Spectroscopic investigation of plasma-material interactions on the ZaP-HD sheared-flow-stabilized Z-pinch device

High energy density plasma-material interactions occur on the ZaP-HD sheared-flow-stabilized Z-pinch device. In particular, erosion of the graphite cathode contributes to impurity production and limits the lifetime of the component. Understanding the plasma-electrode interaction is critical for ongoing work in scaling the concept to a reactor device and the associated increase in energy density. Spectroscopic methods provide in-situ, non-perturbing measurements of various parameters in this extreme environment. A fast-framing camera coupled to a Czerny-Turner spectrometer provides time-resolved relative intensity measurements of impurity ions over a range of spatial locations. These can also be used to calculate plasma temperature and velocity near the cathode. In addition, a CCD camera and PMT provide a time-integrated spectrum and time-resolved intensity respectively for a single impurity line. Together, these instruments characterize the spatiotemporal distribution of impurity ionization stages. These results will support implementation of the ionizations per photon (S/XB) method to infer sputtered impurity flux.