THE OPTICAL-SPECTRUM OF AIRCRAFT ST ELMOS FIRE

On February 26, 1995, during a NASA sponsored mission to Peru to study red sprites and blue jets, the instrumented Westwind 2 jet aircraft e ncountered spectacular St. Elmo's fire from the wing pods, tail and no se while flying through a cloud at an altitude of 13.83 km (45,376 ft) . The phenomenon was captured on low light level monochromatic and col or television systems aboard the aircraft, and its spectrum was record ed on a low light level TV spectrograph with response from 395.0 to 75 0.0 nm. The cameras and spectrograph also recorded scattered intra-clo ud lightning and a possible lightning discharge near, or to, the aircr aft. The spectrum of St. Elmo's fire was primarily the second (2nd) po sitive bands of N-2. The data were consistent with a population of ele ctrons having relatively low energy (<18 eV).