Study of Multi-Shell Gas Puff Z-Pinches with and without Axial Magnetic Field*

Gas Puff Z-Pinches are a well-studied source of high energy density plasmas and a promising candidate for nuclear fusion [1]. The growth of the Magneto Rayleigh-Taylor Instability (MRTI), however, limits its prospects as a reliable fusion concept. The application of a pre-embedded axial magnetic field can mitigate this growth, but simulations predict it also causes a decrease in the plasma temperature achieved at stagnation [2]. To combat this effect, multiple annular gas puff shells can be used with lower axial magnetic field strengths to mitigate MRTI growth. Experiments conducted on the 1MA, 200ns rise time COBRA generator at Cornell University investigated the combined effects of these mitigation techniques. Time gated XUV images captured the growth of the MRTI during the implosion, and X-ray spectroscopy provided data on the peak plasma temperatures. Simulations from the collisional-radiative spectral analysis code PrismSpect were compared to experimental spectra to determine the plasma parameters. Results of this analysis will be presented.

[1] J. L. Giuliani and R. J. Commisso, IEEE Transactions on Plasma Science 43, 2385 (2015).

[2] J. Narkis et al., Phys. Rev. E 104, L023201 (2021).