Measuring $\sim$10~T B-Fields Using Zeeman Splitting of Sodium Emission Lines on a 500~kA Pulsed Power Machine*

Following earlier work by M. Gomez \textit{et al.} [1], we have shown that Zeeman splitting of the Sodium (Na) D-lines at 5890~{\AA} and 5896~{\AA} can be used to measure the magnetic field (B-field) produced in high current pulsed power experiments. In the present experiments, we have measured the B-field next to a return current post during hybrid X-pinch experiments near peak current. These measurements were performed at 500~kA current on the XP machine at Cornell University using a 150~ns current rise time. Na was added to the system by applying a few drops of a NaCl solution onto the inner surface of one of two 4~mm radius return current posts, located about 4~cm away from the hybrid X-pinch. The Na is desorbed from the return current post by radiation from the hybrid x-pinch, enabling observation of the Na vapor's spectral lines. Measurements have shown a B-field of 10-15~T near the return current post, which is consistent with the calculated B-field. Future experiments will explore applying this approach to regions of higher B-field in higher current machines.\\[4pt] [1] M. R. Gomez, \textit{et al.} Rev. Sci. Instrum. \textbf{85}, 11E609 (2014)