Advances in boronization on NSTX-Upgrade

"Snowflake" divertor configuration in NSTX

Toroidal Alfvén Eigenmode Avalanches in NSTX

The transport of fast-ions resulting from strongly non-linear Toroidal Alfvén Eigenmode avalanches has been studied experimentally and simulated with the NOVA ideal MHD code and the ORBIT code to model fast ion transport. Detailed measurements of the multi-mode structure and amplitudes have been made to benchmark NOVA calculations of eigenmodes. The ORBIT code has been used to model the fast-io...

The Use of MDSplus on NSTX at PPPL

The MDSplus data acquisition system has been used successfully since the 1999 startup of the National Spherical Torus Experiment (NSTX) for control, data acquisition and analysis for diagnostic subsystems. Prior to first plasma on NSTX, software engineers collectively spent 1 man-year to learn the system and bring it to operation, and 4 full-time equivalents continue to support its uses. The 30...

Electron Bernstein Wave Research on CDX-U and NSTX

Mode-converted electron Bernstein waves (EBWs) potentially allow the measurement of local electron temperature (Te) and the implementation of local heating and current drive in spherical torus (ST) devices, which are not directly accessible to low harmonic electron cyclotron waves. This paper reports on the measurement of X-mode radiation mode-converted from EBWs observed normal to the magnetic...

Simulation of microtearing turbulence in NSTX

Thermal energy confinement times in NSTX dimensionless parameter scans increase with decreasing collisionality. While ion thermal transport is neoclassical, the source of anomalous electron thermal transport in these discharges remains unclear, leading to considerable uncertainty when extrapolating to future ST devices at much lower collisionality. Linear gyrokinetic simulations find microteari...