Seminari di gruppo IV

Paolo Tomassini, "High Brightness and ultrashort electron beams with the Laser Wake Field Acceleration method"




The Laser Wake Field Acceleration (LWFA) occurs when an ultraintense and ultrashort laser pulse excites a large-amplitude longitudinal plasma wave, which can accelerate electron beams with gradients of 100’s GV/m. LWFA  is now routinely employed to generate electron beams with hundreds of MeV’s energy and with nC scale charge, but with poor control on the beam quality. To foster the development of large energy (hundreds of GeV’s or more) and/or high quality demanding application as quasi monochromatic Compton/Thomson or Free Electron Laser X/gamma sources, existing high-quality electron injection schemes should be optimized and experimentally tested.  In the seminar, two high-quality injection schemes will be discussed in detail. The downramp injection [1], along with its numerous variants, had been numerically and experimentally demonstrated being capable of generating high-quality beams [2] and high-brightness beams suitable to drive an FEL [3]. The Resonant Multi Pulse Ionization Injection [4] is now reaching a maturity stage in which the scheme can be employed with the usage of a single laser pulse, whose main portion is split in two pulses which drive a large amplitude plasma wave, while the remaining small portion is frequency doubled/tripled so as to extract the electrons from Argon atoms in the target [5]. Electron beams as short as a few hundreds of femtoseconds and with unprecedented brightness can be generated in this way.

[1] S. Bulanov et al., Phys. Rev. E 58, R5257 (1998)

[2]  P. Tomassini et al., PRST 6 12 (2003)

[3]  W. Wang et al., Nature 595 (2021  

[4] P. Tomassini et al.,  Physics of Plasmas,  24 10,  (2017)  

[5] P. Tomassini et al., in preparation