Single resonance driven by stochastic pulses

2013-08-13T00:00:00Z (GMT) by G M Nikolopoulos P Lambropoulos
<p><strong>Figure 9.</strong> Single resonance driven by stochastic pulses. The average total yield of RA electrons 〈<em>Q</em><sub>2</sub>〉 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 [<a href="http://iopscience.iop.org/0953-4075/46/16/164010/article#jpb462676bib10" target="_blank">10</a>], 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 = 0.72Γ<sub>2</sub>, Γ<sub>2</sub>τ = 20, \Omega _s^{(0)}=10^{-2}\Gamma _2, 2000 random pulses.</p> <p><strong>Abstract</strong></p> <p>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.</p>