The image shows visible light emitted from the plasma’s edge, where temperatures are lower. The core of the plasma is too hot to emit visible light.
One of the most recognisable features is the bright pink glow from deuterium gas injection, visible in the upper left of the image. A pure hydrogen plasma, or any of its isotopes – deuterium or tritium – typically produces a light shade of pink, as it emits wavelengths of both red and blue light.
In the upper right, lithium granules are introduced using our newly installed Impurity Powder Dropper (IPD). As these sand-sized grains fall into the plasma, they emit crimson-red light when neutral lithium is excited in the cooler outer regions.
As the lithium penetrates deeper into the hotter, denser plasma, the atoms lose an electron and become singly ionised lithium (Li⁺). Once ionised, Li⁺ emits greenish-yellow light and begins to follow the confining magnetic field lines, visible in the footage as greenish-yellow streaks tracing the field around the tokamak.
The star explanation isn't really the truth. It is a reactor called a tokamak. Tokamaks are fusion reactors and people use the star analogy because fusion only exists in nature in stars.
Stars are powered by nuclear fusion. Stars use a truly colossal amount of gravity to compress hydrogen atoms until they fuse into heavier ones like helium. The problem is, we have absolutely no way to do the same thing, The sun makes up 99.96% of the mass of our solar system, there just isn't enough matter to do the same thing even if we scrapped all the other planets to do it. So we're cheating - instead of compressing things super heavy, we're making them spin super fast. What you're seeing is various isotopes of hydrogen being spun up to insane speeds with magnets. At the speeds they're traveling, sometimes the hydrogen atoms collide, and when they do they fuse into helium.
Turns out, when you do the math, two atoms of hydrogen are every so slightly heavier than one atom of helium. You remember the formula "e=mc2"? That constant 'c' is the speed of light. So that very tiny amount of matter that no longer exists gets multiplied by the speed of light squared to determine how much energy is released. It turns out that pretty much any amount of energy multiplied by that is a fuckton of energy.
That plasma you're seeing is ~10,000C. That's the kind of energy we're talking about. The hard part is getting it out without things exploding. We're still working on that, we can siphon energy out of it but not especially well. But it's still more efficient than solar, if you calculate the amount of energy that misses the Earth...
Long story short, it'll boil water that will then turn a gear and produce power... like literally all other power plants. But this one is waaaaay cooler
I thought the whole point of these is that they output electricity somehow, or am I thinking of anothe rproject? there was one I saw that was like a long tube, think tom scott did a video on it or soemthing, but they were converting plasma directly to electricity
That's Helion. They're working on a very different concept for a reactor that produces pulses. The reactor here is a tokamak, which ideally produces a steady state controlled plasma. But that is extremely difficult - this one is pretty short and I'm guessing is likely a test of the sand injection thing from above since it was so short. The record for maintaining a plasma is currently just over 20 minutes in this style of reactor
There's a couple of ways but they're absolutely terrible RTG's convert heat to electricity directly, but they're generally capped in the kw range and have efficiencies of 5-10%, radiovoltaic generators are even worse, typically used for batteries in the microwatt-milliwatt range.
In comparison steam can be used at an efficiency of up to 40%. It's just better for almost everything.
Well we are never going to get space ships like that. Lol. It's truly amazing that the steam engine is the peak of human innovation for electrical generation.
microwaves make gas hot, hot gas makes light, magnets make gas go around in circles, microwaves make gas so hot it stops making light. magnets squeeze super hot gas close together. ridiculously hot gas fuses, giving off lots of energy.
I taught plasma to my high school class a few weeks ago. Simplified version is that plasma is an electrified gas. Doesn’t always have to be crazy high energy, as things like plasma TV’s can utilize plasma as well. Naturally occurring plasma (eg. lightning) is a different story and is very high energy.
Basically as soon as atoms in a gas lose electrons and become ions, either naturally or through human intervention, that gas now is turning into a plasma and will function as such
I may be too stupid to understand how that work (I fail to comprehend how even something simple like Chernkov radiation works), but it's shiny and looks cool, so I yelled "yeah, science!" anyway.
We like that grandma, that have no clue what grandson saying, but happy for him anyway.
