DocumentCode :
228170
Title :
Accordion effect in plasma channels: Generation of tunable comb-like electron beams
Author :
Kalmykov, S.Y. ; Shadwick, B.A. ; Ghebregziabher, I. ; Davoine, X. ; Lehe, R. ; Lifschitz, A.F. ; Malka, V.
Author_Institution :
Dept. of Phys. & Astron., Univ. of Nebraska-Lincoln, Lincoln, NE, USA
fYear :
2014
fDate :
25-29 May 2014
Firstpage :
1
Lastpage :
6
Abstract :
Propagating a short, relativistically intense laser pulse in a plasma channel makes it possible to generate comb-like electron beams for advanced radiation sources. The ponderomotive force of the leading edge of the pulse expels all electrons facing the pulse. The bare ions attract the ambient plasma electrons, forming a closed bubble of electron density confining the pulse tail. The cavity of electron density evolves slowly, in lock-step with the optical driver, and readily traps background electrons. The combination of a bubble (a self-consistently maintained, “soft” hollow channel) and a preformed channel forces transverse flapping of the laser pulse tail, causing oscillations in the bubble size. The resulting periodic injection produces a sequence of background-free, quasi-monoenergetic bunches of femtosecond duration. The number of these spectral components, their charge, energy, and energy separation is sensitive to the channel radius and pulse length. Accumulation of noise (continuously injected charge) can be prevented using a negatively chirped drive pulse with a bandwidth close to a one-half of the carrier wavelength. As a result of dispersion compensation, self-steepening of the pulse is reduced, and continuous injection almost completely suppressed. This level of control on a femtosecond time scale is hard to achieve with conventional accelerator techniques. These comb-like beams can drive high-brightness, tunable, multi-color γ-ray sources.
Keywords :
bubbles; electron beams; electron density; plasma density; plasma light propagation; plasma oscillations; accelerator techniques; accordion effect; background electron traps; bubble size; dispersion compensation; electron density; energy separation; femtosecond time scale; high-brightness gamma-ray sources; multicolor gamma-ray sources; negatively chirped drive pulse; noise accumulation; optical driver; plasma channels; plasma oscillations; ponderomotive force; radiation sources; relativistically intense laser pulse propagation; spectral components; tunable comb-like electron beam generation; tunable gamma-ray sources; Acceleration; Bandwidth; Chirp; Electron beams; Laser beams; Oscillators; Plasmas;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Plasma Sciences (ICOPS) held with 2014 IEEE International Conference on High-Power Particle Beams (BEAMS), 2014 IEEE 41st International Conference on
Conference_Location :
Washington, DC
Print_ISBN :
978-1-4799-2711-1
Type :
conf
DOI :
10.1109/PLASMA.2014.7012740
Filename :
7012740
Link To Document :
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