Characterization of electron beams produced by ultrashort (30 fs) laser pulses

Abstract

International audienceDetailed measurements of electron spectra and charges from the interaction of 10 Hz, 600 mJ laser pulses in the relativistic regime with a gas jet have been done over a wide range of intensities (10^18–2×10^19 W/cm^2) and electron densities (1.5×10^18–1.5×10^20 cm^−3), from the “classical laser wakefield regime” to the “self-modulated laser wakefield” regime. In the best case the maximum electron energy reaches 70 MeV. It increases at lower electron densities and higher laser intensities. A total charge of 8 nC was measured. The presented simulation results indicate that the electrons are accelerated mainly by relativistic plasma waves, and, to some extent, by direct laser acceleration

Electron self-injection into an evolving plasma bubble: Quasi-monoenergetic laser-plasma acceleration in the blowout regime

“…The quasistatic nature of the bulk plasma response makes it possible to elucidate the physics of self-injection using a conceptually simple and computationally efficient toolbox: a fully relativistic 3D particle tracking module 24,39 built into the cylindrically symmetric time-averaged quasistatic PIC code WAKE. 38 WAKE models the laser pulse propagation using an extended paraxial solver.…”

“…In particular, it takes into account the interaction of test electrons with the nonaveraged, linearly polarized laser field with nonparaxial corrections. 39,42 To capture the laser pulse interaction with nonquasistatic background electrons (and thus to model self-injection into nonstationary quasistatic wake fields), a group of quiescent test electrons is placed before the laser pulse at each time step. In this way, electron self-injection associated with bubble and driver evolution is separated from the effects brought about by the collective fields of the trapped electron bunch, i.e., from effects due to beam loading.…”

Production of a keV X-Ray Beam from Synchrotron Radiation in Relativistic Laser-Plasma Interaction

“…At larger densities, the x-ray signal drops down and a plateau is reached. For these experimental conditions, the laser must first be modulated to create high amplitude plasma waves [20] and much higher laser intensity is needed.…”

Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator

“…At present, thermionic and photoemission based electron sources are widely used [25]; however, plasma based electron sources are an active topic of research due to their potential to produce high current and low emittance electron bunches [67,23,17,3,40,44,49,16]. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake [58] and accelerate them to high energies.…”