Implosion Dynamics and Instability Growth of Double and Triple Gas-Puff Z-Pinches with and without Axial Magnetic Fields on COBRA

Gas puff Z-pinches are powerful sources of intense X-rays that generate high energy densities and temperatures with potential applications in thermonuclear fusion. However, Magneto Rayleigh Taylor Instabilities (MRTI) present a significant challenge in achieving a stable pinch. MRTI can be mitigated through tailored density profiles and an external pre-embedded axial magnetic field. Previous work using the multiphysics radiation-MHD code HYDRA has shown that higher-atomic-number inner and outer liners generally improved fuel compression and neutron yield in triple gas puffs, except when changing the inner liner from Argon to Krypton [1]. In this experiment, we utilized a triple nozzle gas injector on the COBRA (~0.9MA, 220ns on long pulse mode) driver to study the implosion dynamics and MRTI growth of Neon, Argon, and Krypton inner and outer liners with a Xenon doped H2 target with and without a 0.3 Tesla magnetic field. The plasma dynamics were characterized using an XUV framing camera, filtered soft X-ray photodiodes, a Mach-Zehnder interferometer, a laser shearing interferometer, and an X-ray spectrometer. Experimental results and comparison with MHD simulations will be presented at the meeting.

Sources: [1] J. Narkis, F. Conti, and F. N. Beg., Phys. Rev. E 105, 045205 (2022).