Injection induced by coaxial laser interference in laser wakefield accelerators

Abstract

We propose a new injection scheme that can generate electron beams with simultaneously a few permille energy spread, submillimeter milliradian emittance, and more than a 100 pC charge in laser wakefield accelerators. In this scheme, a relatively loosely focused laser pulse drives the plasma wakefield, and a tightly focused laser pulse with similar intensity triggers an interference ring pattern that creates onion-like multisheaths in the plasma wakefield. Owing to the change in wavefront curvature after the focal position of the tightly focused laser, the innermost sheath of the wakefield expands, which slows down the effective phase velocity of the wakefield and triggers injection of plasma electrons. Both quasicylindrical and fully three-dimensional particle-in-cell simulations confirm the generation of beams with the above mentioned properties.

Divergence angle consideration in energy spread measurement for high-quality relativistic electron beam in laser wakefield acceleration

“…[8] In order to achieve the quality of electron beam equivalent to that of conventional accelerators, a lower E S is required, under the constraint of the Q being limited by the beam loading effect. [1] The energy spread is defined as the ratio of the energy width at half maximum of the energy spectrum (δ E) to the energy at the peak [10] (E S = (δ E/E max ) × 100%). Researchers are committed to pursuing lower energy spread in theory [10][11][12] and in experiment.…”

“…[1] The energy spread is defined as the ratio of the energy width at half maximum of the energy spectrum (δ E) to the energy at the peak [10] (E S = (δ E/E max ) × 100%). Researchers are committed to pursuing lower energy spread in theory [10][11][12] and in experiment. [3,[13][14][15][16][17][18][19][20][21][22][23] As a consequence, precise measurement of energy spread becomes particularly important.…”

Generation of polarized electron beams through self-injection in the interaction of a laser with a pre-polarized plasma

“…A variety of mechanisms has been proposed to control the electron beams properties which are comparable with those from conventional particle accelerators, such as energy spectra [3][4][5][6][7] , controllability [8] , stability [9,10] , beam emittance [11,12] and beam energy [13] . Many efforts have been made with controllable injection mechanisms to improve the electron beam quality, such as density-transition injection [15,16] , ionization-induced injection [17] , or colliding-pulse injection [18] . However, the control of electron beam polarization has not been investigated thoroughly.…”