The NASA Global‐scale Observations of the Limb and Disk (GOLD) mission has flown an ultraviolet‐imaging spectrograph on SES‐14, a communications satellite in geostationary orbit at 47.5°W longitude. That instrument observes the Earth's far ultraviolet (FUV) airglow at ~134–162 nm using two identical channels. The observations performed include limb scans, stellar occultations, and images of the sunlit and nightside disk from 6:10 to 00:40 universal time each day. Initial analyses reveal interesting and unexpected results as well as the potential for further studies of the Earth's thermosphere‐ionosphere system and its responses to solar‐geomagnetic forcing and atmospheric dynamics. Thermospheric composition ratios for major constituents, O and N2, temperatures near 160 km, and exospheric temperatures are retrieved from the daytime observations. Molecular oxygen (O2) densities are measured using stellar occultations. At night, emission from radiative recombination in the ionospheric F region is used to quantify ionospheric density variations in the equatorial ionization anomaly (EIA). Regions of depleted F region electron density are frequently evident, even during the current solar minimum. These depletions are caused by the “plasma fountain effect” and are associated with the instabilities, scintillations, or “spread F” seen in other types of observations, and GOLD makes unique observations for their study.

We have measured in the laboratory the far ultraviolet (FUV: 125.0-170.0 nm) cascade-induced spectrum of the Lyman-Birge-Hopfield (LBH) band system (a 1 Π g →X 1 Σ þ g ) of N 2 excited by 30-200 eV electrons. The cascading transition begins with two processes: radiative and collision-induced electronic transitions (CIETs) involving two states (a′ 1 Σ − u and w 1 Δ u → a 1 Π g ), which are followed by a cascade induced transition a 1 Π g →X 1 Σ þ g at the single-scattering pressures employed here. Direct excitation to the a-state produces a confined LBH spectral glow pattern around an electron beam. We have spatially resolved the electron-induced glow pattern from an electron beam colliding with N 2 at radial distances of 0-400 mm at three gas pressures. This imaging measurement is the first to isolate spectral measurements in the laboratory of single-scattering electron-impact-induced fluorescence from two LBH emission processes: direct excitation, which is strongest in emission near the electron beam axis; and cascading-induced, which is dominant far from the electron beam axis. The vibrational populations for vibrational levels from v′ = 0-2 of the a 1 Π g state are enhanced by radiative cascade and CIETs, and the emission cross sections of the LBH band system for direct and cascading-induced excitation are provided at 40, 50, 100, and 200 eV.

Temperature variability of the daytime thermosphere of the Earth is controlled mainly by solar radiation. It is also influenced by wave forcing from the lower atmosphere and geomagnetic forcing from above. During geomagnetic storms energetic particle precipitation at high-latitudes induces, among other effects, ionospheric current systems, Joule heating, and large-scale circulation changes (