Physics Commons^™

Electron Self-Injection Into An Evolving Plasma Bubble: Quasi-Monoenergetic Laser-Plasma Acceleration In The Blowout Regime, Serguei Y. Kalmykov, Arnaud Beck, Sunghwan A. Yi, Vladimir N. Khudik, Michael C. Downer, Erik Lefebvre, Bradley A. Shadwick, Donald P. Umstadter

Donald P. Umstadter

An electron density bubble driven in a rarefied uniform plasma by a slowly evolving laser pulse goes through periods of adiabatically slow expansions and contractions. Bubble expansion causes robust self-injection of initially quiescent plasma electrons, whereas stabilization and contraction terminate self-injection thus limiting injected charge; concomitant phase space rotation reduces the bunch energy spread. In regimes relevant to experiments with hundred terawatt- to petawatt-class lasers, bubble dynamics and, hence, the self-injection process are governed primarily by the driver evolution. Collective transverse fields of the trapped electron bunch reduce the accelerating gradient and slow down phase space rotation. Bubble expansion followed …