I don't think they generated any fusion reactions, I believe they used just natural Hydrogen rather than Deuterium and Tritium (which would normally be used for fusion fuel). Also, magnetic confinement fusion reactors don't explode, they are like pencils balanced on their points, when something goes wrong or they "lose containment" the pencil falls over, the fusion conditions dissipate and reactions stop. This test was just one step along the way of verifying the plasma dynamics and heating capabilities of the system, it'll be a while before they do fusion reactions, and it will never produce energy from fusion. But be aware that making fusion reactions happen is easy, it's the matter of creating a self-sustaining fusion reaction that's hard.
In magnetic confinement fusion there is a big problem of confinement stability. You are trying to confine a plasma, which is electrically charged and thus an electrical conductor. Electric current generates a magnetic field. This is actually made use of in tokamak designs, which are the most straightforward magnetic confinement systems. However, tokamaks suffer from a fundamental flaw, that plasma current produces a feedback instability loop making it very challenging to attain plasma confinement longer than a few seconds or minutes. That's problematic because the shorter lived the fusion plasma is the more the initial (externally produced) heat as a proportion of the total cumulative heat of the plasma over its lifetime adds up. Short lived plasmas don't spend very long producing fusion heat to "pay back" the energy used to heat up the plasma to fusion conditions to start with.
A stellarator is basically a way to twist the magnetic fields around the fusion plasma tube in such a way so that the trajectories of ions in the plasma will stay inside the confinement volume, without requiring any current in the plasma. This makes the system potentially much more stable but at the cost of a very much more complex arrangement of magnets. The longer the plasma can be confined the longer fusion reactions can be sustained, making it easier to generate more power than was put in to raise the plasma to fusion suitable conditions (high density, high temperature).
> This is actually made use of in tokamak designs, which are the most straightforward magnetic confinement systems.
Wrong! The most straightforward magnetic confinement systems are :
- Simple toroid design -> Have some flaws that make useless and Stellerator is a evolution of the idea, fixing it with twisted magnetic fields.
- Magnetic mirrors -> Two simple coils separated, so the combination of the shape and the more dense magnetic field on the center of the coils, works like a mirror for charged particles.
Also, at nearly the same time (around 1955) that the Russinas was begin to experiment with the Tokamak design, the British was experimenting wit the "ZETA", where the contaiment magnetic field comes ONLY from a current on the plasma.
Huh, that last part sounds kinda interesting. Pardon my scientific ignorance, but is that 'self-containing plasma' phenomena the reason why our Sun hasn't exploded yet?
It's a few grams of plasma, and it's inside of a huge metal contraption. If you "lose containment" the plasma just expands, contacts the walls of the reactor, and cools off. It's kinda bad for the reactor because high temperature plasmas tend to chew through materials, but fusion reactions stop, it's a non-event outside the reactor. In fact, losing containment is typical, modern fusion reactors can't contain plasmas very long, only a few seconds. The normal operation of a reactor is magnetic containment for a few seconds, then loss of containment, followed by later "shots" of fusion plasma being contained and heated for another few seconds, and so on.
In magnetic confinement fusion there is a big problem of confinement stability. You are trying to confine a plasma, which is electrically charged and thus an electrical conductor. Electric current generates a magnetic field. This is actually made use of in tokamak designs, which are the most straightforward magnetic confinement systems. However, tokamaks suffer from a fundamental flaw, that plasma current produces a feedback instability loop making it very challenging to attain plasma confinement longer than a few seconds or minutes. That's problematic because the shorter lived the fusion plasma is the more the initial (externally produced) heat as a proportion of the total cumulative heat of the plasma over its lifetime adds up. Short lived plasmas don't spend very long producing fusion heat to "pay back" the energy used to heat up the plasma to fusion conditions to start with.
A stellarator is basically a way to twist the magnetic fields around the fusion plasma tube in such a way so that the trajectories of ions in the plasma will stay inside the confinement volume, without requiring any current in the plasma. This makes the system potentially much more stable but at the cost of a very much more complex arrangement of magnets. The longer the plasma can be confined the longer fusion reactions can be sustained, making it easier to generate more power than was put in to raise the plasma to fusion suitable conditions (high density, high temperature).