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Title: Improvement of electron beam quality in optical injection schemesusing negative plasma density gradients

Abstract

Enhanced electron trapping using plasma density down ramps as a method for improving the performance of laser injection schemes is proposed and analyzed. A decrease in density implies an increase in plasma wavelength, which can shift a relativistic electron from the defocusing to the focusing region of the accelerating wakefield, and a decrease in wake phase velocity, which lowers the trapping threshold. The specific method of two-pulse colliding pulse injector was examined using a three-dimensional test particle tracking code. A density down-ramp with a change of density on the order of tens of percent over distances greater than the plasma wavelength led to an enhancement of charge by two orders in magnitude or more, up to the limits imposed by beam loading. The accelerated bunches are ultrashort (fraction of the plasma wavelength, e.g., {approx}5 fs), high charge (>20 pC at modest injection laser intensity 10{sup 17} W/cm{sup 2}), with a relative energy spread of a few percent at a mean energy of {approx}25 MeV, and a normalized root-mean square emittance on the order 0.5 mm mrad.

Authors:
; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. Office of High EnergyPhysics
OSTI Identifier:
878708
Report Number(s):
LBNL-58354
R&D Project: 455401; BnR: KA1501020; TRN: US0602438
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Physical Review E
Additional Journal Information:
Journal Volume: 73; Journal Issue: 2pt2; Related Information: Journal Publication Date: 02/2006
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ELECTRON BEAMS; ELECTRONS; FOCUSING; LASERS; PERFORMANCE; PHASE VELOCITY; PLASMA; PLASMA DENSITY; TEST PARTICLES; TRAPPING; WAVELENGTHS; plasma density laser wakefield accelerator

Citation Formats

Fubiani, G., Esarey, E., Schroeder, C.B., and Leemans, W.P. Improvement of electron beam quality in optical injection schemesusing negative plasma density gradients. United States: N. p., 2005. Web.
Fubiani, G., Esarey, E., Schroeder, C.B., & Leemans, W.P. Improvement of electron beam quality in optical injection schemesusing negative plasma density gradients. United States.
Fubiani, G., Esarey, E., Schroeder, C.B., and Leemans, W.P. Tue . "Improvement of electron beam quality in optical injection schemesusing negative plasma density gradients". United States. https://www.osti.gov/servlets/purl/878708.
@article{osti_878708,
title = {Improvement of electron beam quality in optical injection schemesusing negative plasma density gradients},
author = {Fubiani, G. and Esarey, E. and Schroeder, C.B. and Leemans, W.P.},
abstractNote = {Enhanced electron trapping using plasma density down ramps as a method for improving the performance of laser injection schemes is proposed and analyzed. A decrease in density implies an increase in plasma wavelength, which can shift a relativistic electron from the defocusing to the focusing region of the accelerating wakefield, and a decrease in wake phase velocity, which lowers the trapping threshold. The specific method of two-pulse colliding pulse injector was examined using a three-dimensional test particle tracking code. A density down-ramp with a change of density on the order of tens of percent over distances greater than the plasma wavelength led to an enhancement of charge by two orders in magnitude or more, up to the limits imposed by beam loading. The accelerated bunches are ultrashort (fraction of the plasma wavelength, e.g., {approx}5 fs), high charge (>20 pC at modest injection laser intensity 10{sup 17} W/cm{sup 2}), with a relative energy spread of a few percent at a mean energy of {approx}25 MeV, and a normalized root-mean square emittance on the order 0.5 mm mrad.},
doi = {},
journal = {Physical Review E},
number = 2pt2,
volume = 73,
place = {United States},
year = {2005},
month = {7}
}