The effect of ion density in a plasma channel on the profile of bubble rear is investigated theoretically. The wakefield contraction and the steepness of the bubble rear depend on the ratio of ions in a uniform plasma to those in a channel. With the decreasing of ion density in the channel, the bubble length becomes shorter and its bubble rear is steeper. The electron dynamics show that a typical electron can oscillate between the upper and lower boundaries of the channel, not like the betatron oscillation around the on-axis in homogeneous plasma. These results are verified by two-dimensional particle-in-cell simulations. By optimizing the radius of the hollow plasma channel, the front part of a self-injected electron bunch can be reflected back into the channel by the transverse focusing force, while its rear part will escape from the channel. The electric field is transversely uniform and has longitudinally plateau in the regime of self-injected electron bunch, which allows for monoenergetic acceleration.

Date Published: 29 March 2019
PDF: 10 pages
Proc. SPIE 11046, Fifth International Symposium on Laser Interaction with Matter, 1104613 (29 March 2019); doi: 10.1117/12.2524465

Published in SPIE Proceedings Vol. 11046:
Fifth International Symposium on Laser Interaction with Matter
YiJun Zhao, Editor(s)