FF-1 tops its previous 'personal best' record for fusion yield, achieves nearly I5 scaling with current
We are happy to report that FF-1 achieved a new record with the production of 150 billion neutrons in two shots on October 10. For some time during the recent post-upgrade shakedown, the device had not produced over 100 billion neutrons (1011) repeatably, but this plateau has now been left behind with six shots over this level in two days of firing.
Equally important, the fusion yield has increased in the most recent shot series as I4.7, very close to the I5 scaling that LPP’s theory predicts (figure 1). The scaling of fusion yield with current is an extremely important indicator of whether FF-1’s functioning is getting closer to demonstrating the scientific feasibility of Focus Fusion. Energy input increases roughly as I2, where I is the current, so with output energy scaling at I4.6, it shows that the ratio of energy output to energy input is increasing rapidly as the input energy is increased. While there remains room for improvement, this is very good news!
The highest current shots of the promising new results were obtained when the LPP research team decided to raise the firing voltage while only using 8 capacitors, to better compare the new, higher current data with that obtained in May, when 8 capacitors were also used. This step from 35kV up to 40 kV will prepare the way for moving up to 45 kV, the highest voltage obtainable with the current device. Once the scaling of the fusion yield with the current is thoroughly understood with 8 capacitors, the team will return to further explore the high-pressure regime first explored last month, using all 12 capacitors. Improvements to FF-1’s ceramic “hat” insulator and related alignment capabilities are now ongoing, with firing expected to resume within a week.