As part of our laboratory investigation of the theoretical line profiles used in white dwarf atmosphere models , we extend the electron-density ( n _ { e } ) range measured by our experiments to higher densities ( up to n _ { e } \sim 80 \times 10 ^ { 16 } cm ^ { -3 } ) .
Whereas inferred parameters using the hydrogen- \beta spectral line agree among different line-shape models for n _ { e } \lesssim 30 \times 10 ^ { 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 .