I have seen various reasons given for why “it won’t work”. For one thing, it’s my understanding that the prevailing view of the DPF is still that it achieves fusion primarily through the ion beam colliding with colder gas in the vacuum chamber. There are still unknowns, but in this case I think LPP has sufficiently demonstrated that the plasmoid is the primary source of fusion reactions. Losses due to bremsstrahlung (X-radiation produced by high-energy electrons decelerating in the presence of ions) is a reason given for why aneutronic fusion in general will never be an efficient energy source. Eric Lerner has a hypothesis that under certain conditions the DPF can achieve gigagauss magnetic field strengths, greatly reducing energy transfer from the ions to the electrons, in turn reducing bremsstrahlung. See here for Lerner’s argument of why FF-1 [em]will[/em] work.
Those are the main arguments I’ve seen for why the physics won’t work out. I can’t think of any others off hand. I’ve also seen arguments questioning whether the engineering will work out, especially with regard to conversion of the ion beam or X-rays to electricity, and also the rate of anode erosion.
Francisl wrote: How can that hypothesis be tested?
FF-1 needs to be run under the requisite conditions, with hydrogen-boron fuel and smaller, beryllium electrodes. That’s what we’re all waiting for.