× B Plasma Rotation and n = 1 Oscillation Observed in the NSTX - CHI Experiments

An overview of recent physics results from NSTX

The National Spherical Torus Experiment (NSTX) is currently being upgraded to operate at twice the toroidal field and plasma current (up to 1 T and 2 MA), with a second, more tangentially aimed neutral beam (NB) for current and rotation control, allowing for pulse lengths up to 5 s. Recent NSTX physics analyses have addressed topics that will allow NSTX-Upgrade to achieve the research goals cri...

Experimental Demonstration of Tokamak Inductive Flux Saving by Transient Coaxial Helicity Injection on NSTX

Discharges initiated by Transient Coaxial Helicity Injection (CHI) in NSTX have attained peak toroidal plasma currents up to 300 kA. When induction from the central solenoid is then applied, these discharges develop up to 300 kA additional current compared to discharges initiated by induction only. CHI initiated discharges in NSTX have achieved 1 MA of plasma current using only 258 mWb of solen...

Solenoid-free Plasma Start-up in NSTX using Transient CHI

Experiments in NSTX have now demonstrated the coupling of toroidal plasmas produced by the technique of Coaxial Helicity Injection (CHI) to inductive sustainment and ramp-up of the toroidal plasma current. In these discharges, the central Ohmic transformer was used to apply an inductive loop voltage to discharges with a toroidal current of about 100 kA created by CHI. The coupled discharges hav...

Solenoid-free Plasma Start-up in HIT-II and NSTX using Transient CHI

Resistive Wall Mode Stabilization and Plasma Rotation Damping Considerations for Maintaining High Beta Plasma Discharges in NSTX

Maintaining steady fusion power output at high plasma beta is an important goal for future burning plasmas such as in ITER advanced scenario operation and a fusion nuclear science facility. Research on the National Spherical Torus Experiment (NSTX) is investigating stability and control physics to maintain steady high plasma normalized beta with minimal fluctuation. Resistive wall mode (RWM) in...