Thursday Throughput: Laser Implosion Edition

U.S. Department of Energy from United States, Public domain, via Wikimedia Commons

[ThTh1] We’ve had hints of this before, but we finally have a sustained reaction:

Scientists studying fusion energy at Lawrence Livermore National Laboratory in California announced on Tuesday that they had crossed a long-awaited milestone in reproducing the power of the sun in a laboratory.

The result announced on Tuesday is the first fusion reaction in a laboratory setting that actually produced more energy than it took to start the reaction.

Fusion, as we’ve spoken of before, is when atoms are combined to create new elements. If the elements are light — hydrogen being the lightest — the fused atom will convert some of its mass into energy. Even though the amount of mass destroyed is small, the amount of energy produced is large because it comes to us via one of the most famous equations in history.

The energy is equal to the mass times the speed of light squared. And light is so fast it took us thousands of years to realize it moved at all.

The problem with creating fusion is that atom nuclei are positively charged and therefore repel other nuclei. The amount of energy needed to overcome that repulsion so enormous there are only a few ways to do it:

• Be in the center of the Sun, where the pressure and temperature are so extreme that atoms smash together. This is very useful to us creatures who need sunlight to survive but it’s rather impractical to put the Sun in Kansas to provide energy.
• Set off a nuclear fission reaction. In thermonuclear weapons, a fission nuclear bomb superheats a secondary hydrogen bomb, igniting fusion and creating an even bigger explosion. This is useful if you want to destroy a city but not so much if you want energy for more than a few seconds.
• Use a magnetic field to squeeze a ring of plasma together until the atoms unite. This is the basis of the tokamak reactor design, which has previously approached breakeven, the point where the energy being liberated from the hydrogen atoms equals the amount being used to crush them together.

The new experiment uses a laser implosion technique. A small pellet of carbon-shrouded hydrogen is injected into the central chamber. It is then blasted by 192 lasers. This vaporizes the surface but also creates a reverse shock wave that compresses the hydrogen. On December 5, the Lawrence Livermore Laboratory blasted a hydrogen pellet with 2 Megajoules of laser energy and about 3 Megajoules of heat energy were released. They not only broke even, they profited a handsome sum. Not only that, but the reaction kept going for a while until about 4% of the hydrogen was consumed. They didn’t just break even; they created ignition, when a fusion reaction becomes self-sustaining. The reaction was short — only a few billionths of a second. But in that fraction of a second, it was producing more energy than the entire US power grid.

If nuclear fusion can be made practical, it will crush our energy problems. The supply of hydrogen — even the rare isotopes of deuterium and tritium that are used in fusion reactors — is abundant enough to meet our energy needs indefinitely. Nuclear fusion produces no fuel waste and there is no chance of meltdown.

So is nuclear fusion power just around the corner? Look, I’ve been writing on the blog for a while and those of you who know my style know the bucket of cold water is about to be thrown.
There are still huge hurdles to overcome. For one thing, we’re just comparing input energy to output energy. But the energy needed to power the laser was about a hundred times the energy went into the reaction. So this reaction needs to be sustained for a long time to pay back that input. This was also one single shot of the lasers at one single pellet that took months to set up; a practical reactor would need to be doing this many times a second and at a tiny fraction of the cost.

However, that shouldn’t discourage us. Almost every breakthrough starts like this. Air travel was only for elites and the military and now you can fly to Cleveland for less than the cab fare to the airport. The first computers took up entire buildings, cost a king’s ransom and required intricate maintenance. There are now baby toys that have more computing power. Once scientists know that a thing can be done, it tends to supercharge the push to make it routine and profitable.

Moreover, many of the remaining breakthroughs will need to be made by industry. One of the things I emphasize in science policy is that national facilities — like Livermore — should do basic research and then hand off their discoveries to industry to do the applied research to make their discoveries practical. The data from this experiment will energize¹ the budding fusion industry. There are a couple of dozen companies out there working on this.²

There has been a running joke that fusion power is always twenty years away. I would say that we are now to the point where fusion power is ten years away. This is one step on a very long ladder. But it’s a big one. And if we ever get to the top, the view will be tremendous.

[ThTh2] Archeologists recently uncovered an 11,000 year old piece of narrative art. And it seems like some things never change.

[ThTh3] There are a lot of videos floating around of people collapsing upon exposure to Fentanyl. Dont fall for the hype. This is stuff is dangerous but it’s not magical.

[ThTh4] What a single fireball can tell us about the early solar system.

[ThTh5] Learn about nanoseconds from the amazing Admiral Grace Hopper.

#OTD in 1906, Grace Hopper was born. Rear Admiral Hopper was an barrier-busting pioneer of computer programming and a major advocate of innovative thinking. During her 1986 appearance on Late Night with David Letterman, she gave her famous demonstration of a nanosecond. pic.twitter.com/WIp26GywRr

— U.S. Naval Institute (@NavalInstitute) December 9, 2022

[ThTh5] And this week in stunning JWST images: the weather on Titan.

A Titan-ic success!

Here is Webb’s first look at Saturn’s largest moon, Titan. Because Titan has a dense atmosphere, its surface is hidden in visible light. Enter Webb’s infrared eye, which captured clouds as well as bright & dark patches on its surface: https://t.co/zQsSN9Py4H pic.twitter.com/6NuQMfXAFN

— NASA Webb Telescope (@NASAWebb) December 1, 2022

[ThTh6] And also discovering the earliest galaxies.

[ThTh7] Oh, and chemical reactions in other star systems.

[ThTh8] Meanwhile, back in our boring old Solar System, life on Venus just got a lot less likely.

[ThTh9] The amount of misinformation flying around about COVID seems to have exploded lately. Here is a guide to the facts. Vaccines work. COVID is still dangerous. Get your booster.

[ThTh10] A new vaccine may give hope to one of the most brutal cancers out there.

[ThTh11] Your truly is quoted in a nice article by Lenore Skenazy about whether kids aren’t looking at the sky enough. The good news about looking at the sky is you don’t need a lab coat or even a telescope to enjoy it. All you need is a dark sky and some time.

1. Pun definitely intended.
2. For the record, I still think the tokomak design is the more likely to produce practical reactors. But I’m delighted that we now have two potentially viable approaches.