Progress in line-shape modeling of K-shell transitions in warm dense titanium plasmas

Abstract

Modeling of x-ray spectra emitted from a solid-density strongly coupled plasma formed in short-duration, high-power laser-matter interactions represents a highly challenging task due to extreme conditions found in these experiments. In this paper we present recent progress in the modeling and analysis of Kα emission from solid-density laser-produced titanium plasmas. The selfconsistent modeling is based on collisional-radiative calculations that comprise many different processes and effects, such as satellite formation and blending, plasma polarization, Stark broadening, solid-density quantum effects and self-absorption. A rather strong dependence of the Kα shape on the bulk electron temperature is observed. Preliminary analysis of recently obtained experimental data shows a great utility of the calculations, allowing for inferring a temperature distribution of the bulk electrons from a single-shot measurement.

Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser

“…29,30 Additionally, the high spectral resolution allows determination of the plasma temperature by fitting the altered Kα line shape with temperature-dependent line shape models. 31 …”

Absorption-aided x-ray emission tomography of planar targets

“…This is justified when the target is largely homogeneous, which is the case in experiments with ps and sub-ps laser pulses, resulting in an x-ray emission on a ps-time scale; 22 such times are too short for the target to expand or compress noticeably. The calculations can be substantially simplified if, in addition, the resonance absorption is minor (for example, in a previous study, 27 the resonance absorption was inferred to yield a peak value on the order of 0.1 for the K a optical depth s ¼ j r d, to be compared to the non-resonance one j n d % 1:25). Neglecting j r , Eqs.…”

Atomic and optical properties of warm dense copper

“…For high-density plasmas, the effect of plasma environment on the electron population of atomic levels of ions and the number density of free electrons should be considered [11]. The outer electrons can be severely perturbed by the presence of the dense plasma environment.…”

“…The WDM regime is characterized by comparable thermal and Fermi energies and strong ion-ion coupling. The radiative properties of WDM are not well unknown [11]. Describing and characterizing the optical properties of the WDM state associated with temperatures of 1-100 eV and 0.01-10 times of solid density are extremely difficult both theoretically and experimentally.…”