A scalable system for real-time analysis of electron temperature and density based on signals from the Thomson scattering diagnostic, initially developed installed NSTX-U experiment, was recently adapted Large Helical Device operated first time during plasma discharges. During its initial operation run, it routinely recorded processed four spatial points at laser repetition rate 30 Hz, well wit...

We report on the status of a set of ITPA-sponsored experiments among the Alcator C-Mod, MAST and NSTX devices to compare the characteristics and access conditions of small edge-localized modes (ELMs). Small ELM discharges were developed in each of the machines, and common features were identified, both in terms of ELM structure and operational windows. A common observation is an apparent βped t...

Recent experiments on the spherical tokamak have discovered the conditions to create a powerful plasma and ensure easy shaping and amplification of stability, high bootstrap current and confinement energy. The spherical tours (ST) fusion energy development path is complementary to the tokamak burning plasma experiment such as NSTX and higher toroidal beta regimes and improves the design of a po...

Impact of the SOL and divertor conditions on access to H-mode H Meyer1 1CCFE, Culham Science Centre, Abingdon, OX14 3DB, UK E-mail: [email protected] The formation of an edge transport barrier in the so-called H-mode was discovered nearly 30 years ago, but the trigger mechanism still eludes first principle understanding. This leads to large uncertainties in our projections towards future...

The AMR (Antenna—Mode-conversion—Ray-tracing) code [1, 2] has been recently coupled with the LUKE [3] Fokker-Planck code. This modeling suite is capable of complex simulations of electron Bernstein wave (EBW) emission, heating and current drive. We employ these codes to study EBW heating and current drive performance under spherical tokamak (ST) configurations—typical NSTX discharges are employ...

A model for simulating the diffusive evaporation of lithium into a helium filled NSTX vacuum vessel is described and validated against an initial set of deposition experiments. The DEGAS 2 based model consists of a three-dimensional representation of the vacuum vessel, the elastic scattering process, and a kinetic description of the evaporated atoms. Additional assumptions are required to accou...

A novel and compact, diode-based, multi-energy soft x-ray (ME-SXR) diagnostic has been developed for the National Spherical Tokamak Experiment. The new edge ME-SXR system tested on NSTX consists of a set of vertically stacked diode arrays, each viewing the plasma tangentially through independent pinholes and filters providing an overlapping view of the plasma midplane which allows simultaneous ...

Annual target: Predicting the magnitude and scaling of the divertor heat load width in magnetically confined burning plasmas is a high priority for the fusion program and ITER. One of the key unresolved physics issues is what sets the heat flux width at the entrance to the divertor region. Perform massively parallel simulations using 3D edge kinetic and fluid codes to determine the parameter de...