Toroidal asymmetries in divertor impurity influxes in NSTX

"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...

Simulation of Power and Particle Flows in the NSTX Edge Plasma

We simulate edge plasmas in NSTX double-null divertor configurations with the UEDGE two-dimensional fluid code. The carbon impurity density in the core plasma and total radiated power increase with the core heating power and the magnitude of the physical and chemical sputtering in the divertor. Up/down plasma asymmetries are generated by classical cross-field particle drifts. With the standard ...

Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U.

A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal ang...

Calculation of impurity poloidal rotation from measured poloidal asymmetries in the toroidal rotation of a tokamak plasma.

To improve poloidal rotation measurement capabilities on the DIII-D tokamak, new chords for the charge exchange recombination spectroscopy (CER) diagnostic have been installed. CER is a common method for measuring impurity rotation in tokamak plasmas. These new chords make measurements on the high-field side of the plasma. They are designed so that they can measure toroidal rotation without the...