Well, hello.

I'm making this page because, for some reason, I feel like talking about Magnetohydrodynamic Generators (MHD generators for short), but I don't have any kind of project log to talk about it.

I would want to make a new project on this subject, but let's be honest, I'm broke and not a professional in any useful area, so it is most likely I would left the project to rot and unnecessarily fill up Hackaday's memory.

But being honest², I do feel tempted in making such project because I have a faint hope that someone more qualified than me would see and try it.

In any case:

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Magnetohydrodynamic generators:

These kinds of generators are just like alternators, but with no moving part and using plasma instead.

What do I mean: alternators have electromagnets on both the rotor and the stator, once you rotate it, the disturbance in the electromagnetic field will generate energy.
A MHD generator maintains electromagnetic fields that maintain a conductive medium (normally plasma), once a disturbance in this equilibrium appears, it is turned into energy.

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The problems:

The first issue that one notices when researching about the subject is the lack of information and the lack of large scale applications of such generators (with the exception of being used on rocket engines).

I can barely find any information on the subject and it always substantially changes depending on the article/news paper you are reading.

Some websites say that the MHD generators aren't viable because they achieve plasma by superheating gases until they turn into plasma, others say it is because they need a "seeding material", which is normally a radioactive isotope of some random material that will "seed" ions on the gases, turning them into plasma.
And finally, others say it is because it only produces enough energy if they use blasts that travel through tunnels, which need to be as strong as conventional explosions. Which is dangerous and damages materials.

It is probably all the three and more, but the issue repeats itself: there isn't enough information on the subject.

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The ideas:

Not knowing enough about the subject and not having enough money even to test the most basic of MHD's didn't stop me from imagining how I would do it (even though it is the most incorrect and unpractical idea).

The first thing it comes to mind are toroidal plasma fusion reactors, or Tokamaks:

Of course I'm not saying "Imma turn MHD's into fusion reactors 'cause it is easy", I'm saying that tokamaks are possibly a good blueprint for different MHD generators.

But this put into question: "if they were so good as you say, then why there aren't any MHD with such shape?"

And to be honest, I don't know and I'm probably wrong.

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In either way, I do think that fusion reactors will eventually become some type of magnetohydrodynamic generators, because it is way simpler to extract energy like this.

Today's proposals focuses on using the heat generated that hits the walls to turn water into steam.

Which, needless to say, seems quite... Unpractical.

I'm not saying that I know better than the physicists that are creating these marvel of technologies, but I always question myself on how they are going to do it when the fusion they create literally and absolutely destroys the reactor itself from inside.

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If I had the capacity/knowledge/competency/budget to do so, I would try to research how to make walls of plasma.Imagine it like this: 

Every layer in this plasma donut is a different gas being ionized, and each gas ionized helps with the fusion and protects against damage on the reactor.

The center is obviously the hydrogen being reacted, while heavier gases like nitrogen or argon gas are used to shield the reactor's walls.

You could maybe even use lithium gas in order to further feed tritium into the fusion reaction, since lithium produces tritium hydrogen when under radiation.

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One possible way of maintaining such layers would be using electromagnets with halbach array.

The K=4 is used on particle accelerators, and MHD could use the same one to make these plasma walls.

Of course, the halbach array is used for permanent magnets, but you can also use it for electromagnets.

However, I don't know how well these would work.

If it was that simple, people would've be using them for their fusion reactor for ages, but the electromagnet system in these reactors are way more complicated than that.

This video explains quite a lot how the electromagnets are organized, the blanket problem and so on.

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Combustion Magnetohydrodynamic Generators:

And thus, we come back to normal MHD generators.

The idea I had with the subject was precisely to use the same ttechnique and principles, but with fossil fuels. At least you wouldn't need to use helium-cooled superconducting electromagnets (I think).

Hot air and fuel would be injected into the chamber while being turned into plasma by microwave heaters (just like the microwave furnaces), the fuel-plasma would eventually react and be replaced by new fuel-plasma and be naturally ejected from the reaction, making layers of protection until they are finally expelled.

One way of making this would be using turbochargers, which use the exhaust to spin a small turbine that spins a compressor.

... But this sounds a bit like a turbine engine, but with a MHD generator attached to its combustion chamber.

Which wouldn't be a bad addition (I think), since you would increase the overall efficiency of the system.

Another idea would be to use Pulse-jets.

These Jet engines are incredibly powerful, simple, light and inneficient (around 5%).

However, this could also be their strength in a MHD. After all, the disturbance in the plasma is what generates electricity on such generators.

Most of the energy wasted in a pulse jet is due to heat and vibration, and you could tune said vibration in order to make it more predictable for electromagnetic control.

You could make an "injector" of pulsejet in a conventional MHD generator or even a molten metal MHD generator (yes, certain liquid metals are conductive).

I couldn't find the video that I wanted, but basically some guys in a garage attached magnets to a drill and started rotating them next to a molten aluminium crucible to mix it with a non-soluable powder for a aluminium composite.

One could also use liquid metals or conductive liquids in generall (I think), ike mercury, molten tin or water.

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I'm probably wrong.

But anyway, this is it.

Most definitely I'm soundly wrong and there are good reasons on why Magnetohydrodynamic generators aren't a widespread thing. Specially toroidal ones.

Not to mention the Plasma wall thingie.

Also, Fusion Reactors (and I would suppose, MHD's too) need super precise and complex algorithms in order to properly predict the plasma behavior for making a stable plasma reaction.

Plasma interferes, reflects and conducts electromagnetic waves at same time, so it is super hard for making a stable fusion reaction.

I heard once that chaos theory is that the more you try to interfere in a chaotic system, the more you are able to control it. But I mean, duh?

Also, I was wondering if it would work to "let" the plasma become unstable in a controlled way, like turning on the electromagnetic field and turning off the moment it starts to distabilize just to turn it on again.

... But I doubt it is that simple, there are way more competent people working on this and I just wanted to talk about MHD's with someone.