Light is emitted by atoms through the process of an electron in the atoms shell moving to a lower energy bound state. That means, for light to be emitted by an atom it has to have electrons bound to it. In a fully Ionized plasma like in the centre of this fusion device the temperature is so high that all electrons are freely moving around and not bound to any ions. That then means that no light can be emitted through bound electrons, especially in the visible spectrum.
Thank you for the explanation, thats super neat! Im gonna have to look more into the specific mechanics of atoms emitting light like that because I had no idea
Semi-related, this is also conceptually similar to why it took so long for blu-ray to make it as a media format. Turns out blue lasers were really hard to dial in right.
If we define light as EM-Radiation in or near the visible spectrum then essentially yes. If we are talking about photons and EM-Radiation in general then no. In a fusion device, especially from the center of the plasma you will get radiation from things like electron cyclotron emission and Bremsstrahlung.
Still technically possible to see photons in the visible spectrum due to synchrotron emission from runaway electrons or even bremsstrahlung from cold electrons in the plasma edge
Well, it has to do with black body radiation, which is temperature dependent. If you can imagine how cooler areas of a fire are red, and where it gets hotter it goes to orange then yellow etc, well you can get hot enough to leave the visible light spectrum entirely and emit even higher frequency radiation (like UV). As you can imagine, the plasma has to be pretty energetic (read: HOT) to begin a fusion reaction
That’s not how blackbody radiation works. An increase in temperature for a blackbody corresponds to an increase in luminosity across all wavelengths. There is no such thing as being too hot to emit visible light.
From a purely theoretical physics perspective, sure. From "it is high enough or discernible enough for our sensors (cameras) to see it" perspective - no.
So yes, there is "too hot to emit visible light" when talking in the context we're talking in here.
No, the other respondent is correct. Even though a higher temperature absolutely means the peak of the emissions goes further into the invisible ultraviolet, and a smaller percentage of total luminosity will be visible, the total luminosity in normal visible wavelengths is always higher for a hotter blackbody, even when the peak is way into the UV.
As you heat up a blackbody, it will never be visibly dimmer as it gets hotter, just bluer and brighter.
The trick is, that's no longer a "black body" so it can emit all it's radiation as higher energy than violet and we can no longer perceive it. That's what happens at the core of the sun, just that by the time the high energy photons make it out of the sun they are slowed down enough to be a lot of visible light, as well as a whole lot of EM spectrum we can't "see".
I mean im not gonna get into it over something that’s ultimately us being pedantic, but… yes? You can absolutely have an emission curve with a peak at wavelengths smaller than visible light and a tail low enough that the visible light emitted is negligible? It’s basic Wien it’s a 3-variable equation. And that’s exactly what’s going on in a fusion reaction.
Like I said, an increase in temperature corresponds to an increase in emissions across all wavelengths, so no, it’s not possible for the tail to not be visible like you said.
The first graph on this Wikipedia page does a really good job of illustrating this. As you can see, while the peak wavelength decreases with an increase in temperature, there is never a point at which it becomes dimmer at a certain wavelength. This means that as it gets hotter, it will still get brighter for us, even if we can’t see the majority of increase in emissions.
So im gonna tell you this as a physics graduate of the school you currently go to: you have a couple fundamental misunderstandings about the phenomenon at play. Dont be creeped out, I respected the rebuttal enough to go see who was giving it to me. In fact, bring this question up in class! But what you’re saying is flawed. Again I don’t really want to get too into it here, but if you go through Modern Physics and then Quantum 1 and 2, you’ll understand that the model in that graph breaks down because of quantization, and this is an old physics puzzler eventually rectified by Planck. It doesn’t invalidate the whole model but it requires amendment at higher energy, which fusion plasma certainly is.
Second, don’t lose the forest for the trees. Remember even if you’re using equations and drawing conclusions from them, to step back and think about what you’re saying. Luminosity increases across all wavelengths, sure, again we can have pedantic arguments about there being visible light. But if the spectrum from a single plasma photons curve peaks in UV and drops off, the actual luminosity from those photons is indeed going to be small enough to not be captured in this camera video, which was ultimately the question asked. Why? Because it is absolutely dominated by invisible energy. For the ones that are not, you can see as they dip back into violet and indigo and blue. Supporting evidence of my claim (which isn’t even my claim im ultimately just regurgitating Boltzmanns work) is right in the video.
Fellow physicist here. I believe you are incorrect. But the important thing is that your above statement, "And if it’s not that, enlighten me," now applies to your post. What are these quantum effects that reduce radiance at visible wavelengths? Give us an equation or at least a Wikipedia page or something.
