Upgraded Diagnostic Array for End Losses from C-2W's Open Field Line Plasma

In TAE Technologies’ current experimental device, C-2W (also called “Norman”) [1], the FRC core plasma is surrounded by a mirror-confined scrape-off layer plasma on open field lines. An upgraded array of energy analyzers and bolometers has been installed in the divertors of C-2W to measure axial power losses as well as the electron temperature and ion energy distribution function (IEDF) of the plasma at the termination point of the open field lines. The previous system measured a strong ambipolar potential (~4.5 T_e) along the open field lines, and value for the energy lost per ion, η_e, of 6-8, indicating good electron heat confinement [2]. The new system has improved radial and azimuthal coverage to investigate two-dimensional effects of open-field-line electron confinement. Design and preliminary measurements will be presented.

[1] H. Gota et al., Nucl. Fusion 59, 112009 (2019)

[2] M. Griswold et. al. "Measurement of Axial Plasma Losses in the C-2W High Performance Regime" Poster Presented at the 61st Annual Meeting of the APS-DPP (October, 2019)