Probing plasma conditions on the sheared flow stabilized Z-pinch using Optical Thomson Scattering at Zap Energy

ARPA‐E supports the investigation and development of potentially transformative fusion‐energy

concepts. Spatially and temporally resolved measurements of plasma parameters greatly benefit these fusion experiments by establishing the level of performance that has been achieved. Thomson scattering is a diagnostic technique capable of locally probing plasma parameters including electron density, electron temperature, ion temperature, and flow velocity. We have designed and deployed an optical Thomson scattering system to investigate plasma parameters on the sheared-flow-stabilized Z pinch at Zap Energy. Scattering of a 532 nm, 1.6 ns, 8 J Nd-YAG probe laser is collected from 17 points within the plasma column and delivered by a fiber bundle to a spectrometer with gated CMOS cameras. We report on electron densities and temperatures measured on the sheared flow stabilized Z pinch. We discuss their temporal evolution with respect to the quiescent period of the plasma when fusion neutrons are produced. This work is funded under ARPA-E Cooperative Agreement DE-AR0001165 and prepared by LLNL under Contract DE-AC52-07NA27344, LLNL-ABS-836808.