Hybrid MHD model for a driven, ion-current FRC

Typical MHD models do not include the effects of a finite-electric field, finite gyro-radius, and gyro-period. The magnetohydrodynamic code, MACH2, is modified in one dimension to account for two-fluid behavior, in order to include these effects during the formation of a “driven”, field-reversed configuration (FRC). The simulation is run for a period of 150 μs, during which time an azimuthal ion current accelerates, the FRC forms, compresses radially and axially, and then begins to decay. Once the FRC is formed, an electron current develops, which sharpens the magnetic-field profile outside the null-field region. The equilibrium that is formed is characteristic of a Rigid Rotor.[1] The simulations also agree with prior experiments,[2] specifically the r-z shape of the FRC and the magnitude of the total current, including the ion and electron flows.