Speaker
Description
The longitudinal structure of ultra-short electron bunches generated by Laser wakefield accelerators (LWFAs) is strongly shaped by the rapid injection dynamics and the interaction between the laser and the electron beam throughout the acceleration process. A detailed understanding of these bunch structures is essential for advancing compact FELs and further secondary light sources.
We present experimental results based on spectral single-shot measurements of broadband coherent transition radiation (UV to mid-IR, 250nm-11.35μm) from LWFA electron bunches passing through a metal foil. By analyzing the transition radiation spectra, we reconstruct electron bunch profiles including sensitivity and uniqueness properties. We show that electron bunches originating from different injection regimes exhibit complex longitudinal structures spanning multiple time scales — from the overall bunch envelope to sub-micrometer microstructures. These features vary with the injection regime and correlate with signatures in the electron spectrometer. Microstructures on the scale of the laser wavelength and its harmonics arise from laser–electron interactions during acceleration.