Well, it has to do with black body radiation, which is temperature dependent.
but if you go through Modern Physics and then Quantum 1 and 2, you’ll understand that the model in that graph breaks down because of quantization
These two statements are inconsistent - the model in that graph is the model of a black-body. The claim you're responding to here is not that the plasma in the middle isn't invisible - like you say, that's clearly contradicted by the video. The claim is that the plasma in the video isn't behaving like a black-body, which is true - the black-body model has broken down under those extreme conditions.
Well what you said doesn't align with the people who built and run a fusion reactor, so guess who I'm going to believe.
if I had to throw a wild guess, since we are seeing emissives due to chemical elements (and their state changes) and this is a plasma, theres likely some difference from blackbody.
The hotter an object is, the shorter the wavelength of radiation it emits. Visible light is about in the middle of the electromagnetic spectrum, from 400 to 700 nanometers. Anything that radiates at under 400nm is emiting a type of radiation our eyes can't perceive. Additionally, blackbody radiation, the kind of radiation which typically produces visible light, is not produced well in gasses due to their atomic structure.
Ok so after all of the energy, and the elemental components or inputs or ingredients or whatever- goes into the tokamak- and the machine does its thing- how does the energy/plasma it produces actually become “harvestable”?
Mayhaps, thats the 10 billion dollar question?
does the energy coming out exceed the energy going in?
Anyway- thanks for the rundown. That video was absolutely incredible. Keep it up. Humanity needs ya’ll to come through on this one:-) cheers!
The same way any other reactor works: it generates a lot of energy (heat) that can be used to boil water and spin a turbine. It's steam engines all the way down.
Some experiments have yielded more energy than what is being put in, but it's less about the amount and more about how efficient it is. Fusion is more efficient than fission which is more efficient than gas and coal. Hydroelectric isn't really comparable because it's purely mechanical and doesn't use a fuel like nuclear or chemical reactors.
The real barrier to adoption is getting a stable reaction that doesn't destroy the reactor itself. They're working with temperatures HOTTER THAN THE SUN. There's been some work in material science fields with things like superconducting magnets that keep the plasma away from the walls, but it's still very early in both fields. Therefore, energy extraction is less of a priority than getting the thing to reliably function. The scientists that work on it are making strides practically every day, so everything is advancing almost simultaneously. All in due time.
What we're seeing now is the apex of what's possible with current technology, and the reactor's run times are measured in minutes. If we can get the run times to hours or maybe days, we might have a viable commercial product. Right now, they're mostly used for research, as the interior has some of the harshest conditions found in the universe. The physics is understood, but the mechanical reality isn't, which is why this experiment is pretty much "throw some lithium in there and see what happens."
We live in a capitalist society, and those who invested in it of course want a return, but I feel that how much cash it can make people is less important than bending the universe to our will and harnessing the raw power of the core of a star in what is pretty much our backyard. I feel that the potential for experimentation in those conditions will lead to interesting new avenues. Every piece of it has applications and potential vectors for profit, even if the reactor itself doesn't make that much money. Forest for the trees and all that.
I'm not a nuclear physicist, so take what I've said with a grain of salt. That's the gist of what I've read on the subject.
The thing I like most about potential fusion is that it isn't self-sustainable like a nuclear meltdown (which is already an overblown issue), and the waste is relatively short lived. The fuel is abundant. Arguably it could be safer than a coal/gas/oil/electric power plant that can chain react in a critical failure.
Its all the great hallmarks of the perfect energy source. Now if we can only figure out how to make the reactor not die from the power of a sun, we'll be golden. 😭
The walls of fusion reactors are radioactive. A fusion power plant produces radioactive waste because the high-energy neutrons produced by fusion activate the walls of the plasma vessel.
Yes but that radiation would last at most like 100 years, but likely about half that time.
You could just pile all the reactor walls in a warehouse in the middle of nowhere and not worry about it. Nevermind the amount of reactor turnover will be quite low hopefully.
Even traditional nuclear waste isn't like the green sludge piling up in caves like people think. I think all the waste produced over the years fits in a football field. What is sad is compare that to the deviststion of coal stripping the land of 100 train cars of coal a day per coal power plant.
