Correlation of Radiation and Electron and Neutron Signals at PF-1000

Abstract

At the signals of x‐rays usually 2 peaks were observed. The first peak corresponded to the time of the minimum diameter of the imploding plasma sheath (pinch phase) recorded by the visible frames. The second peak occurred 150–200 ns later at the time of the development of instabilities. High‐energy electrons registered in the upstream and downstream directions differed in the intensity (ratio 3:1) and in the time of production. Their peaks correlated with x‐rays. The energy of neutrons and time of their generation were determined by time‐of‐flight method from the pulses of seven scintillation detectors positioned in the axial direction. At the rise‐time, each neutron pulse has registered downstream energies in range of 2.7–3.2 MeV. The final part of neutron pulse has isotropic energy distribution with energies up to 2.6–2.7 MeV. The evolution of the neutron pulses correlates with the visible frames. The first pulse correlates with the fast downstream zipper‐effect of the dense plasma in the pinch and with the forming of the radiating ball‐shaped structure at the bottom of the dilating plasma sheath. The second neutron pulse correlates with the second pinching and exploding of the plasma of lower density and with existence of the structure of the dense plasma positioned at the bottom of the dilating current sheath, similarly to the first pulse. The neutrons have a non‐thermal beam‐target origin. A possible influence of the zipper‐effect on the acceleration of deuterons and on the plasma heating is discussed.