Quasimonoenergetic electron beams from laser wakefield acceleration in pure nitrogen

Abstract

Quasimonoenergetic electron beams with maximum energy >0.5 GeV and 2 mrad divergence have been generated in pure nitrogen gas via wakefield acceleration with 80 TW, 30 fs laser pulses. Long low energy tail features were typically observed due to continuous ionization injection. The measured peak electron energy decreased with the plasma density, agreeing with the predicted scaling for electrons. The experiments showed a threshold electron density of 3×1018cm-3 for self-trapping. Our experiments suggest that pure Nitrogen is a potential candidate gas to achieve GeV monoenergetic electrons using the ionization induced injection scheme for laser wakefield acceleration.

Giga-electronvolt electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

“…Looking at the average of all the maximum peak energies, one can see that the peak energy agrees approximately with the prediction when the plasma density is above 6 × 10 18 cm −3 , below which the measurement starts to deviate from the prediction. This phenomena was observed and reported previously 31 and is attributed to the violation of bubble matching condition which is needed to self guide the laser propagation inside the plasma. However, in relatively high plasma density region, i.e.…”

“…In this paper, we will report the experimental results on the laser wakefield driven electron generation achieved with the 200 TW beamline at the Advanced Laser Light Source (ALLS) facility located at INRS, Varennes 29 , which is a platform developed for high intensity relativistic laser-plasma interaction studies and for laser wakefield acceleration studies 12,[30][31][32] . In the experiment, GeV electrons have been observed with self-injection in relatively high density plasma, on the order of 1 × 10 19 cm −3 , produced by ultra-intense laser pulse interacting with a single-stage gas jet.…”

Generation of high-quality electron beams by ionization injection in a single acceleration stage

“…This case is closer to the case of our previously reported LWFA results in pure nitrogen gas jets which generates long-tail electron beams [32,37] . Therefore, we conclude that, given an unmatched laser-plasma parameter, an optimization of the doped gas concentration seems to be very important to achieve an optimum electron beam quality with very small energy spread.…”

High power guiding and electron acceleration in pure N5+ plasma channels

“…The low energy tail is commonly observed in ionization injection from continuous injection throughout the acceleration process 10,11 . For the flat channel, 040004-3 however, we were not able to measure the electron energy due to unstable beam pointing through the magnetic spectrometer.…”