Analysis of Bohm Diffusions Based on the Ion-Neutral Collisions

Three experimental cases of cross-field diffusions in the magnetized plasmas reported to be related with Bohm diffusion are investigated based on the ion current induced by the ion-neutral collisions. High diffusion coefficient for the original Bohm/Simon experiments and the recent experiments of strongly pulsed plasmas can be explained by the gyro-center shift current combined with the short circuit effect, which is different from the turbulence-induced transport of nuclear fusion devices. It can be deduced that Bohm´s interpretation of diffusion with 1/B dependence came from the fact that the short circuit effect of his experiment was limited by the parallel ion velocity. The ratio of azimuthal current density to the discharge current density measured in the pulsed magnetron experiments is analyzed to be constant and independent from the magnitude of magnetic field due to the maximum condition for the Pedersen conductivity.