Detailed dynamics of electron beams self-trapped and accelerated in a self-modulated laser wakefield

Abstract

, "Detailed dynamics of electron beams self-trapped and accelerated in a self-modulated laser wakefield" (1999 The electron beam generated in a self-modulated laser-wakefield accelerator is characterized in detail. A transverse normalized emittance of 0.06 mm mrad, the lowest ever for an electron injector, was measured for 2 MeV electrons. The electron beam was observed to have a multicomponent beam profile and energy distribution. The latter also undergoes discrete transitions as the laser power or plasma density is varied. In addition, dark spots that form regular modes were observed in the electron beam profile. These features are explained by analysis and test particle simulations of electron dynamics during acceleration in a three-dimensional plasma wakefield.

Optical Deflection and Temporal Characterization of an Ultrafast Laser-Produced Electron Beam

“…The beam depicted has an angular divergence of 1 deg. The energy distribution of the beam is exponential with an effective energy of 520 keV as measured by us and in agreement with previous observations [1]. The angular profile and energy distribution of the beam depend sensitively on the plasma density and laser intensity.…”

“…We have assumed a uniform energy distribution across the cross section of the beam, an assumption which is reasonable for the lower energy electrons relevant here and has been verified experimentally [1]. The unperturbed angular function is experimentally determined from single beam measurements.…”

“…When a 0 1, the electric field of the light pulse is large enough that electrons oscillate at relativistic velocities. One application that has received considerable recent attention is the study of laser-accelerated electron beams, which-on account of their low transverse emittance [1,2]-hold promise as injectors for both conventional accelerators and for all optically driven x-ray sources based on nonlinear Thomson scattering [3][4][5].…”

Developments in relativistic nonlinear optics

“…It has been attributed to catastrophic wave-breaking of a relativistic Raman forward scattered plasma wave, and to wavebreaking of slower velocity Raman backscattered waves in both experiment and theory. A two-temperature distribution in the electron energy spectrum was observed [7] to accompany a multi-component spatial profile of the electron beam. In this case, electrons in the low energy range were observed to undergo an abrupt change in temperature, coinciding with the onset of extension of the laser channel due to selfguiding of the laser pulse, when the laser power or plasma density was varied.…”

Trapping, compression, and acceleration of an electron bunch in the nonlinear laser wakefield

“…which formally coincides with the one-dimensional integral of motion (3) [14,26,27]. Electrons can be trapped in the region where wakefield is both accelerating and focusing.…”