It seems that for the last couple decades fusion is always 30 years away and by this point we’ve well passed the initial 30 and seemingly little progress has been made.
Is it just that it’s so difficult to make efficient?
Has the technology improved substantially and we just don’t hear about it often?
In: Physics
Because fusion means merging one atom nucleus with another one. However that is not easy, since equal charges repel each other, since ALL the atoms nucleus possess equal charge(positive – protons), they ALL repel each other.
Given that, fusion can only happens under EXTREME conditions, either when atoms are running really really fast(which means they’re really really hot), then they hit each other with tremendous amount of energy, releasing an EVEN BIGGER amount of energy in the process. Or when a gravity at the center of a star is so great, it forces one atom nucleus against the other.
How hot do we need to get? A few millions of degrees celsius within a star, hundreds of millions of degrees celcius within a reactor. Fact is, the Sun, or any other star cheats, due to the IMMENSE gravity they have, the atoms inside their nucleus don’t have a choice besides fuse with each other, releasing an enormous ammount of power during billions of years.
But that’s the issue, we can’t and never will be able to simulate a star’s gravity on Earth, hence we need to follow the first path, which is colliding atoms against each other at tremendous speeds and energy. To accomplish this we need to heat the gas into a really really high energy level, 150,000,000 ºC at least.
That’s the problem, we don’t and we can’t never have a material with a melting point that high, hence we need to isolate that soup made out of REALLY REALLY HOT atoms as far from the walls of the reactor as possible. Which fortunately is easy, atoms that hot can get isolated by exposing them to a really strong magnetic field, since with that temperature they attain a matter state called plasma, which basically means a soup of really really hot and ionized gas.
Then comes the second part, which consists to force this large cloud made out of plasma into a really really small area, in order to maximize amount of fusion taking place. That feat is REALLY REALLY HARD, since those atoms REALLY WANT to get as farther away from each other, because the repelling force I mentioned before. At the moment we didn’t manage to get more fusion energy OUT than we PUT INTO the reactor to attain these EXTREME conditions, but it’s theoretically possible and should be doable at least.
We are still decades away from a fusion reactor, and realisticaly we may never be able to pull this feat off, however if we manage to sustain a fusion reactor that outputs more energy than it consumes, we are going to skyrocket as civilization, since the fuel required to make it work is abundant and easy to get(both, lithium and deuterium are found in abundant levels within sea water, at much higher amounts compared to the fissionable atoms), one cup of deuterium and lithium(which is going to be breed into tritium) should be enough to release an energy compared to a barrel of oil burning away.
So it still worths the endeavour, stay tuned to the news, the ammount of effort and funding it’s taking is enourmous with many new players entering the race(startups aiming to generate fusion energy), and we may be surprised in the next years.
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