Flux generation and sustainment of a field reversed configuration with rotating magnetic field current drive

A new experimental device has been constructed to study the flux build-up a nd sustainment of a field reversed configuration (FRC) with a rotating magn etic field (RMF). Even though complete penetration was expected from RMF th eory, the RMF field was observed to penetrate only a few centimeters inside the FRC separatrix. Despite the limited penetration, significantly larger toroidal currents (40 kA) were driven than in previous experiments (similar to 2 kA) with the same RMF field. The high currents and lack of deep penet ration allowed the axial field to be the dominant field throughout the FRC. The radially inward pondermotive force arising from axial screening curren ts at the FRC edge had a significant influence on energy and particle confi nement, reducing convective losses to the limit of observability. With only ohmic heating, the measured low ion temperatures (2 eV) left the ions unma gnetized while the electrons (similar to 40 eV) were well magnetized. No de structive instability was observed for the RMF driven FRC despite the lack of a strong kinetic ion component. (C) 2000 American Institute of Physics. [S1070-664X(00)96305-5].