Fig. 2.

Experimental and synthetic images of the coherent transition radiation. Coherent transition radiation (CTR) is produced at the transport targets’ rear surface when relativistic electrons cross the boundary between the target and vacuum. a–e Experimental data and f–i synthetic CTR calculated from 3D PIC-hybrid simulations of fast electron transport, for the two configurations (i) target out of the coil plane and (ii) target at the coil plane (Fig. 1), with and without imposed B-field. The black horizontal bars, corresponding to 20 μm, give the spatial scale at the emitting target surface. The contour lines correspond to the half-height of the signals. The crossed dashed lines indicate the position of REB injection at the targets’ front laser-irradiated surface. The synthetic images are calculated at the end of the simulation runs and account for all particles having reached the targets’ rear surface