Interaction of ultra-short electromagnetic pulses with ions in hot dense plasmas

Abstract

The general properties of ultra-short electromagnetic pulse (USP) interactions with highly charge ions in dense and high temperature plasmas are considered. The application of USP in X-ray spectral range provided by modern technology including free-electron laser machines opens up new opportunities for investigations of dense plasmas. They are based on the possibility of USP penetration into optically dense media due to their broad spectral distribution. In the framework of the use of USP for active spectroscopy in high energy density plasmas, new expressions of the transition probabilities are proposed. An aluminum plasma at local thermodynamic equilibrium is considered. The interaction of USP with hydrogen-like ions at Ne = 2⋅1022 cm−3 and T = 1 keV is analyzed in details by taking into account both the specificity of the USP and the plasma effects, such as Stark and Doppler effects on the line profile of the excited radiative transitions. The results are applied for demonstration of optical depth and pulse duration effects on excitation probabilities of the n = 1–n = 3 radiative transition, which is the simplest atomic scheme to observe fluorescence signal.