Abstract
In the Himeji FACT device, the poloidal magnetic flux of spheromak was amplified successfully by injecting the magnetic helicity electrostatically. It was verified by investigating the magnetic field structures that the spheromak configuration with the external flux, being different from the simple spheromak, was generated in the flux conserver. This external flux and the Z current flowing along it play a major part in the flux conversion from toroidal to poloidal flux. We studied the conservation of helicity by doing the helicity balance tests in the FACT system. A threshold for helicity injection from the plasma source was determined to be λg.c-10 m-1.
