe (FREP) to directly map out the plasma based wakefield structure. The qualitative reconstruction of a nonlinear wake is presented. As an example of potential applications of this new tool, imaging of the downramp injection in a nonlinear wake using FREP is presented
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
