Observations of transitions of hydrogen-like Fe XXVI in solar flare spectra

Observations of solar flare spectra over the wavelength range 1.769-1.796 A with the Bent Crystal Spectrometer on the NASA Solar Maximum Mission satellite are presented. The 2P3/2, 2P1/2 and associated satellite transitions of Fe XXVI are identified, their intensities and widths estimated and the results compared with theoretical predictions. For two spectra, which include the isolated n = 2 satellite features, the observations can be reproduced by plasma temperatures of 24,000,000 and 28,400,000 K. Linewidth measurements show evidence for nonthermal velocities of up to 150 km/s. Emission measures derived from the Fe XXVI observations are compared with those from lower temperature Ca XIX and Fe XXV measurements and an emission measure decreasing with temperature is found.