The short version is it’s a remarkable technical and scientific achievement. Controlled human-made power from fission is easy - last week marked the 80th anniversary of the first reactor. Fusion - what powers the stars - is much more difficult on Earth. The necessary temperatures are far greater than those found in most stars. A star like the Sun gets away with a very slow and low power density reaction that would be impractical for generating power on Earth. It turns out the power density of the core of the Sun is about a quarter of your metabolic density and close to that of a lizard. To get around this different fuels are needed along with much higher temperatures. Still, if you can only figure it out, it sounds like the perfect goal - fuel from water and no radioactive waste.
The first serious attempt at magnetic confinement look place about 60 years ago .. it, along with every other effect until this last week failed. Those that achieved fusion required more input power than the power they produced. The figure of merit is Q: the ratio of the power of the fusion reaction divided by the power required to ignite and sustain it.
The laser confinement experiment announced focused a short pulse of light - about a billionth of a second - from 192 lasers onto a small gold container that vaporized to generate x-rays that collapsed a diamond coated fuel pellet of deuterium and tritium. The power of the laser light was 2.05 MJ (megajoules — a gallon of gasoline is 121 MJ, a hot dog in a bun is about 1.5 MJ) and the fusion explosion yielded 3.15 MJ. A Q of about 1.5. What isn’t mentioned is the efficiency of the lasers or the facility isn’t included - or the efficiency of extraction power from the miniblast. The lasers are less than one percent efficient so you can see there’s a long way to go.
This facility has been running for about a dozen years. It has been solving enormous engineering and applied science problems along the way as well as contributing to the pure science of understanding plasmas at this scale and temperature. Even the fuel pellets are very difficult to make and test. They have to be extraordinary symmetrical and most are rejected in testing - usable pellets are very expensive. What has been achieved is not a prototype, but rather a triumph of instrumentation technology along with the control of some difficult to manage parameters.
Moving this line of fusion forward seems like a long shot. A factor of five improvement may be possible with a redesign, but they need more than a thousand. Not impossible, but there’s a long path ahead.
There are other design types that confine microwave heated plasmas. Getting it right and working will take many years - probably decades and then there’s the issue of what does a facility cost compared to other types of power stations.
I hope work goes forward, but not at the cost of workable technologies that address global warming *now*. There’s so much that can be done, but very little political will.
building blocks
Watching Apple's Mac Studio announcement yesterday took my mind to something Carl Sagan said in the Cosmos series.
The Mac Studio's underlying technology goes far beyond the many tens of thousands of person-hours Apple has invested. The semiconductor industry that stands on the shoulders of Bell Laboratories back to the fundamental work of James Clerk Maxwell and before. Apple and others are able to come up with advances that strike us as dramatic as they make an impact on our lives. The impact of some innovations like the electric light, the telephone, the automobile, powered flight, radio, the atomic bomb and the Internet have changed how we see ourselves. But take a look and they're all built on long chains of invention and innovation that are often forgotten.
This comes to mind with the horrors going on in Ukraine. Russia has always had brilliant minds. They've made stunning advances in physics and math, but they haven't been as successful as the West in building on that. A good deal of their technology is derivative. In the past 25 years this may be by design. Most of the export value comes from extraction - oil and other natural resources. These industries seem to fall under the direct control of Putin's friends. More technical industries are still under oligarchs, but these aren't super high profit. As long as the core players can control them, the real focus of the economy is what can be run by shear force and power rather than technology and sound business practices. (note - this is speculation as I'm certainly not a Russian expert.. so take it with a grain of salt).
High tech industry is required for the military and some consumer use. Although that is supposed to be home-brew there is a lot of importing and rebranding. I've seen that in electronics used in physics experiments and am told is standard operating procedure.
So imagine you can't important and rebrand the CNC tools necessary to make jet engines. Can you make the tools yourself. What if you can't even make precision bearings? What if China doesn't allow electronics into the country (they probably will, but now they can be the Mafia dons)? Sanctions can make a medium and longterm impact.
You don't need to make your Apple pies from scratch - we have our universe - but few companies or countries have the capability to build objects of the modern world without technologies that exist outside. All of these long threads few of us think about until they aren't available. Think about all of those high value products waiting for fifty cent ICs that were designed twenty years ago...
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PS - I'd love a Mac Studio, but it's way beyond my budget.
Posted at 04:57 PM in general comments, history of science, history of technology, manfacturing, society and technology | Permalink | Comments (0)
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