Progress towards steady state on NSTX

Abstract

In order to reduce recirculating power fraction to acceptable levels, the spherical torus concept relies on the simultaneous achievement of high toroidal and high bootstrap fraction in steady state. In the last year, as a result of plasma control system improvements, the achievable plasma elongation on NSTX has been raised from 2.1 to 2.6-approximately a 25% increase. This increase in elongation has led to a substantial increase 0029-5515/06/030022+07$30.00