Electron energy increase in a laser wakefield accelerator using up-ramp plasma density profiles.

ABSTRACT: The phase velocity of the wakefield of a laser wakefield accelerator can, theoretically, be manipulated by shaping the longitudinal plasma density profile, thus controlling the parameters of the generated electron beam. We present an experimental method where using a series of shaped longitudinal plasma density profiles we increased the mean electron peak energy more than 50%, from 175?±?1?MeV to 262?±?10?MeV and the maximum peak energy from 182?MeV to 363?MeV. The divergence follows closely the change of mean energy and decreases from 58.9?±?0.45 mrad to 12.6?±?1.2 mrad along the horizontal axis and from 35?±?0.3 mrad to 8.3?±?0.69 mrad along the vertical axis. Particle-in-cell simulations show that a ramp in a plasma density profile can affect the evolution of the wakefield, thus qualitatively confirming the experimental results. The presented method can increase the electron energy for a fixed laser power and at the same time offer an energy tunable source of electrons.

SUBMITTER: Aniculaesei C 

PROVIDER: S-EPMC6677811 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature