Comment on "Effects of magnetic field gradient on ion beam current in cylindrical Hall ion source". [J. Appl. Phys. 102, 123305 (2007)]

It is argued that the key difference in the cylindrical Hall thruster (CHT) as compared to the end-Hall ion source cannot be exclusively attributed to the magnetic field topology [Tang et al., J. Appl. Phys. 102, 123305 (2007)]. With a similar mirror-type topology, the CHT configuration provides the electric field with nearly equipotential magnetic field surfaces and a better suppression of the electron cross-field transport, as compared to both the end-Hall ion source and the cylindrical Hall ion source of [Tang et al., J. Appl. Phys. 102, 123305 (2007)]. 0 2008 American Institute of Physics. [DOI: 10.1063/1.2976361]