We Have Ignition!

So the big news of the week, which was preceded by the rumors a few days before the official announcement, is the breakeven achievement in a fusion process at Lawrence Livermore's National Ignition Facility (NIF).

This is certainly a major breakthrough, and it is something that has achieved for the very first time ever in a controlled experiment (it happens all the time in our Sun and other stars). However, to me, this is more of a proof-of-principle experiment, meaning that it is a demonstration that it is possible, rather than to show that it is viable. It is certainly very, VERY far away from producing anything useful because harnessing this energy is an entirely different matter.

While you can read many sites reporting this, I kinda like the one that I read on CNET because there's a certainly level of sensibility aimed towards the general public. In particular, there is this definition of what is meant by "breakeven":

More specifically, scientists at NIF kickstarted a fusion reaction using about 2 megajoules of energy to power the lasers and were able to get about 3 megajoules out. Based on the definition of ignition used by NIF, the benchmark has been passed during this one short pulse. 

But that doesn't convey the whole thing, because this is what should also be mentioned:

"The calculation of energy gain only considers the energy that hit the target, and not the [very large] energy consumption that goes into supporting the infrastructure," said Patrick Burr, a nuclear engineer at the University of New South Wales.

What it means is that they only considered the energy of the laser hitting the target, and then finding the energy output from the ignition that subsequently resulted in fusion. Sure, that energy output is greater than the input energy of the laser, but this is not the total energy of the entire facility that created the laser. That facility would still not be self-sufficient to run just by using the output energy of the fusion it created, even assuming 100% efficiency.

This does not diminish the amazing achievement, considering that other facilities and techniques have not even reach this level. It is just that it needs to be tampered with a bit more realistic expectations so that we don't oversell ourselves to the public.

Zz.