A 10 fs X-ray emission switch driven by an intense X-ray free electron laser

We propose an intrinsic fast X-ray switch driven by the radiation emission from hollow ion states (KLn)-L-0. The switch is designed primarily for the investigation of the transient evolution of X-ray emission from high density plasmas created by short pulses (< 1 ps). These plasmas usually terminate with a recombination regime at low density. If usual time integrated spectroscopic streak techniques are employed, the current time resolution is limited (> 0.5 ps) and the X-ray emission from the low density regime can only be suppressed with a fast switch approach. Simulations carried out for short pulse (100 fs) intense X-ray free electron laser radiation (XFEL) interacting with dense plasmas demonstrate that the hollow ion X-ray emission switch has a time scale faster than 50 fs. This time window enables the probing of plasmas of the highest density even if time integrated spectroscopic techniques are employed. (C) 2007 Published by Elsevier B.V.