Fig. 4: The effect of normalized emittance ϵN on the saturated X-ray power of an LDFEL driven by a flying-focus or conventional laser pulse.
From: X-ray free-electron lasing in a flying-focus undulator
The X-ray power drops from ≈1 MW to a plateau at ≈40 kW as the normalized emittance is increased from ϵN = 0 to ϵN = 0.37 μm-rad. The initial emittance does not change the fact that a flying-focus pulse (green circles) requires less energy than a conventional pulse (red triangles). The inset displays the evolution of the X-ray power (green) and bunching factor (blue) for a flying-focus undulator with ϵN = 0.28 μm-rad. All results were obtained from 3D, time-dependent simulations with the LDFEL-modified version of GENESIS-1.3.