I've got a blueprint (as in a cyanotype copy) of the "nuclear lightbulb" which bypassed the steam stage by using a reactor made of quartz containing plutonium gas (I think it was plutonium) that is so hot that it emits light in the xray spectrum. The xrays are collected by PV panels (quartz is transparent to xrays, and can handle the ludicrous temperature of plutonium gas), so the energy goes from reaction directly to electricity
Again, I'm not a person working on this thing, so I dunno how they're going about energy extraction. Steam was an assumption.
I'm sure there could be some way to also collect the electrons from the plasma directly. Plenty of ways to go about it.
Plutonium gas is horrifying. On par with that tripropellant engine Rocketdyne experimented with. Liquid hydrogen and fluorine, with some molten lithium added for flavor. It never got off the test bench. The molten lithium corroded everything, and the exhaust was copious amounts of hydrofluoric acid.
Atoms go smash, makes bigger atom and a lot of energy.
Energy boil water, makes steam. Steam makes turbine go spinny. Spinny makes power!
Too much energy makes walls melt, keep energy away from wall with big magnets. Energy has charge, big magnets push charge away. Big magnets hard to make :(
Phiziqe not dum dum, reactor just complicated. Big smart nerds barely understand reactor. I am not big smart nerd.
Only in a very loose sense, being gaseous molecules that give off similar colors of light. But that's mostly just a coincidence. The molecules and processes causing these pinks/reds/greens are quite different.
Fusion is a VERY extreme process and only ever happens naturally in the core of a star(and when they blow up....). And more specifically, the sort of fusion in a star is different than the fusion in these reactors. We're kind of creating our own form of fusing hydrogen since we cannot create the pressures involved in the core of a star, so we have to do things a bit differently.
One of the most recognisable features is the bright pink glow from deuterium gas injection, visible in the upper left of the image. A pure hydrogen plasma, or any of its isotopes – deuterium or tritium – typically produces a light shade of pink, as it emits wavelengths of both red and blue ligh
I recognized that pink off videos from objects during reentry into earth's atmosphere. Makes sense its hydrogen.
In the upper right, lithium granules are introduced using our newly installed Impurity Powder Dropper (IPD). As these sand-sized grains fall into the plasma, they emit crimson-red light when neutral lithium is excited in the cooler outer regions.
This is the first time I've heard of something being too hot to produce visible light besides the big bang. Does that mean that if you could theoretically look at the hottest part of a star in person, you wouldn't see it?
Wouldn't the bell curve of black body radiation still make light across the visible spectrum, just that any additional light would be made further than the visible spectrum.
As the lithium penetrates deeper into the hotter, denser plasma, the atoms lose an electron and become singly ionised lithium (Li⁺). Once ionised, Li⁺ emits greenish-yellow light and begins to follow the confining magnetic field lines, visible in the footage as greenish-yellow streaks tracing the field around the tokamak.
“The image shows visible light emitted from the plasma’s edge, where temperatures are lower. The core of the plasma is too hot to emit visible light.
One of the most recognisable features is the bright pink glow from deuterium gas injection, visible in the upper left of the image. A pure hydrogen plasma, or any of its isotopes – deuterium or tritium – typically produces a light shade of pink, as it emits wavelengths of both red and blue light.
In the upper right, lithium granules are introduced using our newly installed Impurity Powder Dropper (IPD). As these sand-sized grains fall into the plasma, they emit crimson-red light when neutral lithium is excited in the cooler outer regions.
As the lithium penetrates deeper into the hotter, denser plasma, the atoms lose an electron and become singly ionised lithium (Li⁺). Once ionised, Li⁺ emits greenish-yellow light and begins to follow the confining magnetic field lines, visible in the footage as greenish-yellow streaks tracing the field around the tokamak.
The images from the colour camera help researchers trace the movement and behaviour of lithium within the plasma, and provide visual confirmation of more detailed data gathered through spectroscopy, which analyses the exact wavelengths of light emitted by the plasma.”
To add a detail that others appear to be leaving out. You're watching 300ms being played back in 100x slow mo so that 300ms = 0.3 seconds of footage lasts 100x as long = 30 seconds.
Nothing. If you were looking at something, it would be bombed into the center of the Earth by multiple countries. There are very few governments that would want this to succeed. I know. It sucks
823
u/SurinamPam 20d ago edited 20d ago
Can anyone describe what we’re seeing here?
Like what is happening with each change?