Conceptual design problems in future reversed field pinch experiments

The Reversed Field Pinch (RFP) system is of interest as a possible fusion reactor because of its ability to contain a high-beta plasma with relatively long field rise times which minimize the confining magnetic energy and pulsed power supply ratings required. The objectives of the next generation of RFP experiments are to (1) establish a high-beta RFP configuration by means of self reversal which is assisted by field control and sustain it for some tens of msec using additional field control; (2) study the physical properties of the plasma-field configuration during both the setting-up and sustainment phases, as a function of plasma current, and determine the scaling of temperature and confinement time; and (3) study the effect of increasing the current rise times from 2 to 50 msec. The design studies that are discussed are based on a proposal for a future experiment having torus major/minor radii of 1.8/0.6 m with a peak plasma current of about 1.0 MA rising in 1.5 to 15 ms.