Electron energy increase in a laser wakefield accelerator using longitudinally shaped 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 by more than 50%, from 174.8 +/- 1.3 MeV to 262 +/- 9.7 MeV and the maximum peak energy from 182.1 MeV to 363.1 MeV. The divergence follows closely the change of mean energy and decreases from 58.95 +/- 0.45 mrad to 12.63 +/- 1.17 mrad along the horizontal axis and from 35.23 +/- 0.27 mrad to 8.26 +/- 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.
Cite
@article{arxiv.1809.02899,
title = {Electron energy increase in a laser wakefield accelerator using longitudinally shaped plasma density profiles},
author = {Constantin Aniculaesei and Vishwa Bandhu Pathak and Hyung Taek Kim and Kyung Hwan Oh and Byung Ju Yoo and Enrico Brunetti and Yong Ha Jang and Calin Ioan Hojbota and Junghun Shin and Jeong Ho Jeon and Seongha Cho and Myung Hoon Cho and Jae Hee Sung and Seong Ku Lee and Björn Manuel Hegelich and Chang Hee Nam},
journal= {arXiv preprint arXiv:1809.02899},
year = {2019}
}