Characterization of Quasi-Keplerian, Differentially Rotating, Free-Boundary Laboratory Plasmas

We present results from pulsed-power driven differentially rotating plasma experiments designed to simulate physics relevant to astrophysical disks and jets. In these experiments, angular momentum is injected by the ram pressure of the ablation flows from a wire array Z pinch. In contrast to previous liquid metal and plasma experiments, rotation is not driven by boundary forces. Axial pressure gradients launch a rotating plasma jet upward, which is confined by a combination of ram, thermal, and magnetic pressure of a surrounding plasma halo. The jet has subsonic rotation, with a maximum rotation velocity 23 +/- 3 km/s. The rotational velocity profile is quasi-Keplerian with a positive Rayleigh discriminant kappa 2 proportional to r-2.8 +/- 0.8 rad2/s2. The plasma completes 0.5-2 full rotations in the experimental time frame (similar to 150 ns).

Automated summary

We conducted pulsed-power driven plasma experiments to simulate astrophysical disks and jets. Angular momentum is injected by ablation flows from a wire array Z pinch, rather than boundary forces. An upward rotating plasma jet is launched by axial pressure gradients and confined by ram, thermal, and magnetic pressure. The jet has a subsonic rotation with a maximum velocity of 23 +/- 3 km/s, following a quasi-Keplerian profile with a positive Rayleigh discriminant kappa 2 proportional to r-2.8 +/- 0.8 rad2/s2. The plasma completes 0.5-2 full rotations within the experimental time frame (approximately 150 ns).