A study of disk-jet transitions using pulsed-power generators*

Astrophysical plasma jets are ubiquitous structures formed by a variety of sources.  These jets may range in length from hundreds to millions of AU while maintaining the same overall geometry.  Equally intriguing is their radius, which can be thousands of times smaller than their length.  Yet such narrow, extended structures are clearly turbulent. Most jets are powered by a gravitational engine, which redirects infalling matter from the accretion disk outward along the axis of rotation of the disk.  In this study, we use high energy density plasmas to generate accretion disks and observe how radial flows transition into outward jets.  While gravity has been replaced by inward JxB forces, our setup shares similarities with its astrophysical counter-part: flows are supersonic, turbulent, advect magnetic fields in their wake, and radially fall inwards.  The rotating accretion disk is generated by running 1MA of current inside thin wires distributed azimuthally around the accretion disk axis.  Disk rotation is controlled by forcing the ablated plasma flow inward, and the jet is magnetized by an axial magnetic field. We will look at the impact of this magnetic field on jet formation.