Correlation of x-ray emission with interferometry and neutron diagnostics at tungsten anode face and deuterium filling in plasma-focus discharge

Abstract

In this paper, the influence of the tungsten evaporated from the anode on neutron production and soft x-ray radiation was studied on the base of x-ray, interferometry and neutron diagnostics performed on the plasma-focus PF-1000 device with deuterium as the filling gas at the current of 2 MA and neutron yield above 10 10 . In the axial center of the anode face the copper circuit plate was substituted with a tungsten one. During the pinch, the tungsten ions evaporated from the anode were transported into the plasma column. The differences in the filters used in the microchannel-plate detector X-frames and PIN detectors enabled separation of the bremsstrahlung emitted by the deuterium plasma from the recombination radiation of the tungsten ions produced in the region of the plasma column near the anode at the time of the evolution of instabilities. In comparison with the copper anode face, the neutron yield decreased to 40% and the energy of deuterons producing neutrons to 80%.

Influence of the external magnetic field on pinch evolution and neutron production in plasma-focus discharge

“…The conductivity depends on the electron temperature. It can be estimated from the Spitzer formula [18] for the range of electron temperatures above 10 eV as γ > 4×10 4 Si/m. Then, the resulting time of dissipation is above 400 ns.…”

“…The magnetic energy contained in the constrictions and plasmoids is released during their formation and expansion or decay, and it can contribute to the acceleration of fast deuterons and electrons. In paper [18], the influence of the admixtures evaporated from the anode face (in which the copper was substituted with tungsten) on x-ray emission, on the evolution of the internal structures in the pinch and on the neutron production was presented. These admixtures decrease the velocity of transformations and neutron production.…”