Application of anomalous magnetic field swelling phenomenon to formation of field-reversed configuration in linear theta pinch

A field-reversed configuration(FRC) is formed by making use of the so-called anomalous magnetic field swelling arising in a linear theta pinch. The magnetic flux trapped during the first half period of the main discharge is utilized as the reverse bias flux necessary to form the closed configuration. This bias field can be adjusted to become maximum during the second half period of the main discharge current by changing the filling pressure and the delay time between the preionization and the main discharge. A driven coil is added to the device in order to control the reconnection of the magnetic field lines in each end region of the main coil. A FRC plasma seems to be successfully produced with a fairly large separatrix which is desirable from the point of view of its stability and lifetime. The flux loss during the field reconnection is also suppressed in this formation. (author)