Dynamic Stark broadening as the Dicke narrowing effect

A very fast method to account for charged particle dynamics effects in calculations of spectral line shape emitted by plasmas is presented. This method is based on a formulation of the frequency fluctuation model (FFM), which provides an expression of the dynamic line shape as a functional of the static distribution of frequencies. Thus, the main numerical work rests on the calculation of the quasistatic Stark profile. This method for taking into account ion dynamics allows a very fast and accurate calculation of Stark broadening of atomic hydrogen high-$n$ series emission lines. It is not limited to hydrogen spectra. Results on helium-$\beta$ and Lyman-$\alpha$ lines emitted by argon in microballoon implosion experiment conditions compared with experimental data and simulation results are also presented. The present approach reduces the computer time by more than 2 orders of magnitude as compared with the original FFM with an improvement of the calculation precision, and it opens broad possibilities for its application in spectral line-shape codes.

Figure 1

Lyman-$\alpha$ line with fine structure at $N_e=1.5\times {10}^{23}{\text{cm}}^{-3}$ and $T_e={10}^7\text{K}$. Comparisons between static profile (dash line), dynamic profile (full line) and molecular dynamics simulation calculation (circles).

Figure 2

Lyman-$\alpha$ line with fine structure at $N_e=1.5\times {10}^{23}{\text{cm}}^{-3}$ and $T_e={10}^7\text{K}$. Dynamic profile with different fluctuation rates, $\Gamma$ (full line: same as Fig. 1 with $\Gamma =1.5$, stars: $\Gamma =10$, and triangles: $\Gamma =100$) compared to unperturbed profile obtained with a zero ionic electric field (dash line).

Figure 3

Balmer 10–2 and Paschen 10–3 lines at $N_e={10}^{14}{\text{cm}}^{-3}$ and $T_e=10\text{eV}$. Comparisons between static profile (dash line) and dynamic profile (full line).

Figure 4

Ar XVII $1s^2\text{−}1s3p$ ${}^{1}P$ at $N_e=1.2\times {10}^{24}{\text{cm}}^{-3}$ and $T_e=700\text{eV}$. Comparison of the full ion dynamics calculation including the Li-like satellites (bold full line) with the experimental data (circles) and the static profile (thin full line).