Multi-Color Γ-Rays From Comb-Like Electron Beams Driven By Incoherent Stacks Of Laser Pulses, Serge Y. Kalmykov, X. Davoine, Isaac Ghebregziabher, Bradley A. Shadwick
Mar 2017
Multi-Color Γ-Rays From Comb-Like Electron Beams Driven By Incoherent Stacks Of Laser Pulses, Serge Y. Kalmykov, X. Davoine, Isaac Ghebregziabher, Bradley A. Shadwick
Serge Youri Kalmykov
Trains of fs-length, GeV-scale electron bunches with controlled energy spacing and a 5-D brightness up to
10^17 A/m^2 may be produced in a mm-scale uniform plasma. The main element of the scheme is an incoherent stack of 10-TW-scale laser pulses of different colors, with mismatched focal spots, with the highest-frequency pulse advanced in time. While driving an electron density bubble, this stack remains almost proof against nonlinear red-shift and self-compression. As a consequence, the unwanted continuous injection of background electrons is minimized. Weak focusing of the trailing (lower-frequency) component of the stack enforces expansions and contractions of the bubble, inducing …
High-Flux Femtosecond X-Ray Emission From Controlled Generation Of Annular Electron Beams In A Laser Wakefield Accelerator, T. Z. Zhao, K. Behm, C. F. Dong, X. Davoine, Serge Y. Kalmykov, V. Petrov, Vladimir Chvykov, P. Cummings, B. Hou, Anatoly Maksimchuk, J. A. Nees, Victor Yanovsky, A. G. R. Thomas, Karl Krushelnick
Aug 2016
High-Flux Femtosecond X-Ray Emission From Controlled Generation Of Annular Electron Beams In A Laser Wakefield Accelerator, T. Z. Zhao, K. Behm, C. F. Dong, X. Davoine, Serge Y. Kalmykov, V. Petrov, Vladimir Chvykov, P. Cummings, B. Hou, Anatoly Maksimchuk, J. A. Nees, Victor Yanovsky, A. G. R. Thomas, Karl Krushelnick
Serge Youri Kalmykov
Annular quasimonoenergetic electron beams with a mean energy in the range 200–400 MeV and charge on the order of several picocoulombs were generated in a laser wakefield accelerator and subsequently accelerated using a plasma afterburner in a two-stage gas cell. Generation of these beams is associated with injection occurring on the density down ramp between the stages. This well-localized injection produces a bunch of electrons performing coherent betatron oscillations in the wakefield, resulting in a significant increase in the x-ray yield. Annular electron distributions are detected in 40% of shots under optimal conditions. Simultaneous control of the pulse duration and …
Controlled Generation Of Comb-Like Electron Beams In Plasma Channels For Polychromatic Inverse Thomson Gamma-Ray Sources, Serge Y. Kalmykov, X. Davoine, I Ghebregziabher, R Lehe, A F. Lifschitz, B A. Shadwick
Feb 2016
Controlled Generation Of Comb-Like Electron Beams In Plasma Channels For Polychromatic Inverse Thomson Gamma-Ray Sources, Serge Y. Kalmykov, X. Davoine, I Ghebregziabher, R Lehe, A F. Lifschitz, B A. Shadwick
Serge Youri Kalmykov
Propagating a relativistically intense, negatively chirped laser pulse (the bandwidth > 150 nm) in a plasma channel makes it possible to generate background-free, comb-like electron beams - sequences of synchronized bunches with a low phase-space volume and controlled energy spacing. The tail of the pulse, confined in the accelerator cavity (an electron density ‘bubble’), experiences periodic focusing, while the head, which is the most intense portion of the pulse, steadily self-guides. Oscillations of the cavity size cause periodic injection of electrons from the ambient plasma, creating an electron energy comb with the number of components, their mean energy, and energy …
