Magnetic field topography of the anode layer thruster

Summary form only given. The anode layer thruster (TAL) built by the Central Scientific Research Institute of Machine Buildings (TsNIMASH) of Kaliningrad, Russia is currently being investigated in the US for both primary and auxiliary spacecraft propulsion. The TAC is a Hall accelerator which consists of an inner electromagnet, three outer electromagnets, an annular anode through which xenon propellant is supplied, and a hollow cathode neutralizer. The radial magnetic field created by the electromagnets crosses with the axial magnetic field to produce an azimuthal drift of electrons. The magnetic field has been mapped using water-cooled Hall probes both while the thruster was operating and with only the vacuum field generated by the electromagnets. The measured radial magnetic field strength decreased by approximately two-thirds during operation of the thruster. Preliminary estimates to determine the role of the azimuthal electron current indicated that nearly 800 A were required to effect this change. Additional experiments were conducted to examine the error in the Hall probe measurements and to investigate the nature of the decrease in magnetic field strength.