EUNIS 2013: Unambiguous Evidence for Impulsive Coronal Heating, Data Available

The broad spectral coverage (303-370 Å, 527-635 Å) and unprecedented dynamic range of the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) 2013 sounding rocket observations includes emission lines of ionization stages from He I to Fe XX, and thus a wide temperature range of 0.03 to 10 MK. Pervasive, faint Fe XIX 592 Å line emission was observed in active regions. Comparison of observed line intensities with calculations demonstrates that the Fe XIX emission, formed at temperatures around 8 MK, is evidence of the faint hot emission predicted by impulsive heating models of the solar corona (e.g., ‘nano-flares’). The calibration and availability of the EUNIS-2013 dataset is discussed as well.