Resonant Auger effect at high x-ray intensity

The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s -> 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient (similar to 10(18) W/cm(2)) to induce Rabi oscillations between the neon ground state and the is 1s(-1)3p (P-1) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission., Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.