We report on comprehensive laboratory studies of the K-shell dielectronic recombination resonances of Fe XXV─XXI ions that prominently contribute to the hard X-ray spectrum of hot astrophysical plasmas. By scanning a monoenergetic electron beam to resonantly excite trapped Fe ions in an electron beam ion trap and achieving a high electron─ion collision energy resolution of ∼7 eV, we resolve their respective KLn satellites up to n’=11 . By normalization to known radiative recombination cross sections, we also determine their excitation cross sections and that of the continuum with uncertainties below 15% and verify our results with an independent normalization based on previous measurements. Our experimental data excellently confirm the accuracy and suitability of distorted-wave calculations obtained with the Flexible Atomic Code for modeling astrophysical and fusion plasmas.
