Mechanism of Toroidal Field Generation by Translation of a Field-Reversed Configuration

The mechanisms of toroidal field generation in translated field-reversed configuration (FRC) plasmas are investigated analytically and numerically. Although the radial electric field in the moving frame together with a translated plasma can be transformed into the toroidal field in the stationary frame, it is negligible and 10⁷ order smaller than the confinement poloidal field. It is found that the axial electric field due to the friction force is insufficient to produce the experimentally observed toroidal field. The Lorentz force acting on electrons translating in the mirror field is found to be accountable for toroidal field generation.