From the comments, on a fusion reactor
So for once I can intelligently comment on a Marginal Revolution article. (I have a Ph.D. in applied plasma physics and fusion energy; I worked on the “conventional” fusion reactor design, the tokamak). Lockheed hasn’t released many details of their concept (at least, not enough details that it can actually be evaluated in technical detail), but it looks like it’s a combination of a magnetic mirror and a levitated dipole. The magnetic mirror was studied in detail in the 1960s and 1970s and didn’t work out (due to [detailed plasma physics reasons]) and the levitated dipole has a fundamental flaw as a power-producing reactor in that the superconducting magnets are inside the neutron shielding – neutrons destroy the magnets.
It’s tough as a scientist to be able to comment on things like this, because it’s “science by press release”, i.e. there’s a big media hype but the actual researchers don’t release enough technical details to actually evaluate it. One wants to remain cautiously optimistic, but with fusion in particular, we’ve been down this road many, many times. Thus I predict that the most likely outcome is that as they scale their device up, they’ll find that the confinement (a measure of how well the device holds a fusion plasma) unexpectedly drops off due to some different types of turbulence turning on at higher temperatures / higher pressures… and it will quietly go away.
I hope that I am proven wrong.
There are other interesting comments at the link and Kottke offers more.