Ion temperatures inferred from neutron yield measurements in the TRISOPS IIX plasma vortex structure generator

Abstract

The ion temperature history of the plasma fireball in TRISOPS IIX has been measured by comparing the time-resolved neutron yield from a D–D reaction and a D–T reaction. This measurement results in a reading of ion temperature that is independent of any assumptions of plasma density or fireball volume. The results verify and clarify previously reported TRISOPS parameters. In a separate set of measurements using a D–D reaction, the ion temperature was determined by comparisons of Doppler broadening and neutron yield. It was found that the ion temperature rises in 5 μs to 6 keV with a corresponding density of 1015 ions cm3. After 8 μs it falls rapidly to 1 keV as the density rises to 1017 ions cm–3. The 1 keV temperature is held for about 20 μs. These temperatures and densities yield an equilibration time for ions and electrons that is long compared with the duration of the experiment.