Mhd flow in a homopolar device with annular wire  electrodes

Themagnetohydrodynamic flow in a homopolar device with annular linearelectrodes is studied analytically．As the problem is linear, thesolution may be reduced to the summation of elementary solutionsobtained by matching the local solutions in two regions or thehomopolar device. The flow features of the elementary solutionsare discussed. The structure of incomplete electrodes can improvethe Hartmann boundary layer and increase the mass flux of thehomopolar. The elementary solutions are also applied to thediscussion of a homopolar device with continuous electrodes．