Method for the precise measurement of wavelengths for main shell transitions in $\rm He$- and $\rm Li$-like $\rm Ca$ ions

A possible approach to obtain a precise experimental data on the atomic structure of highly charged ions is considered. Since the key point determining measurement accuracy is the presence of reference lines with precisely known wavelengths, it is proposed first to to use hydrogen-like reference lines for precise measurements of the helium-like resonant transition and their dielectronic satellites. Then in turn these lines, which exist in the plasma over a wide temperature range, can be used as the reference in the wavelength measurement for other ions. The problems associated with the creation of the plasma conditions under which the reference and measured lines have comparable intensities are discussed. The irradiation of minerals with laser pulses, which, in terms of their chemical composition, are a set of elements with average $15 < Z < 30$ and light $Z < 15$ nuclear charges, is proposed. Several experimental schemes to measure the wavelengths of the spectral lines of multiply charged calcium ions with an expected error of up to $0.125$ mÅ are considered as an example.