Nuclear reaction kinetics in deuterium gas puffs

Summary form only given. We present the results of a computational investigation of nuclear reaction kinetics in deuterium gas puffs. Deuterium gas puffs are the largest source of laboratory neutrons producing more than 10¹³ neutrons on the Z machine at Sandia National Laboratories. However, the mechanisms producing these neutrons are poorly understood. These mechanisms include thermonuclear production and production by high energy deuterons accelerated by large E fields. Understanding the significance of each mechanism is important for determining the scalability of the results to higher currents. We use a hybrid PIC-MHD model to investigate these effects. The gas puff implosion is simulated hydrodynamically using the 3D MHD GORGON code and non-thermal neutron production is modelled by the addition of a kinetic species. Results show that non-thermal neutron production makes up a small fraction of the total neutron production. Neutron energy spectra are computed from the model and compared with analytic predictions. The model is also used to calculate the number of 14.1 MeV neutrons produced by secondary DT reactions. The ratio of secondary to primary neutrons is approximately 0.0001.