PRELIMINARY-RESULTS FROM THE SPRITES94 AIRCRAFT CAMPAIGN .2. BLUE JETS

Initial observations of a newly documented type of optical emission ab ove thunderstorms are reported. ''Blue jets,'' or narrowly collimated beams of blue light that appear to propagate upwards from the tops of thunderstorms, were recorded on B/W and color video cameras for the fi rst time during the Sprites94 aircraft campaign, June-July, 1994. The jets appear to propagate upward at speeds of about 100 km/s and reach terminal altitudes of 40-50 km. Fifty six examples were recorded durin g a 22 minute interval during a storm over Arkansas, We examine some p ossible mechanisms, but have no satisfactory theory of this phenomenon .