Meirielen Caetano de Sousa

Project title:  Electron acceleration by surface plasma waves

Host Institution: École Polytechnique (l’X)

Host Supervisor: Prof. Michèle Raynaud

Co-host Institution: École Polytechnique Fédérale de Lausanne (EPFL)

Co-host Supervisor: Prof. Stephan Brunner

Summary project: The interaction of a laser pulse with an over-dense plasma can be used to excite surface plasma waves (SPWs) on the vacuum-plasma interface. These SPWs accelerate electrons towards relativistic velocities, forming a collimated beam with total charge that can be an order of magnitude higher than that produced by the wakefield mechanism. The SPW acceleration mechanism has a great potential for use in important new applications, including improved laser-based radiation sources. However, open questions persist on SPWs in the high fields regime, related to nonlinear and relativistic effects, in order to improve acceleration. In this context, EASPW aims to enhance the control and acceleration of relativistic electrons by SPWs. A novel approach is proposed based on the analysis of the nonlinear dynamics of relativistic electrons accelerated by SPWs. I will investigate the conditions that trigger chaotic behavior and how it relates to the width of the energy spectrum of electron beams. By applying methods of chaos control, I will suggest a way to improve acceleration and produce beams with narrow, monochromatic, energy spectra. A supplementary control parameter can be given by a stationary magnetic field at the surface. I will analyze the effects produced by this external field, and the conditions for which it enhances electron acceleration. Theoretical analyses will be supported by particle-in-cell (PIC) simulations. EASPW approach is completely innovative. The combination of the new theoretical approach proposed with numerical simulations, up to dimensioning of experiments, will enable an accurate characterization and the improvement of electron acceleration by SPWs.