Lawrenceville Plasma Physics – LPP research team members Aaron Blake and Derek Shannon designed a more robust substitute for the pins—a serrated ring of tungsten, with the saw tooth points substituting for the points of the pins. We also have located a much larger machine shop which uses electrical discharge machining (EDM), a highly precise method of machining with intense electric current.
We now expect the new shop to complete the new cathode plate by early April, allowing us to resume firing, confident that we will have a highly symmetric set of electrodes. This symmetry is essential to achieving good compression of the plasma and producing higher fusion yields.
Over 150,000 electron volt ions and over 1.8 billion degrees
Using a dense plasma focus device with a 50 kJ capacitor charge, we have observed fusion reactions from deuterium ions with record energies of over 150 keV, which are confined for durations of 7–30 ns in the cores of plasmoids with typical radii of 300–500 μm and densities ∼3 × 10^19 cm−3. We have for the first time simultaneously imaged the plasmoid at high (30 μm) resolution and measured trapped ion energy and neutron anisotropy. The isotropy of the neutron emission as well as other observations confirms that the observed neutrons per pulse of up to 1.5 × 10^11 are produced mainly by confined ions, not an unconfined beam. The conditions achieved are of interest for aneutronic fusion, such as with pB11 fuel.