  As part of our laboratory investigation of the theoretical line profiles used
in white dwarf atmosphere models, we extend the electron-density ($n_{\rm e}$)
range measured by our experiments to higher densities (up to
$n_{e}\sim80\times10^{16}$ cm$^{-3}$). Whereas inferred parameters using the
hydrogen-$\beta$ spectral line agree among different line-shape models for
$n_{\rm e}\lesssim30\times10^{16}$ cm$^{-3}$, we now see divergence between
models. These are densities beyond the range previously benchmarked in the
laboratory, meaning theoretical profiles in this regime have not been fully
validated. Experimentally exploring these higher densities enables us to test
and constrain different line-profile models, as the differences in their
relative H-Balmer line shapes are more pronounced at such conditions. These
experiments also aid in our study of occupation probabilities because we can
measure these from relative line strengths.
