RUNAWAY ELECTRONS AS A SOURCE OF RED-SPRITES IN THE MESOSPHERE

Large quasi-electrostatic (QE) fields above thunderclouds [Pasko et al , 1995] produce an upward traveling beam of similar to 1 MeV runaway e lectrons which may contribute to the production of optical emissions a bove thunderclouds referred to as Red Sprites. Results of a one dimens ional computer simulation model suggest that the runaway electrons can produce optical emissions similar in intensity and spectra to those o bserved in Red Sprites, but only for large QE fields produced by posit ive CG discharges lowering 250 C or more to ground from an altitude of at least 10 km. Differences in predicted optical spectra from that of other mechanisms suggest that the runaway electron mechanism can be r eadily tested by high resolution spectral measurements of Red Sprites.