Effect of Initial Conditions on Charged Particle Acceleration in a Dense Plasma Focus

• Main Authors: Jackson, S. L., Engelbrecht, J. T., Beresnyak, A. R., Mamonau, A.A., Petkov, E. E., Richardson, A. S., Allen, R. J., Boyer, C. N., Giuliani, J. L., Schumer, J. W., Klir, D., Rezac, K., Cikhardt, J., Maron, Y., Stambulchik, E., Roark, Christine, Stoltz, Peter H., Spirkin, Anton, Luginsland, J. W.
• Format: Conference Proceeding
• Language: English
• Subjects: Atmospheric measurements; Energy measurement; Linear particle accelerator; Magnetohydrodynamics; Neutrons; Particle measurements; Plasma measurements
• ISSN: 2576-7208
• DOI: 10.1109/ICOPS37625.2020.9717552

Charged particle acceleration has been investigated in a dense plasma focus (DPF) driven by the Hawk pulsed-power generator at the Naval Research Laboratory. Neutron yields of over 5.0\times 10^{10} have been measured at a peak current of \mathrm{I}=670\text{kA} ) significantly above the yield expected at this current based on purely I 4.4 scaling from conventional DPFs. The high inductance (607 nH) and associated high voltage (640 kV) and fast rise time (1.2 \mu \mathrm{s}) of Hawk are unusual for a DPF driver, as is the initialization of the DPF using local injection of neutral gas and plasma into a vacuum chamber, rather than a conventional neutral gas fill. This method of initialization allows for the selection of an extensive array of initial conditions. A subset of those initial conditions has been explored in conjunction with multi-dimensional MHD simulations to affect the energy of the accelerated ions, as measured by an ion multi-pinhole camera, the neutron yield, as measured by rhodium-foil activation counters, and the end point energy of the emitted neutrons, as measured by neutron time-of-flight detectors.