Smooth transition from spectral lines to continuum in dense hydrogen plasma

The problem of describing the transition region between a line and continuous spectra of emission in hydrogen or a hydrogen-like plasma is considered, which is most interesting for the case of a dense plasma when the transition region becomes sufficiently wide. The spectral lines and the continuum are typically calculated in different approximations; therefore, the problem of their coordination and matching arises. At present, the method of effective populations is the standard approach. In this work, another approach is used that excludes the problem of joining of the discrete and continuous spectra, since the calculations of both of them are performed within a single approximation. Their comparison with experimental data for $N_e = 10^{15}$–$10^{19}$ cm$^{–3}$ shows good agreement, which is substantially better at high densities than the one provided by the method of effective populations; moreover, this approach can be considered as a substantiation of the latter.