Preliminary Evidence of High-Energy Ions

The evidence was obtained on a single shot on January 8. This shot was with 10 torr of deuterium in the vacuum chamber, by far the highest pressure for which we have good data with the FTF detector. LPP’s theory predicts that higher gas densities will lead to higher temperatures within the plasmoid. In this shot the bank produced 0.56 MA at 30 kV, well below its ultimate potential.

We deduced this energy from the timing of the X-ray and neutron pulses observed by the FTF. (See figure 1). The first very sharp peak is the X-ray pulse, caused by radiation from hot electrons in the plasmoid and arriving at the FTF at the speed of light, 30 cm per ns. The second group of peaks is the neutrons, traveling much slower and arriving later. We know that the neutrons are produced by DD fusion reactions and should have a velocity of 2.2 cm per ns and should arrive 719 ns after the X-rays. We also know that the fusion reactions only occur once the electrons have heated up the ions.


Figure 1. The X-ray pulse (left) and neutron pulse (right) from shot 1/09/10-05 as recorded on the FTF. Vertical axis is in volts, horizontal in nanoseconds. (Signal has been attenuated 10 times).

But in this shot (1/08/10-05) the first burst of neutrons arrives only 682 ns after the beginning of the X-ray pulse. These neutrons, traveling faster than would be expected from the fusion energy alone, must have additional energy imparted to them by the motion of the nuclei that collided to produce the reaction. From this data we can deduce that the average ion in the plasmoid has at least 45 keV of energy. If the neutrons actually originated later in the pulse, then they traveled faster and the average ion energy could have been higher.

Once we have the Near Time of Flight (NTF) working, we will be able to more directly measure the velocity of the neutrons by timing when they pass the NTF and then the FTF. The X-ray pulses are evidence of high electron energies as well, since at the moment, the X-ray window is blocked with a ¾” steel plate. X-rays must have energies above about 100 keV to get through the plate in substantial numbers, implying hot electrons as well as hot ions were produced in this and several other shots with similar X-ray pulses. However, in the other pulses at lower pressures (3-4 torr), the ions did not heat up to high temperature, due to the lower density in the plasmoid.

For comparison, we observed ion temperatures of 55-100 keV at Texas and 100 keV is adequate to start pB11 fusion reactions.

As yet, the number of fusion reactions achieved are modest—7.3 x10⁸ neutrons in this shot, 6x10⁹ neutrons with the maximum shot, only 5 mJ of fusion energy. We expect this yield to grow rapidly over the next few months.