Single resonance driven by stochastic pulses

2013-08-13T00:00:00Z (GMT) by G M Nikolopoulos P Lambropoulos

Figure 9. Single resonance driven by stochastic pulses. The average total yield of RA electrons 〈Q2〉 is plotted as a function of the detuning of the driving field from resonance. The symbols are experimental data that have been obtained from the work of [10], and the solid line shows the average signal obtained from our simulations with the Gaussian-correlated field. The dashed line is a fit to the experimental data based on the Voigt profile. Other parameters: Gaussian pulse profile, γ = 0.72Γ2, Γ2τ = 20, \Omega _s^{(0)}=10^{-2}\Gamma _2, 2000 random pulses.

Abstract

Motivated by recent experiments pertaining to the interaction of weak SASE-free-electron-laser (FEL) pulses with atoms and molecules, we investigate the conditions under which such interactions can be described in the framework of a simple phase-diffusion model with decorrelated atom–field dynamics. The nature of the fluctuations that are inevitably present in SASE-FEL pulses is shown to play a pivotal role in the success of the decorrelation. Our analysis is performed in connection with specific recent experimental results from FLASH in the soft x-ray regime.