Recent electron beam injection experiments in the lower ionosphere have been produced two perplexing results: 1. At altidues from 140 km to 220 km, the beam associated 391.4 nm intensity is relatively independent of altitude despite the decreasing N2 abundance. 2. The radical extent (1B) of the perturbed region populated by beam associated energetic electrons significantly exceeds the nominal gyrodiameter for 90¿ injection. A series of laboratory measurements is described in which both of these flight results appear to have been closely reproduced. The laboratory results are reasonably consistent with the transition from a collision dominated to collisionless beam-plasma discharge configuration.