On the Structure of Plasma Jets in the Rotating Plasma Experiment

Recent pulsed-power experiments have demonstrated the formation of astrophysically relevant, differentially rotating plasmas. Key features of the plasma flows are the discovery of a quasi-Keplerian rotation curve, the launching of highly collimated angular-momentum-transporting axial jets, and a hollow density structure sustained by the centrifugal barrier effect. In this communication, we discuss several features of the plasma structure in these experiments through order-of-magnitude models. First, we show that the observed rotation velocity would produce a centrifugal force strong enough to support the hollow density profile. Second, we show that the axial jet should diverge much faster than what was observed, were it not for a magnetized halo with 3 T which surrounds the jet and exerts pressure on the interface. Finally, we discuss the temperature structure in the axial jet and plasma halo. We show that a
$3$
-T magnetic field would also suppress electron heat conduction, leading to the flat profile observed experimentally. We also find that the axial jet is efficiently radiatively cooled, whereas the halo is not, which would explain the thermal decoupling between the two regions.