In order to reduce recirculating power fraction to acceptable levels, the spherical torus concept relies on the
simultaneous achievement of high toroidal β 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
κ ∼ 2.1 to κ ∼ 2.6—approximately a 25% increase. This increase in elongation has led to a substantial increase in the toroidal β for long pulse discharges. The increase in β is associated with an increase in plasma current at
nearly fixed poloidal β, which enables higher βt with nearly constant bootstrap fraction. As a result, for the first
time in a spherical torus, a discharge with a plasma current of 1MA has been sustained for 1 s (0.8 s current flat-top).
Data are presented from NSTX correlating the increase in performance with increased plasma shaping capability. In
addition to improved shaping, H-modes induced during the current ramp phase of the plasma discharge have been
used to reduce flux consumption and to delay the onset of MHD instabilities. Based on these results, a modelled
integrated scenario, which has 100% non-inductive current drive with very high toroidal β, will also be discussed.
The NSTX poloidal field coils are currently being modified to produce the plasma shape which is required for this
scenario, which requires high triangularity (δ ∼ 0.8) at elevated elongation (κ ∼ 2.5). The other main requirement
of steady state on NSTX is the ability to drive a fraction of the total plasma current with RF waves. The results of
high harmonic fast wave heating and current drive studies as well as electron Bernstein wave emission studies will
be presented.