Table 1 Parameters of laser-driven FEL simulations comparing flying-focus and conventional laser undulators
From: X-ray free-electron lasing in a flying-focus undulator
LDFEL parameters | |
Target resonant wavelength (nm) | λX0 = 2.16 |
Laser wavelength (μm) | λL = 10 |
Field amplitude/undulator strength | a0 = 0.35 |
FEL parameter | ρ = 3.09 × 10−4 |
1D cold beam gain length (mm) | Lg0 = 0.74 |
Ideal saturation length (mm) | Lsat = 10.3 |
Electron beam parameters | |
Energy (mc2) | γ0 = 35 |
Current (kA) | Ib = 1 |
Minimum RMS radius (μm) | σ0 = 15 |
Normalized emittance (μm-rad) | ϵN ≪ 0.37 |
Energy spread | Δγ/γ0 ≪ 3.09 × 10−4 |
Conventional focus | |
Transverse profile | Gaussian |
Pulse duration (ps) | T = 83 |
Rayleigh range (cm) | ZR = 0.11, 1.25, 2.50 |
Spot size (μm) | wC = 60, 200, 283 |
Pulse energy (J) | UC = 8, 88, 176 |
Flying focus | |
Transverse profile | Flattened Gaussian beam63 |
Focal range (cm) | Lf = 1.25 |
Pulse duration (ps) | T = 83 |
Gaussian spot size at focus (μm) | wFF = 37.5 |
Gaussian spot at lens (cm) | wl = 8.5 |
Pulse energy (J) | UFF = 8 |
