Successful operation of a multijoule output TE CO2laser using a new magnetic‐spiker sustainer excitation circuit is reported. The use of the new excitation circuit has resulted in a significant reduction (∼90%) in the amount of sustainer pulse energy that has to pass through the magnetic switch. In addition, the new circuit technique allows operation of the discharge at reduced voltage (∼50%) and extends the range of excitation current pulse durations (up to ∼7 &mgr;s) over which arc‐free discharges can be formed. The laser has produced a typical output of 5 J at an overall efficiency of ∼13% from a helium‐free gas mixture at a pressure of 400 mbar.