Parametrization of the Zeeman effect for hydrogen-like spectra in high-temperature plasmas

We present a method for parametrizing the Zeeman effect in hydrogen-like systems in high-temperature plasmas, where the fine-structure is completely unresolved. The method is based on the observation that the different polarization components behave collectively like separate entities, with simple relations. The entire Zeeman pattern can then be reduced to just three components, whose dependence on the magnetic field and the temperature can be described by only three numerical parameters. This makes it possible to include the influence of the Zeeman effect directly into ion temperature diagnostic procedures with minimal increase in the required computational effort and without the need for pre-calculated correction factors. We have tabulated such parametrizations—which are accurate for a wide range of fields and temperatures, even for cases when the total line-shape is no longer Gaussian—for 44 commonly studied hydrogen-like transitions. The effects of non-statistical population distribution in the upper sub-levels are briefly discussed, and we also note a temperature-dependent wavelength shift of the centre positions of the transitions.