Nightglow evidence of precipitating energetic electrons in the midlatitude nighttime D region

The intensity range of precipitating electrons with E > 40 kev determined from a previous review of satellite and rocket data by the authors is used to compute the latitude variation of the 3914‐Å and 4278‐Å intensities of the first negative system of N 2 + . The range of computed airglow intensities encompasses the values observed at Saskatoon, Silver Spring, and Kitt Peak located at geomagnetic latitudes of 60°, 50°, and 40°, respectively. Therefore, these >40 kev electrons, which are a potentially significant source of ionization in the nighttime D region, also provide a sufficient energy input to the ionosphere to account for these nightglow observations.