Different stabilization processes in Z-pinch plasma experimental approch

We are investigating several methods to stabilize an aluminum vapor Z-pinch involving; applied axial magnetic fields, decreased z-current rise-time, and staged loads. The pinch is driven by a 2 Ω, 0.1 TW generator (∼250 kA in ∼50 ns) and is initiated in a plasma jet (3-mm diameter and 9-mm long) prepared by an exploded aluminum foil (5-mm thick). The axial-magnetic field is externally applied (Bzo ∼ 50 G) or alternately, self-generated by a twisted discharge-return-current structure (Bzo <1 kG). The current risetime is decreased by a plasma opening switch (POS) located in the vacuum current feed, upstream of the pinch. The staged load involves a standard pinch imploded onto coaxial targets of conducting or nonconducting wires, i.e. plasma on wire (POW). Diagnostics include: framing/streak camera, filtered PIN XRDs, PET crystal spectrometer, multi-pinhole x-ray photos. Qualitatively, the stability improves with an axial field and the x-ray yield is greater with a self-generated field (twisted return-current structure). With a plasma load the POS reduces the prepulse, sharpens the current rise-time and improves the x-ray yield. Overall the POW configuration is associated with the best stability and highest radiation yields.