Dynamics of hybrid X pinches

Abstract

Summary form only given. The hybrid X pinch (HXP) configuration, consisting of solid conical electrodes connected by a wire, has been studied on pulsers with current from 250 kA to 1.2 MA and current rise time from 45 ns to 170 ns1. The experiments have shown that for each generator, it is possible to find a wire material, diameter and length for which the HXP generates an intense single burst of soft x-rays and develops a single hot spot with micron size. However, the physics of the process of single hot spot formation has not been studied in detail. In order to understand the physical processes that occur in the HXPs we are carrying out an in-depth investigation of those processes and comparing them with the physics of standard X pinches (SXP). The early stages of HXP and SXP hot spot formation have been studied on the BIN (250 kA, 100 ns) and XP (400 kA, 100 ns) pulsers. Point-projection x-ray radiography with HXPs as the source of the x-ray radiation was used in most experiments2. Hybrid and standard X-pinches were placed in the return current circuit of the pulsers in place of one of the two rods. 70 kA and 120 kA current through the X pinches were measured on the BIN and XP pulsers, respectively. The experiments have shown that the early stages of standard and hybrid X-pinch hot spot formation are very different. The final stage of hot spot formation has been studied in the configuration with two HXPs placed in parallel in the full current central electrode gap. The final pinching process in the HXP is similar to the same stage of SXP. The influence of the inter electrode plasma on HXP dynamics also has been studied, and it does have a substantial effect.