Neutron spectra from beam-target reactions in dense Z-pinches

Journal Article · Thu Oct 15 04:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4933117· OSTI ID:22486441

Chittenden, J. ^[1]

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1. Centre for Inertial Fusion Studies, The Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)

The energy spectrum of neutrons emitted by a range of deuterium and deuterium-tritium Z-pinch devices is investigated computationally using a hybrid kinetic-MHD model. 3D MHD simulations are used to model the implosion, stagnation, and break-up of dense plasma focus devices at currents of 70 kA, 500 kA, and 2 MA and also a 15 MA gas puff. Instabilities in the MHD simulations generate large electric and magnetic fields, which accelerate ions during the stagnation and break-up phases. A kinetic model is used to calculate the trajectories of these ions and the neutron spectra produced due to the interaction of these ions with the background plasma. It is found that these beam-target neutron spectra are sensitive to the electric and magnetic fields at stagnation resulting in significant differences in the spectra emitted by each device. Most notably, magnetization of the accelerated ions causes the beam-target spectra to be isotropic for the gas puff simulations. It is also shown that beam-target spectra can have a peak intensity located at a lower energy than the peak intensity of a thermonuclear spectrum. A number of other differences in the shapes of beam-target and thermonuclear spectra are also observed for each device. Finally, significant differences between the shapes of beam-target DD and DT neutron spectra, due to differences in the reaction cross-sections, are illustrated.

• OSTI ID: 22486441
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 10 Vol. 22; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAMS
COMPUTERIZED SIMULATION
CROSS SECTIONS
DEUTERIUM
ENERGY SPECTRA
IMPLOSIONS
IONS
LINEAR Z PINCH DEVICES
MAGNETIC FIELDS
MAGNETIZATION
MAGNETOHYDRODYNAMICS
NEUTRON SPECTRA
PLASMA
PLASMA FOCUS DEVICES
STAGNATION
TRAJECTORIES