Abstract
An overview of the research capabilities and the future plans on the MA-class
National Spherical Torus Experiment (NSTX) at Princeton is presented. NSTX research is
exploring the scientific benefits of modifying the field line structure from that in more
conventional aspect ratio devices, such as the tokamak. The relevant scientific issues pursued on
NSTX include energy confinement, MHD stability at high β, non-inductive sustainment,
solenoid-free start-up, and power and particle handling. In support of the NSTX research goal,
research tools are being developed by the NSTX team. In the context of the fusion energy
development path being formulated in the US, an ST-based Component Test Facility (CTF) and,
ultimately a high β Demo device based on the ST, are being considered. For these, it is essential
to develop high performance (high β and high confinement), steady-state (non-inductively driven)
ST operational scenarios and an efficient solenoid-free start-up concept. We will also briefly
describe the Next-Step-ST (NSST) device being designed to address these issues in fusionrelevant
plasma conditions.