All-reflection interferometer for extreme-ultraviolet airglow studies

Abstract

We describe a possible sounding rocket payload consisting of an interferometer that would observe O I 1304-Å solar and airglow emissions simultaneously and a low-resolution (15-Å) extreme ultraviolet (EUV) spectrometer with a band pass between 250 and 1050 Å to measure the solar EUV flux, a primary source for the O I 1304-Å dayglow emission. The solar measurements, the first of their kind, could provide detailed information on the column of O along the line of sight of the instrument as well as information on the full disk solar line profile, which is important to planetary as well as cometary physics. The information gained through line profile studies of the dayglow includes the relative contribution of the two main excitation mechanisms, photoelectron impact and solar resonance scattering, and a means to verify cross sections and branching ratios. Furthermore, valuable information on optically thick cascade enhancement can be ascertained. All such information will substantiate sophisticated models, electron and radiative transport, that can be utilized in the remote sensing of the thermosphere.