LPP Fusion has submitted a paper for peer review to the journal Physics of Plasmas, in which Lerner and his coauthors claim to have produced a confined mean ion energy of 200 kiloelectron volts, equivalent to a temperature of over 2 billion kelvins. “As far as we know, that’s a record for any fusion plasma,” Lerner says.
“In the critical measure of how much energy out we get per unit energy in, we’re No. 2 among all the experiments in the world,” Lerner says. “And we’re only one-third behind the JET [Joint European Torus] experiment in the United Kingdom—which has almost a thousand times our resources. In terms of results per unit dollar, we’re clearly No. 1, by a long way.”
They are cleaning Tungsten electrode impurities from a chamber and moving to being Beryllium electrodes soon which will not have impurity problems
Based on tests conducted in May, the LPPFusion research team decided that more microwave power was needed to clean the oxides off our tungsten electrodes. The oxides, which break up easily when heated, had been contributing impurities to the plasma and limiting fusion yield. We decided to mount two kW microwave magnetrons on a single large window to double the power. The larger window admitted the 12-cm-long waves far more efficiently than a smaller window used with the second magnetron in May. Combining the two magnetrons proved to be fairly difficult, because the two magnetrons, working independently, could cancel out each other’s waves.
First Dr. Hassan made a copper, v-shaped combiner to couple the two magnetrons. Then, based on that experience and papers published by other groups, the team designed an aluminum coupler with a “trombone tuner” that could adjust the coupling of the waves between the two magnetrons. That combiner, fabricated at local shops, worked well and nearly doubled total power output. After some experimentation, the team was able to use the combiner to create more intense plasma heating.
Once the present series of experiments with the tungsten electrodes is completed, the FF-1’s vacuum chamber will be disassembled and shipped for a recoating with titanium nitride. This stable material will cover up any tungsten that has been plated onto the chamber. This and other upgrades to FF-1 will take a few months, leading to the start of new experiments with the beryllium electrodes around year-end.