Hybrid X-pinches

Abstract

Results from experimental studies of a hybrid X pinch with an initial configuration in the form of a high current diode with conical tungsten electrodes spaced by 1-2 mm and connected to one another with 20 to 100 μm diameter wires are presented. The experiments were carried out at four facilities with a current amplitude from 200 to 1000 kA and front duration from 45 to 200 ns. It is shown that, in spite of their simpler configuration, hybrid X pinches with a short rise time of the current pulse (50-100 ns) are highly competitive with standard X pinches in the generated soft X ray power and the formation of a single hot spot in them is much more stable, while hard X ray emission is almost absent. The possibility of using hybrid X pinches as soft X ray sources for point projection X ray imaging of plasma objects is considered.

Hard X-rays from hybrid X pinches

“…Hybrid X pinches have one more benefit compare with standard X-pinches (SXPs). Because the minidiode that forms when the X-ray burst occurs is closed by expanding electrode plasma, HXPs are free from the longer electron-beam-generated hard X-ray emission typical of SXPs [7]. Therefore, HXPs produce both less hard X-ray yield and less debris, the source of which is the longer electron beam.…”

“…In our previous experiments, minidiodes in HXPs were observed for 10-20 ns depending on the HXP wire material [7]. Therefore, short electron beams were observed in HXPs [7]. Spectroscopic experiments showed generation of characteristic lines radiation generated when accelerated electrons were decelerated in the plasma of the HXP wire together with electrode plasma.…”

“…Therefore, HXPs produce both less hard X-ray yield and less debris, the source of which is the longer electron beam. In our previous experiments, minidiodes in HXPs were observed for 10-20 ns depending on the HXP wire material [7]. Therefore, short electron beams were observed in HXPs [7].…”

Resolving microstructures in Z pinches with intensity interferometry

“…The spatial resolution at the target plasma is a convolution of the detector spatial resolution, the image resolution, and the system magnification. Some of the limitations of conventional pinhole imaging have been overcome by collecting x-ray slit images 16 or through translucent meshes 17 and fitting the data to wave optics calculations. These techniques have resolved micron-sized sources within X-pinches.…”

Investigation of High-Temperature Bright Plasma X-ray Sources Produced in 5-MA X-Pinch Experiments

“…The SATURN experiments extend previous work on the 1 MA, 100-ns COBRA facility [16]. We fielded several X-pinch load designs that were first evaluated on 1 MA experiments, including large wire-number cylindrical wire arrays twisted into an X-pinch [16], nested multi-layered wire arrays twisted into an X-pinch [17], and a hybrid configuration in which a single wire is strung across two conical electrodes [16,18,19]. However, most of our SATURN experiments used X-pinch loads with solid, machined cross points as shown in Fig.…”