Simulations of a dense plasma focus with characterization of the neutron emission

Abstract

We present 3D MHD simulations of a 100kA deuterium filled dense plasma focus, carried out using the Gorgon MHD code. The simulations model the entire implosion from the run down phase to the pinch phase and accompanying neutron production.The electromagnetic fields that are generated in the plasma during the pinching phase are used in a hybrid (kinetic-fluid) code to model the non-thermal ion population produced by the plasma focus. Large electric fields accelerate ions to high (>100 key) energies. The hybrid code calculates fusion reactions between thermal and non-thermal ions and models the resulting neutron emission spectra. The shape of these neutron spectra are analyzed and related to the underlying plasma conditions. In particular, the degree of magnetization of the accelerated ions and the mean energy of accelerated ions can be determined from the neutron spectra. Comparisons are made with simulations of 13MA double shell deuterium gas puffs in which the neutron spectra produced by beam-target reactions are near-isotropic with broad FWHM due to the high level of magnetization of ion beams produced in the gas puff.