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The metastable lower level of the He I 10830 line in active cool stars is believed to be populated by recombination following photoionization of neutral Helium present in the upper chromosphere. This transition is a powerful diagnostic of atmospheric dynamics of cool stars [1,4]. The EUV flux radiated in the corona (the ionization edge of He I is at 24.58 eV, or 504.27 Å) is responsible for...