LPP Fusion Technical Milestones in 2018:
Completed experiments with tungsten electrodes
Observational confirmation of the destruction of filaments
Publication of cosmology results in leading journal—Monthly Notices of the Royal Astronomical Society
LPP Fusion Non-Technical Milestones in 2018:
Over $950,000 investments from Wefunder
Over $300,000 gift to Focus Fusion Society for aneutronic fusion research
EU patent granted
Founding of Fusion Industry Association
Successful LPPF financial audit
Reducing Inpurities, Increasing Plasma Density
The basic LPP Fusion plan is to increase the density of the plasmoid and thus the fusion yield by greatly reducing the heavy-metal impurities. So let’s answer some questions about this plan.
1) First, why do we think that reducing heavy-metal impurities will increase fusion yield? LPP Fusion has solid experimental evidence for this hypothesis. Over the history of the FF-1 experimental device, whenever we reduced impurities, yield went up. Whenever they failed to reduce impurities, yield did not rise and whenever they inadvertently increased impurities, yield went down. For example, back in 2011, a badly fitted part created heavy arcing inside the vacuum chamber, releasing large amounts of vaporized copper and steel impurities into the plasma. Fusion yield plunged all the way down to zero. This was the first big clue that led us to believe impurities were a key problem. When they fixed the arcing, and impurities went down, yield went back up.
2) How much yield increase does LPP Fusion expect initially, if they do decrease impurities?
The dense plasma focus device (DPF), for solid physical reasons, has a fusion output that increases sharply with electrical current—approximately as current to the fifth power. In other words, if current goes up by 2, yield goes up by 25 or 32. This scaling law, which works for smaller DPF devices, has been interrupted for larger ones—they don’t get the yield expected from the scaling law. They think that is due to the larger impurities that powerful DPFs have produced. They anticipate that with low impurities their initial experiments with pure deuterium should get our fusion yield up from about ¼ J—LPP Fusion’s best result with tungsten electrodes—to over 2 Joules.
Why are they confident that in this experiment they will radically reduce heavy impurities?LPP Fusion is eliminating, almost entirely, all heavy metals from the experimental chamber.
There are both strong theoretical reasons and abundant experimental evidence that impurities affect plasma characteristics, such as electrical resistivity, in proportion to the product fz2, where f is the fraction (by number) of ions with an atomic charge z. They are switching our electrodes from tungsten, with a z of 74, to beryllium, with a z of 4. This means that, when fully ionized, each beryllium ion in the plasma has 340 times less effect than each tungsten ion. They don’t expect a lot more beryllium ions to be vaporized, because the energy to vaporize and ionize one beryllium ion is already ¾ the energy needed for one tungsten ion. So the contribution of the electrodes to impurities will be hundreds of times less in the new experiment.