Helium jet spectroscopy in the divertor region of C-2W

TAE Technologies’ current experimental device, C-2W (also called “Norman”), is an advanced, neutral beam-driven, field-reversed configuration (FRC), which utilizes edge control by means of electrode biasing to stabilize the FRC. [1] Applied potentials at the boundary generate radial electric fields which affect plasma rotation in open field lines due to azimuthal ExB drift. A recently deployed supersonic helium gas injector provides target impurities and a promising opportunity for spectroscopic measurements in the divertor region of C-2W. A high-resolution spectrometer was utilized to measure the Doppler shift of target helium transitions and infer radial electric fields from the temporal evolution of azimuthal velocities. These measurements can help validate axial electrostatic potential and circuit models under development at TAE. Experimental design details and diagnostic capabilities will be presented and discussed.

1. H. Gota et al., Nucl. Fusion 61,106039 (2021)