Investigation of TE discharges in a 1.6‐mm square channel has revealed reasons for the inefficient operation of such devices as CO2oscillators. At high repetition rates the pulsed glow discharges are not wall confined above 100 Torr. Thus wall cooling and complete volumetric excitation are reduced. Energy deposited into the cathode fall region creates considerable problems. At low pressures this energy is a large fraction of the total discharge energy, whereas for higher pressures the power and power density deposited in this region is very high. The resultant localized gas heating dissociates molecules, creates turbulence, and limits gain.