Experimental Dependence of the Neutron Yield on the Discharge Current for Plasma Focus Chambers Filled with Deuterium and Deuterium–Tritium

• Published in: Plasma physics reports 2019-04, Vol.45 (4), p.334-344
• Main Authors: Mikhailov, Yu. V., Lemeshko, B. D., Prokuratov, I. A.
• Format: Article
• Language: English
• Subjects: Anisotropy; Atomic; Beamforming; Chambers; Dependence; Deuterium; Discharge; Energy measurement; Molecular; Neutron emission; Neutrons; Nuclear reactions; Optical and Plasma Physics; Physics; Physics and Astronomy; Plasma focus; Plasma Radiation; Tritium
• ISSN: 1063-780X; 1562-6938
• DOI: 10.1134/S1063780X19030073

Results of measurement of the mean neutron yield from plasma focus (PF) chambers filled with deuterium and deuterium–tritium are compared for various Mather-type and spherical PF devices at discharge currents in the range of 200−1000 kA. On the basis of the experimental results, an expression for the ratio of the neutron yields in the D + T and D + D reactions as a function of the discharge current is derived, according to which ξ exp decreases from 150 to 110 (by ≈1.4 times) as the PF discharge current increases from 200 to 1000 kA. Assuming the beam–target mechanism of neutron generation in the PF, the ratio ξ exp for D + T and D + D reactions is compared with the ratio σ DT /σ DD of the cross sections for the corresponding nuclear reactions at different mean energies of accelerated ions. Taking into account the mean energies of accelerated ions (~50–70 keV) determined from the measured space–energy anisotropy of neutron emission, it is suggested that the mean effective energy of accelerated D + and T + ions in the plasma beam formed in the pinch decay stage increases with increasing PF discharge current, which leads to a decrease in the ratio with increasing current.