Near-threshold electron injection in the laser–plasma wakefield accelerator leading to femtosecond bunches

Islam, M.R. et al. (2015) Near-threshold electron injection in the laser–plasma wakefield accelerator leading to femtosecond bunches. New Journal of Physics, 17(9), 093033. (doi: 10.1088/1367-2630/17/9/093033)

123282.pdf - Published Version
Available under License Creative Commons Attribution.



The laser–plasma wakefield accelerator is a compact source of high brightness, ultra-short duration electron bunches. Self-injection occurs when electrons from the background plasma gain sufficient momentum at the back of the bubble-shaped accelerating structure to experience sustained acceleration. The shortest duration and highest brightness electron bunches result from self-injection close to the threshold for injection. Here we show that in this case injection is due to the localized charge density build-up in the sheath crossing region at the rear of the bubble, which has the effect of increasing the accelerating potential to above a critical value. Bunch duration is determined by the dwell time above this critical value, which explains why single or multiple ultra-short electron bunches with little dark current are formed in the first bubble. We confirm experimentally, using coherent optical transition radiation measurements, that single or multiple bunches with femtosecond duration and peak currents of several kiloAmpere, and femtosecond intervals between bunches, emerge from the accelerator.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Shanks, Dr Richard
Authors: Islam, M.R., Brunetti, E., Shanks, R.P., Ersfeld, B., Issac, R.C., Cipiccia, S., Anania, M.P., Welsh, G.H., Wiggins, S.M., Noble, A., Cairns, R.A., Raj, G., and Jaroszynski, D.A.
Subjects:Q Science > QC Physics
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:New Journal of Physics
Publisher:IOP Publishing
ISSN (Online):1367-2630

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
592571CRITICAL MASS: Collective radiation-beam-plasma interactions at high intensitiesValentine O'SheaEngineering & Physical Sciences Research Council (EPSRC)EP/J018171/1P&A - PHYSICS & ASTRONOMY