Sprecher
Beschreibung
Plasma wakefield acceleration (PWFA) is a novel acceleration technique with promising prospects for both particle colliders and light sources. However, PWFA research has so far been limited to a few large-scale accelerator facilities worldwide. We present first results on plasma wakefield excitation and acceleration using electron beams generated with the Ti:sapphire lasers ATLAS (LMU, Munich) and DRACO (HZDR, Dresden).
Because of their ultrashort duration and high charge density, the laser-accelerated electron bunches are suitable to drive plasma waves at electron densities in the order of $10^{18}$ to $10^{19}$ cm$^{-3}$. We have capture the beam-induced plasma dynamics with femtosecond resolution using few-cycle optical probing, clearly showing the generation of a plasma wave by the electron beam. In addition to the plasma wave itself, we observe a distinctive transverse ion motion in its trail. This previously unobserved phenomenon can be explained by the ponderomotive force of the plasma wave acting on the ions, resulting in a modulation of the plasma density over many picoseconds [1].
We also present first results on the witness bunch acceleration. The witness is either injected into a subsequent wakefield period during shock-front injection or into the bubble during the density downramp at the exit of the laser wakefield stage. In both cases electron acceleration of the order of tens of MeV is observed.
[1] Gilljohann et al. Direct Observation of Plasma Waves and Dynamics Induced by Laser-Accelerated Electron Beams, Phys. Rev. X 9, 011046 (2019)
| Working group | Invited plenary talk |
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