The leading role of the n=1 toroidal mode in high β rotating magnetic field driven FRC*

Odd-parity rotating magnetic field (RMFo), which maintains closed field topology in FRC (field reversed configutarion), exhibits great potential in efficient toroidal current drive and plasma heating for high-β compact toroid. Based on the Princeton Field-Reversed Configuration (PFRC-2) experiment [1], by employing the warm plasma assumption and rigid rotor (RR) model, numerical calculation show that a FRC can be formed in a few microseconds with the amplitude ratio of RMFo to vacuum axial magnetic field less than 0.05; more important, theoretical analysis implies that the n =1 toroidal mode may be the main contributor for initial inward RMFo penetration as the radial electron diffusion is considered. These results provide some clues for solving the instability problem at the micro level in the future.