High-fidelity inference of local impurity profiles in C-2W using Bayesian tomography.

In C-2W (also called "Norman") [1], beam-driven field reversed configuration plasmas embedded in a magnetic mirror are produced and sustained in a steady state. A multi-chord passive Doppler spectroscopy diagnostic provides line-integrated impurity emission measurements near the center plane of the confinement vessel with fast time resolution. The high degree of plasma non-uniformity across optical sightlines can preclude direct fitting of the measured line-integrated spectra.

Upgraded main ion charge exchange recombination spectroscopy on the C-2W field reversed configuration (FRC) plasma.

A prototype main-ion CHarge Exchange Recombination Spectroscopy (mCHERS) diagnostic is providing measurements of the main-ion (hydrogen or deuterium) temperature and velocity in the C-2W field reversed configuration plasma using charge exchange Balmer-alpha emission at five different radial locations with 500 Hz frequency and a per-pixel velocity resolution of 15 km/s. Measurement along the entire plasma radius of C-2W is enabled by a diagnostic neutral beam (DNB) that passes through the center of plasma, unlike the larger diameter heating neutral beams that have impact parameters of 20 cm. DNB provides high time resolution via beam modulation and spatial resolution via its small cross section.

Main ion charge exchange recombination spectroscopy on C-2W FRC plasmas.

A main ion charge exchange recombination spectroscopy (mChERS) diagnostic has been developed to measure the velocity and temperature of the main deuterium ions in the C-2W (also called Norman) field-reversed configuration (FRC) device. A modulated diagnostic neutral beam (DNB) of hydrogen with 40 keV full energy and a nominal current of 8.5 A provides the charge exchange signal.

Measurements of impurity ion temperature and velocity distributions via active charge-exchange recombination spectroscopy in C-2W.

In TAE Technologies' C-2W experiment, electrode biasing is utilized for boundary control of a field-reversed configuration (FRC) plasma embedded in a magnetic mirror. Understanding the underlying physics associated with FRC rotation, stabilization, and heating is crucial for improving machine performance. Impurity ion rotation and temperature are sensitive to biasing effects, and measurements of these quantities can provide insight into important plasma dynamics and overall effectiveness of the biasing system.