Summary form only given. A large plume angle and appreciablefraction of wall losses, typical for Hall thrusters, can be attributed,in part, to a relatively high electron temperature, which is required tosustain effective propellant ionization. Due to lower secondary electronemission, the use of metal channel walls should produce a largerelectron temperature than ceramic walls at typical operating conditionsof Hall thrusters. However, segmented electrodes placed along a ceramicchannel of the thruster are experimentally shown to narrow its plume,Even when segmented electrodes are non-emissive or low emissive, theycan still reduce the plume angle, in particular at small mass flowrates. This effect and its dependence on electrode emission capabilitiesand location are investigated by measuring angular ion fluxdistribution, plasma potential distribution, thruster performance andemissive spectral characteristics. To facilitate these investigations, alaboratory Hall thruster with segmented electrodes was operated at avacuum test facility at the PPPL. The thruster utilizes segmentedelectrodes with the possibility of external heating to control totalemission current
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