X-ray Flare Spectra from the DIOGENESS Spectrometer and Its Concept Applied to ChemiX on the Interhelioprobe Spacecraft

The DIOGENESS X-ray crystal spectrometer on the CORONAS-F spacecraft operated only for a single month (25 August to 17 September) in 2001, but in its short lifetime obtained one hundred and forty high-resolution spectra of eight solar flares with GOES importance ranging from C9 to X5. The instrument included four scanning flat crystals with wavelength ranges covering the regions of Si xiii (6.65 Å), S xv (5.04 Å), and Ca xix (3.18 Å) X-ray lines and associated dielectronic satellites. Two crystals covering the Ca xix lines were oriented in a “dopplerometer” manner, i.e. such that spatial and spectral displacements, both of which commonly occur in flares, can be separated. We describe the DIOGENESS spectrometer and the spectra obtained during flares that include lines not hitherto seen from spacecraft instruments. An instrument with a very similar concept is currently being built for the two Russian Interhelioprobe spacecraft that are scheduled for launch in 2020 and 2022 and will make a near-encounter (perihelion ∼ 0.3 AU) with the Sun in its orbit. We outline the results that are likely to be obtained.