Three-dimensional structures of MHD flow in a disk generator

Three-dimensional nonuniform plasmas and boundary layers have been studied numerically under an MHD interaction. The nonuniform plasma of "streamer" o wing to weak ionization of seed material has a spiral structure in r-theta plane, and the plasma becomes almost uniform between the wails in r-z plane . This structure is almost the same as that in our previous paper, where th e gas (heavy particle) properties are assumed to be invariant and steady. I n addition to the streamer, the nonuniform plasma of "domain" offing to wea k ionization of noble gas is revealed. The domain has the structure perpend icular to the streamer. In a strong MHD interaction case, the static pressu re considerably increases in the upstream region of a generation channel, a nd the pseudo-shock waves appear in the generator, but the plasma is almost uniform along theta direction. The boundary layer in the strong MHD intera ction is considerably thick, and in the broad region near the wall the Hall current flows reversely. In the weak MHD interaction case, the plasma form s a nonuniform structure along the theta direction, and the Hall current do es not always how in the opposite direction even on the insulator wall sinc e the azimuthal electric field is not zero.