Convergence of the algorithm discussed in section 2

2013-08-13T00:00:00Z (GMT) by G M Nikolopoulos P Lambropoulos
<p><strong>Figure 3.</strong> Convergence of the algorithm discussed in section <a href="" target="_blank">2</a>. The modulus of <em>g</em><sup>(1)</sup>(<em>t</em>, <em>t</em>') is plotted as a function of <em>t</em> − <em>t</em>'. Averaging over a large number of pulses (trajectories), |<em>g</em><sup>(1)</sup>(<em>t</em>, <em>t</em>')| converges to equation (<a href="" target="_blank">12</a>) (grey thick line). Other parameters: τ = 10 fs, σ<sub>ω</sub> = 0.25 rad fs<sup>−1</sup>.</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>