While I do agree that the extended video went into hand waving arguments on few occasions, that is not because Helion may know something that general public do

While I do agree that the extended video went into hand waving arguments on few occasions, that is not because Helion may know something that general public do not, but rather because nobody knows! Helion own admission is that they use 2-d code to model the whole thing. While they validated that model with the current design, but one cannot predict how the real physics will deviate from the model at fusion condition. That adds a lot of uncertainty and, as such, skepticism as the reality can be much worse than even the hand-waving arguments from the video. For example, Helion’s patent https://patents.google.com/patent/US11469003B2/en https://patents.google.com/patent/US11469003B2/en hints how critical is suppression of the secondary D+T reactions and removal of T to their design, but patent itself does not describe how they are going to archive that. The only claim is that there would be no time for secondary D+T in their design. But that is based on those imprecise models at best. Nobody knows if that is true for sure. Plus the patent does not tell at all how they are going to remove mechanically all T after the pulse as keeping even 1% of T can be problematic. In addition the extended video cites Helion own admission that the neutron flux from D+D alone will be like 1e18 neutrons/day based on their models. That type of flux damages a lot of materials within days with slower fission neutrons. While their aluminum coils may handle that better especially if partially shielded, nobody knows for sure again as modeling effects of radiation damage is hard.